Method for decomposing compound

Abstract

[Problem] To provide a novel method for depolymerizing a super engineering plastic such as a polysulfone. [Solution] This method for depolymerizing a compound has a decomposition step for reacting a first compound represented by general formula (1) with a second compound represented by general formula (8) or a hydroxide thereof in the presence of a base so as to decompose the first compound (in the formulae, n1 is an integer of 2 or more; Z11 and Z12 are each independently a group other than a hydrogen atom; m11 and m12 are each independently an integer between 0 and 4; Ar1 is a group represented by general formula (91), (92) or (93); R8 is an alkyl group, an aryl group or an aralkyl group; X11, X12, X21, X31 and X32 are each independently a group other than a hydrogen atom; and l11, I12, I21, I31 and I32 are each independently an integer between 0 and 4).

Description

How to decompose compounds

[0001] The present invention relates to a method for depolymerizing (decomposing) a compound.

[0002] Polysulfone, a super engineering plastic, is a thermoplastic resin that not only boasts excellent heat resistance, a wide range of operating temperatures, hydrolysis resistance, chemical resistance, and electrical properties, but also possesses ideal properties as a processable material, such as mechanical strength, transparency, moldability, and weather resistance. These properties have led to a wide range of applications for polysulfone, including medical and food-grade materials such as medical biomembrane substitutes, artificial kidneys, medical instruments, food containers, and cookware parts, as well as electronic components such as connectors and printed circuit boards. Highly stable thermoplastic resins similar to polysulfone include polyether ether sulfone and polyphenyl sulfone, both of which possess excellent material properties similar to polysulfone. Furthermore, these resins are characterized by the fact that part of their main chains is composed of bisphenols or hydroquinones, which are also commonly used in other organic materials, making them highly valuable as molecular materials. As of 2019, the total production volume of polysulfone and polyphenylsulfone was 26,600 tons, and the production volume of polyethersulfone was 16,870 tons. At first glance, this may seem small, but considering that these are expensive resins, this is by no means a small production volume. These super engineering plastics, with their excellent properties as described above, are indispensable materials in industry now and in the future.

[0003] However, due to their high stability, these super engineering plastics are extremely difficult to dispose of and recycle. For example, because they contain many benzene ring skeletons in their molecular structure, they are difficult to decompose using microorganisms. Therefore, they place a heavy burden on the environment and pose serious problems in the future. In fact, the only chemical recycling technologies for super engineering plastics disclosed to date are those related to the decomposition of polysulfones into smaller molecules (see Patent Document 1) and the decomposition of polyphenylene sulfide and polyethersulfone into monomer and oligomer units (see Patent Document 2 and Non-Patent Documents 1-6). Of these, the chemical recycling technology for polyethersulfone uses subcritical water and is not suitable for large-scale implementation. On the other hand, as a related reaction, a substitution reaction of a methoxy group with an amino group in a para-methoxy-substituted benzophenone, which is one of the structural units of polyether ether ketone, using an organic superbase catalyst and an arylamine is known (see Non-Patent Document 7), but there have been no examples of this method being applied to the depolymerization of polysulfone, polyphenylsulfone, polyethersulfone, etc.

[0004] Therefore, if we continue as we are, not only will this place a heavy burden on the environment, but we will also be unable to cope with a future in which the use of non-recyclable plastics will be banned. Furthermore, because these super engineering plastics are high-priced products, disposing of them will in itself involve a large economic loss. Therefore, the development of a new method for depolymerizing super engineering plastics is desired.

[0005] International Publication No. 2008 / 004642 Japanese Patent Application Laid-Open No. 2013-249324

[0006] Yu, ZL; Miao, GX; Chen, YR Macromol Chem Phys 1996, 197, 4061.Wang, SJ; Bian, SG; Yan, H.; Xiao, M.; Meng, YZJ App. Poly. Sci. 2008, 110, 4049.Lian, Z.; Bhawal, BN; Morandi, B. Science 2017, 356, 1059.Minami, Y.; Matsuyama, N.; Matsuo, Y.; Tamura, M.; Sato, K.; Nakajima, Y. Synthesis 2021, 53, 3351.Delcaillau, T.; Woenckhaus-Alvarez, A.; Morandi, B. Org. Lett. 2021, 23, 7018.Minami, Y.; Matsuyama, N.; Takeichi, Y.; Watanabe, R.; Mathew, S.; Nakajima, Y. Communications Chemistry, 2023, 6, 14. DOI: 10.1038 / s42004-023-00814-8. Shigeno, M.; Hayashi, K.; Nozawa-Kumada, K.; Kondo, Y. Org. Lett. 2019, 21, 5505.

[0007] An object of the present invention is to provide a novel method for depolymerizing (decomposing) super engineering plastics such as polysulfone.

[0008] In order to solve the above problems, the present invention employs the following configuration: [1] A compound represented by the following general formula (1): (In the formula, n １ is an integer of 2 or more (preferably, 10 to 200); Z １１ and Z １２ are each independently a group other than a hydrogen atom; m １１ and m １２ are each independently an integer of 0 to 4, and m １１ When n is an integer of 1 or more, １ ×m１１ Z １１ may be the same or different, m １２ When n is an integer of 1 or more, １ ×m １２ Z １２ may be the same or different; Ar １ is represented by the following general formula (91), (92) or (93):

[0009] (In the formula, X １１ , X １２ , X ２１ , X ３１ and X ３２ are each independently a group other than a hydrogen atom; １１ , l １２ , l ２１ , l ３１ and l ３２ are each independently an integer of 0 to 4, １１ When n is an integer of 1 or more, １ ×l １１ X of pieces １１ may be the same or different, １２ When n is an integer of 1 or more, １ ×l １２ X of pieces １２ may be the same or different, ２１ When n is an integer of 1 or more, １ ×l ２１ X of pieces ２１ may be the same or different, ３１ When n is an integer of 1 or more, １ ×l ３１ X of pieces ３１ may be the same or different, ３２ When n is an integer of 1 or more, １ ×l ３２ X of pieces ３２ may be the same or different.) and the bonds marked with * and the bonds marked with ** in the general formulas (91), (92) and (93) are respectively formed with the oxygen atom in the general formula (1).) and a first compound represented by the following general formula (8) R ８-SH (8) (wherein, R ８ is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, a central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0010] [2] The following general formula (2) (In the formula, n ２ is an integer of 2 or more (preferably, 10 to 200); Z ２１ , Z ２２ and Z ２３ are each independently a group other than a hydrogen atom; m ２１ , m ２２ and m ２３ are each independently an integer of 0 to 4, and m ２１ When n is an integer of 1 or more, ２ ×m ２１ Z ２１ may be the same or different, m ２２ When n is an integer of 1 or more, ２ ×m ２２ Z ２２ may be the same or different, m ２３ When n is an integer of 1 or more, ２ ×m ２３ Z ２３ may be the same or different), and a third compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, a central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0011] [3] The following general formula (4): (In the formula, n ４ is an integer of 2 or more (preferably, 10 to 200); Z ４１ and Z ４２ are each independently a group other than a hydrogen atom; m ４１ and m ４２ are each independently an integer of 0 to 4, and m ４１ When n is an integer of 1 or more, ４ ×m ４１ Z ４１ may be the same or different, m ４２ When n is an integer of 1 or more, ４ ×m ４２ Z ４２ may be the same or different), in the presence of a base, a compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, a central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0012] [4] The method for decomposing a compound according to any one of [1] to [3], wherein at least a phosphazene base or sodium tert-butoxide is used as the base.

[0013] [5] The method for decomposing a compound according to any one of [1] to [3], wherein the compound represented by general formula (8) is one or more selected from the group consisting of alkyl mercaptans having 1 to 15 carbon atoms, aryl mercaptans having 6 to 12 carbon atoms, aralkyl mercaptans having 7 to 14 carbon atoms, halogenated alkyl mercaptans having 1 to 15 carbon atoms, halogenated aryl mercaptans having 6 to 12 carbon atoms, hydroxyalkyl mercaptans having 1 to 15 carbon atoms, polymercaptoalkanes having 1 to 15 carbon atoms, (mercaptoalkyl)trialkoxysilanes having 4 to 15 carbon atoms, and alkoxycarbonylalkanethiols having 3 to 15 carbon atoms.

[0014] [6] The method for decomposing a compound according to any one of [1] to [3], wherein a dehydrating agent is further used in the decomposition step.

[0015] [7] The method for decomposing a compound according to any one of [1] to [3], wherein the hydroxide is an alkali metal hydroxide.

[0016] [8] The method for decomposing a compound according to [6], wherein the dehydrating agent is one or more selected from the group consisting of sodium hydride, potassium hydride, calcium hydride, calcium oxide, cesium chloride, calcium chloride, magnesium sulfate, and zeolite.

[0017] [9] A compound represented by the following general formula (11), obtained by the method for decomposing a compound according to any one of [1] to [3]: (In the formula, Z １１ , Z １２ , m １１ and m １２ is the same as above.) a compound represented by the formula (I) or a salt thereof,

[0018] The following general formula (121) (In the formula, X １１ , X １２ , l １１ and l １２ is the same as above.) and salts thereof,

[0019] The following general formula (122) (In the formula, X ２１ and l ２１ are the same as above.) and salts thereof,

[0020] The following general formula (123) (In the formula, X ３１ , X ３２ , l ３１ and l ３２ is the same as above.) and salts thereof,

[0021] The following general formula (21) (In the formula, Z ２１ , Z ２２ , m ２１ and m ２２ is the same as above.) or a salt thereof;

[0022] The following general formula (22) (In the formula, Z ２３ and m ２３ is the same as above.) and salts thereof,

[0023] Or the following general formula (41) (In the formula, Z ４１ , Z ４２ , m ４１ and m ４２ is the same as above.) and salts thereof, to obtain an ether compound by etherifying one or more phenolic hydroxyl groups or groups in which the phenolic hydroxyl groups form salts.

[0024]

[12] The following general formula (3): (In the formula, n ３ is an integer of 2 or more (preferably, 10 to 200); Z ３１ , Z ３２ , Z ３３ , Z ３４ and Z ３５ are each independently a group other than a hydrogen atom; m ３１ and m ３２ are each independently an integer of 0 to 3, and m ３３ , m ３４ and m ３５ are each independently an integer of 0 to 4, and m ３１ When n is an integer of 1 or more, ３ ×m ３１ Z ３１ may be the same or different, m ３２ When n is an integer of 1 or more, ３ ×m ３２ Z ３２ may be the same or different, m ３３ When n is an integer of 1 or more, ３ ×m ３３ Z ３３ may be the same or different, m ３４ When n is an integer of 1 or more, ３ ×m ３４ Z ３４ may be the same or different, m ３５ When n is an integer of 1 or more, ３ ×m ３５ Z ３５may be the same or different), and a fifth compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８ is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, a central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0025] According to the present invention, a novel method for depolymerizing (decomposing) super engineering plastics such as polysulfone is provided.

[0026] In Example 1 of Embodiment 2, the reaction mixture １ 1 H NMR analysis results of the reaction mixture in Example 2 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 3 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 4 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 5 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 6 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 7 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 8 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 9 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 10 of Embodiment 2. １ 1 H NMR analysis results of the reaction mixture in Example 11 of Embodiment 2. １1 H NMR analysis results of the reaction mixture in Example 12 of Embodiment 2. １ 1 H NMR analysis results of bisphenol S in Example 13 of Embodiment 2. １ 1 H NMR analysis results of bisphenol A in Example 13 of Embodiment 2. １ 1 H NMR analysis results of the target product in Example 14 of Embodiment 2. １ 1 H NMR analysis results of the target product in Example 15 of Embodiment 2. １ 1 H NMR analysis results of the target product in Example 16 of Embodiment 2. １ 1 H NMR analysis results of bisphenol S in Example 17 of Embodiment 2. １ 1 H NMR analysis results of the target product in Example 18 of Embodiment 2. １ 1 H NMR analysis results of bisphenol S in Example 19 of Embodiment 2. １ 1 H NMR analysis results of 4,4′-dihydroxybiphenyl in Example 19 of Embodiment 2. １ 1 H NMR analysis results of bisphenol S in Example 20 of Embodiment 2. １ 1 H NMR analysis results of the target product in Example 21 of Embodiment 2. １ 1 H NMR analysis results of 4-((4-(4-Hydroxyphenoxy)phenyl)sulfonyl)phenol in Example 22 of Embodiment 2. １ 1 H NMR analysis results of 4,4′-dihydroxybenzophenone in Example 23 of Embodiment 2. １ 1 H NMR analysis results of 4-((4-(4-Hydroxyphenoxy)phenyl)sulfonyl)phenol in Example 23 of Embodiment 2. １ 1 H NMR analysis results.

[0027] Hereinafter, embodiments of the compound decomposition method according to the present invention will be described. Note that the present invention is not limited to the following embodiments. The contents of Japanese Patent Application No. 2023-016683 and Japanese Patent Application No. 2023-016684 are incorporated herein by reference as part of this specification.

[0028] In this specification, the concentration unit "M" means "mol / L."

[0029] In this specification, when a compound is represented by a general formula or other formula (a non-generalized formula, sometimes simply referred to as a "formula" in this specification), a symbol may be assigned to the general formula or other formula. In such cases, the compound may be given a name with the symbol attached. For example, in this specification, a compound represented by the general formula (1) described below may be referred to as "compound (1)."

[0030] (Embodiment 1) Method for Depolymerizing a Compound <<Depolymerization Method (i)>> A method for depolymerizing (decomposing) a compound according to one embodiment of the present invention is a method for decomposing a compound represented by the following general formula (1): (In the formula, n １ is an integer of 2 or more (preferably, 10 to 200); Z １１ and Z １２ are each independently a group other than a hydrogen atom; m １１ and m １２ are each independently an integer of 0 to 4, and m １１ When n is an integer of 1 or more, １ ×m １１ Z １１ may be the same or different, m １２ When n is an integer of 1 or more, １ ×m １２ Z １２ may be the same or different; Ar １ is represented by the following general formula (91), (92) or (93):

[0031] (In the formula, X １１ , X １２ , X ２１ , X ３１ and X３２ are each independently a group other than a hydrogen atom; １１ , l １２ , l ２１ , l ３１ and l ３２ are each independently an integer of 0 to 4, １１ When n is an integer of 1 or more, １ ×l １１ X of pieces １１ may be the same or different, １２ When n is an integer of 1 or more, １ ×l １２ X of pieces １２ may be the same or different, ２１ When n is an integer of 1 or more, １ ×l ２１ X of pieces ２１ may be the same or different, ３１ When n is an integer of 1 or more, １ ×l ３１ X of pieces ３１ may be the same or different, ３２ When n is an integer of 1 or more, １ ×l ３２ X of pieces ３２ may be the same or different.) and the bonds marked with * and ** in the general formulae (91), (92) and (93) are formed with respect to the oxygen atom in the general formula (1).) (compound (1)) is treated with a compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0032] (In the formula, Z １１ , Z １２ , m １１ , m １２ and R ８ are the same as above.) (hereinafter, this specification may be referred to as "compound (18)") and a compound represented by the following general formula (121), (122) or (123): (In the formula, X １１ , X １２ , X ２１ , X ３１ , X ３２ , l １１ , l １２ , l ２１ , l ３１ and l ３２ are the same as above.) (Herein, these may be referred to as “compound (121),” “compound (122),” and “compound (123),” respectively). In this specification, the method for depolymerizing (decomposing) a compound of this embodiment may be referred to as “depolymerization method (i).”

[0033] The depolymerization method of this embodiment (depolymerization method (i)) is a novel method for depolymerizing compound (1) including super engineering plastics.

[0034] Compound (1) has an electron-withdrawing sulfonyl group (—SO ２-)-bonded benzene ring skeleton and an electron-deficient aromatic cyclic group. In the depolymerization method (i), compound (1) has such properties and is depolymerized (decomposed) by compound (8) in the coexistence of a base. Then, compound (121), compound (122), or compound (123) is obtained as the depolymerized product, and compound (18), a thioether compound, is obtained depending on the structure of compound (8).

[0035] The Ar １ is a group represented by the general formula (91), the compound (1) includes polysulfone (sometimes referred to as "PSU" in this specification) and its derivatives.

[0036] The Ar １ In the case where is a group represented by the general formula (92), the compound (1) includes polyether ether sulfone (sometimes referred to as "PEES" in this specification) and its derivatives.

[0037] The Ar １ In the case where is a group represented by the general formula (93), the compound (1) includes polyphenylsulfone (sometimes referred to as "PPSU" in this specification) and its derivatives.

[0038] In this specification, when a structure in which one or more hydrogen atoms in a certain specific compound are substituted with a group other than a hydrogen atom is assumed, the compound having such a substituted structure is referred to as a "derivative" of the above-mentioned specific compound.

[0039] In this specification, unless otherwise specified, the term "group" includes not only an atomic group formed by bonding multiple atoms but also a single atom.

[0040] Ar １ is a group represented by the general formula (91), the depolymerization method (i) is a method for depolymerizing a group represented by the following general formula (1-1):

[0041] (In the formula, n １ , Z １１ , Z １２ , m １１ , m １２, X １１ , X １２ , l １１ and l １２ is the same as above.) in the presence of a base, ８ -SH (8) (wherein, R ８ is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0042] (In the formula, Z １１ , Z １２ , m １１ , m １２ and R ８ are the same as above.) and a compound (compound (18)) represented by the following general formula (121):

[0043] (In the formula, X １１ , X １２ , l １１ and l １２ is the same as above.) (compound (121))

[0044] Ar １ is a group represented by the general formula (92), the depolymerization method (i) is a method for depolymerizing a group represented by the following general formula (1-2): (In the formula, n １ , Z １１ , Z １２ , m １１ , m １２ , X ２１ and l ２１ is the same as above.) in the presence of a base, ８ -SH (8) (wherein, R ８is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0045] (In the formula, Z １１ , Z １２ , m １１ , m １２ and R ８ are the same as above.) and a compound (compound (18)) represented by the following general formula (122):

[0046] (In the formula, X ２１ and l ２１ is the same as above.) (compound (122))

[0047] Ar １ is a group represented by the general formula (93), the depolymerization method (i) is a method for depolymerizing a group represented by the following general formula (1-3): (In the formula, n １ , Z １１ , Z １２ , m １１ , m １２ , X ３１ , X ３２ , l ３１ and l ３２ is the same as above.) in the presence of a base, ８ -SH (8) (wherein, R ８is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0048] (In the formula, Z １１ , Z １２ , m １１ , m １２ and R ８ is the same as above.) and a compound (compound (18)) represented by the following general formula (123):

[0049] (In the formula, X ３１ , X ３２ , l ３１ and l ３２ is the same as above.) (compound (123))

[0050] <Compound (1)> Compound (1) is the target of depolymerization in the depolymerization method (i).

[0051] In general formula (1), n １ is the number of repeating units, which defines the molecular size of compound (1), and is an integer of 2 or more.

[0052] n １ However, for example, compound (1) having a molecular weight of 10 to 200 is suitable as a high-molecular-weight super engineering plastic such as polysulfone (PSU), polyether ether sulfone (PEES), or polyphenyl sulfone (PPSU), which are difficult to depolymerize by conventional methods and are particularly suitable as targets for depolymerization method (i).

[0053] In general formula (1), Z １１ and Z １２are each independently a group other than a hydrogen atom (sometimes referred to as a "substituent" in this specification). １１ and Z １２ may be the same as or different from each other.

[0054] Z １１ and Z １２ Examples of the (substituent) include an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, and a fluorine atom.

[0055] Z １１ and Z １２ The alkyl group in may be linear, branched, or cyclic, and may have both a chain structure (linear or branched) and a cyclic structure. In this specification, an alkyl group having a cyclic structure is considered to be a cyclic alkyl group regardless of whether or not it further has a chain structure. The cyclic structure in a cyclic alkyl group (an alkyl group having a cyclic structure but not a chain structure, and an alkyl group having both a cyclic structure and a chain structure) may be either monocyclic or polycyclic.

[0056] Z １１ and Z １２ The alkyl group preferably has 1 to 15 carbon atoms.

[0057] Z １１ and Z １２Among the alkyl groups in the above, examples of the chain (linear or branched) alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a 1-methylbutyl group, an n-hexyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, an n-heptyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, an n-heptyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,3-dimethylbutyl ...

[0033] Examples of the alkyl group include linear alkyl groups having 1 to 15 carbon atoms, such as an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a 2,2-dimethylpentyl group, a 2,3-dimethylpentyl group, a 2,4-dimethylpentyl group, a 3,3-dimethylpentyl group, a 3-ethylpentyl group, a 2,2,3-trimethylbutyl group, an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a 3,7-dimethyloctyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group.

[0058] Z １１ and Z １２ Among the alkyl groups in the above formula, examples of the cyclic alkyl group (an alkyl group having a monocyclic or polycyclic structure) include cyclic alkyl groups having 3 to 15 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a norbornyl group, an isobornyl group, a 1-adamantyl group, a 2-adamantyl group, a tricyclodecyl group, and cyclopropylmethyl.

[0059] Z １１ and Z １２ The alkyl group in the formula (I) may be, for example, any of an alkyl group having 1 to 10 carbon atoms (a linear alkyl group having 1 to 10 carbon atoms or a cyclic alkyl group having 3 to 10 carbon atoms), an alkyl group having 1 to 8 carbon atoms (a linear alkyl group having 1 to 8 carbon atoms or a cyclic alkyl group having 3 to 8 carbon atoms), an alkyl group having 1 to 6 carbon atoms (a linear alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms), and an alkyl group having 1 to 3 carbon atoms.

[0060] Z １１ and Z １２The alkylcarbonylamino group (general formula: —NH—C(═O)—R ０１ (In the formula, R ０１ is an alkyl group.)) includes, for example, the above-mentioned Z １１ and Z １２ and monovalent groups having a structure in which a carbon atom having a free valence in the alkyl group is bonded to a carbon atom in a carbonylamino group (—NH—C(═O)—).

[0061] An example of the alkylcarbonylamino group is a methylcarbonylamino group (—NH—C(═O)—CH ３ ) and the like, but are not limited to these.

[0062] Z １１ and Z １２ The alkylcarbonylamino group in the formula (I) preferably has 2 to 16 carbon atoms.

[0063] Z １１ and Z １２ Examples of the fluorinated alkyl group in １１ and Z １２ and monovalent groups having a structure in which one or more hydrogen atoms (—H) in the alkyl group are substituted with fluorine atoms (—F).

[0064] In the fluorinated alkyl group, the number of fluorine atoms depends on the number of carbon atoms in the fluorinated alkyl group and is not particularly limited, and may be, for example, 1 to 3. The fluorinated alkyl group may be, for example, a perfluoroalkyl group (a monovalent group having a structure in which all hydrogen atoms in an alkyl group are substituted with fluorine atoms) such as a trifluoromethyl group.

[0065] Z １１ and Z １２ The fluorinated alkyl group preferably has 1 to 15 carbon atoms.

[0066] In general formula (1), m １１ is a Z bonded to one benzene ring skeleton. １１ The number of m １２ Is Z １１Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which １２ The number of m １１ and m １２ are each independently an integer of 0 to 4. That is, m １１ and m １２ may be the same as or different from each other.

[0067] Compound (1) has n １ ×m １１ Z １１ and m １１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×m １１ Z １１ may be the same or different. １１ is an integer equal to or greater than 1, １ ×m １１ Z １１ may all be the same, may all be different, or may only be partially the same.

[0068] Z １２ The same applies to the case where compound (1) has n １ ×m １２ Z １２ and m １２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×m １２ Z １２ may be the same or different. １２ is an integer equal to or greater than 1, １ ×m １２ Z １２ may all be the same, may all be different, or may only be partially the same.

[0069] In general formula (1), Ar １ is a group represented by the general formula (91), a group represented by the general formula (92), or a group represented by the general formula (93).

[0070] In these groups, the bond marked with * is formed with one of the oxygen atoms that is not bonded to the sulfur atom (S) in general formula (1), and the bond marked with ** is formed with the other oxygen atom that is not bonded to the sulfur atom in general formula (1).

[0071] In the general formula (91), X １１ and X １２ are each independently a group (substituent) other than a hydrogen atom. １１ and X １２ may be the same as or different from each other.

[0072] X １１ and X １２ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0073] In general formula (91), l １１ is an X bonded to one benzene ring skeleton. １１ is the number of １２ is X １１ X bonded to another benzene ring skeleton different from the benzene ring skeleton to which １２ is the number of １１ and l １２ are each independently an integer of 0 to 4. That is, l １１ and l １２ may be the same as or different from each other.

[0074] Compound (1) has n １ ×l １１ X of pieces １１ and l １１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l １１ X of pieces １１ may be the same or different from each other. １１ is an integer equal to or greater than 1, １ ×l １１ X of pieces １１may all be the same, may all be different, or may only be partially the same.

[0075] X １２ The same applies to the case where compound (1) has n １ ×l １２ X of pieces １２ and l １２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l １２ X of pieces １２ may be the same or different from each other. １２ is an integer equal to or greater than 1, １ ×l １２ X of pieces １２ may all be the same, may all be different, or may only be partially the same.

[0076] In general formula (91), l １１ and l １２ may be, for example, independently any of 0 to 3, 0 to 2, 0 to 1, and 0.

[0077] A preferred example of the group represented by general formula (91) is l １１ and l １２ is 0 (i.e., X １１ and X １２ (not having) groups.

[0078] In the general formula (92), X ２１ is a group (substituent) other than a hydrogen atom.

[0079] X ２１ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0080] In general formula (92), l ２１ is an X bonded to one benzene ring skeleton. ２１ and is an integer from 0 to 4.

[0081] Compound (1) has n１ ×l ２１ X of pieces ２１ and l ２１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l ２１ X of pieces ２１ may be the same or different from each other. ２１ is an integer equal to or greater than 1, １ ×l ２１ X of pieces ２１ may all be the same, may all be different, or may only be partially the same.

[0082] In general formula (92), l ２１ may be, for example, 0 to 3, 0 to 2, 0 to 1, or 0.

[0083] A preferred example of the group represented by the general formula (92) is l ２１ is 0 (i.e., X ２１ (not having) groups.

[0084] In the general formula (93), X ３１ and X ３２ are each independently a group (substituent) other than a hydrogen atom. ３１ and X ３２ may be the same as or different from each other.

[0085] X ３１ and X ３２ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0086] In general formula (93), l ３１ is an X bonded to one benzene ring skeleton. ３１ is the number of ３２ is X ３１ X bonded to another benzene ring skeleton different from the benzene ring skeleton to which ３２ is the number of ３１ and l ３２are each independently an integer of 0 to 4. That is, l ３１ and l ３２ may be the same as or different from each other.

[0087] Compound (1) has n １ ×l ３１ X of pieces ３１ and l ３１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l ３１ X of pieces ３１ may be the same or different from each other. ３１ is an integer equal to or greater than 1, １ ×l ３１ X of pieces ３１ may all be the same, may all be different, or may only be partially the same.

[0088] X ３２ The same applies to the case where compound (1) has n １ ×l ３２ X of pieces ３２ and l ３２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l ３２ X of pieces ３２ may be the same or different from each other. ３２ is an integer equal to or greater than 1, １ ×l ３２ X of pieces ３２ may all be the same, may all be different, or may only be partially the same.

[0089] In general formula (93), l ３１ and l ３２ may be, for example, independently any of 0 to 3, 0 to 2, 0 to 1, and 0.

[0090] A preferred example of the group represented by general formula (93) is l ３１ and l ３２ is 0 (i.e., X ３１ and X ３２ (not having) groups.

[0091] An example of a preferred compound (1) is Ar １ is any of a group represented by general formula (91), a group represented by general formula (92), and a group represented by general formula (93), m １１ and m １２ is 0 (i.e., Z １１ and Z １２ Compound (1) does not have the formula:

[0092] A more preferred example of the compound (1) is Ar １ is a group represented by general formula (91), and l １１ and l １２ is 0, and m １１ and m １２ is 0.

[0093] Other examples of more preferred compounds (1) include Ar １ is a group represented by general formula (92), and l ２１ is 0, and m １１ and m １２ is 0.

[0094] Further examples of more preferred compounds (1) include Ar １ is a group represented by general formula (93), and l ３１ and l ３２ is 0, and m １１ and m １２ is 0.

[0095] However, compound (1) is not limited to these.

[0096] The compound (1) to be depolymerized may be reinforced with fibers. That is, in the depolymerization method (i), the compound (1) reinforced with fibers can be depolymerized.

[0097] Examples of the fiber-reinforced compound (1) include a carbon fiber-reinforced compound (1) and a glass fiber-reinforced compound (1).

[0098] In the fiber-reinforced compound (1) (referred to in this paragraph as "fiber-reinforced resin"), the ratio of the content of compound (1) to the total mass of the fiber-reinforced compound (1) (mass of compound (1) contained in the fiber-reinforced resin / total mass of the fiber-reinforced resin) × 100) is preferably 10 to 90 mass%, and may be, for example, any of 10 to 70 mass%, 10 to 50 mass%, and 10 to 30 mass%, or any of 30 to 90 mass%, 50 to 90 mass%, and 70 to 90 mass%, or may be 30 to 70 mass%. When this ratio is equal to or greater than the lower limit, the yield of compound (18) and compound (121), compound (122), or compound (123) is increased. When this ratio is equal to or less than the upper limit, the versatility of the fiber-reinforced compound (1) is increased.

[0099] The hydrogen atom in one (1) or both (2) hydroxyl groups (-OH, hydroxyl groups at one or both ends in general formula (1)) in compound (1) may be substituted with a group other than a hydrogen atom (hereinafter represented by the symbol "M") to form a group represented by the formula "-OM". That is, compound (1) may be a salt. The formula "-OM" may be, for example, a group represented by the formula "-O － M ＋ " can also be expressed as ".

[0100] When the hydrogen atoms of both hydroxyl groups in compound (1) are substituted with the above M, these two Ms may be the same or different.

[0101] Examples of M include those which serve as counter cations, and may be metal atoms (salts of compound (1) may be alkoxides). ＋ The cations include counter cations, which may be, for example, phosphazenium cations.

[0102] <Base> The base promotes the depolymerization of compound (1).

[0103] The base may be either an inorganic base (basic inorganic compound) or an organic base (basic organic compound).

[0104] Examples of the inorganic base include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; carbonates (alkali metal carbonates) such as potassium carbonate and cesium carbonate; and phosphates (trialkali metal phosphates) such as tripotassium phosphate.

[0105] Examples of the organic base include alkali metal tert-butoxides such as lithium tert-butoxide, sodium tert-butoxide, and potassium tert-butoxide; alkali metal bistrimethylsilylamides such as lithium bistrimethylsilylamide, sodium bistrimethylsilylamide, and potassium bistrimethylsilylamide; diazabicycloundecene (DBU); and phosphazene base P ４ -t-Bu (also known as 1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylideneamino]-2λ ５ , 4λ ５ -catenated (phosphazene)), phosphazene base P ２ -t-Bu (also known as 1-tert-butyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ５ , 4λ ５ -catenated (phosphazene)), phosphazene base P １ -t-Bu (also known as tert-butylimino-tris(dimethylamino)phosphorane), phosphazene base P ４ -t-Oct (also known as 1-tert-octyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphoranylideneamino]-2λ ５ , 4λ ５ -catenated (phosphazene)), phosphazene base P ２ -Et (also known as 1-ethyl-2,2,4,4,4-pentakis(dimethylamino)-2λ ５ , 4λ ５ -catenadi(phosphazene)), phosphazene base P1-t-Bu-tris(tetramethylene) (also known as tert-butylimino-tri(pyrrolidino)phosphorane), and the like.

[0106] The structures of representative phosphazene bases are shown below. The base used in the depolymerization step may be one type only, or two or more types may be used. When two or more types are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0107] For example, when two or more bases are used, two or more inorganic bases may be used without using an organic base, two or more organic bases may be used without using an inorganic base, or one or more inorganic bases and one or more organic bases may be used together.

[0108] The base used in the depolymerization step is preferably one or more selected from the group consisting of a phosphazene base, a carbonate, and an alkali metal tert-butoxide, and more preferably one or more selected from the group consisting of a phosphazene base, cesium carbonate, sodium tert-butoxide, and potassium tert-butoxide. Use of such a base facilitates the depolymerization of compound (1).

[0109] Among these, since the depolymerization of compound (1) proceeds particularly easily, it is preferable to use at least a phosphazene base or sodium tert-butoxide as the base in the depolymerization step, it is more preferable to use a phosphazene base in combination with an inorganic base or to use sodium tert-butoxide, it is even more preferable to use a phosphazene base in combination with a phosphate or to use sodium tert-butoxide, and it is particularly preferable to use a phosphazene base in combination with tripotassium phosphate or to use sodium tert-butoxide. When sodium tert-butoxide is used, sodium tert-butoxide may be used alone or in combination with another inorganic base as the base.

[0110] In the depolymerization step, the amount (molar number) of the base used is determined based on the repeating unit in the compound (1) (the symbol n １The amount of base used is preferably 4 to 23 mol % relative to the amount (number of moles) of the structural unit (the structural unit marked with ""), and may be, for example, 4 to 13 mol %, 13 to 23 mol %, or 8 to 18 mol %. When the amount of base used is equal to or greater than the lower limit, depolymerization of compound (1) proceeds more easily. When the amount of base used is equal to or less than the upper limit, excessive use of base is suppressed.

[0111] <Compound (8)> Compound (8) is a reaction target of compound (1).

[0112] In general formula (8), R ８ is an alkyl group, an aryl group, or an aralkyl group, and one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group (—OH), a mercapto group (—SH), or a trialkoxysilyl group (these groups may be collectively referred to as “monovalent substituents” in this specification), and the alkyl group, aryl group, or aralkyl group may have one or more trimethylene groups (—CH ２ CH ２ CH ２ -), the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group (-O-C(=O)-) or a carbonyloxy group (-C(=O)-O-) (in this specification, these groups may be collectively referred to as a "divalent substituent").

[0113] R ８ The alkyl group in Z １１ and Z １２ The alkyl group may be the same as the alkyl group described above. ８ The alkyl group in may be any of linear, branched, and cyclic, and may have both a chain structure (linear or branched) and a cyclic structure. The cyclic structure in the cyclic alkyl group (an alkyl group having a cyclic structure but not a chain structure, and an alkyl group having both a cyclic structure and a chain structure) may be either monocyclic or polycyclic.

[0114] R ８The number of carbon atoms in the alkyl group in R is preferably 1 to 15. ８ When is an alkyl group, the compound (8) is preferably an alkyl mercaptan (alkanethiol) having 1 to 15 carbon atoms.

[0115] R ８ is a chain (straight-chain or branched) alkyl group, examples of compound (8) include methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, n-butyl mercaptan, isobutyl mercaptan, sec-butyl mercaptan, tert-butyl mercaptan, n-pentyl mercaptan, isopentyl mercaptan, neopentyl mercaptan, tert-pentyl mercaptan, 1-methylbutyl mercaptan, n-hexyl mercaptan, 2-methylpentyl mercaptan, 3-methylpentyl mercaptan, 2,2-dimethylbutyl mercaptan, 2,3-dimethylbutyl mercaptan, n-heptyl mercaptan, 2-methylhex ...

[0033] Examples of the alkyl mercaptans include chain alkyl mercaptans (alkanethiols) having 1 to 15 carbon atoms, such as octyl mercaptan, 3-methylhexyl mercaptan, 2,2-dimethylpentyl mercaptan, 2,3-dimethylpentyl mercaptan, 2,4-dimethylpentyl mercaptan, 3,3-dimethylpentyl mercaptan, 3-ethylpentyl mercaptan, 2,2,3-trimethylbutyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, 2-ethylhexyl mercaptan, nonyl mercaptan, decyl mercaptan, 3,7-dimethyloctyl mercaptan, undecyl mercaptan, dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, and pentadecyl mercaptan.

[0116] R ８is a cyclic (monocyclic or polycyclic) alkyl group, examples of compound (8) include cyclic alkyl mercaptans (alkanethiols) having 3 to 15 carbon atoms, such as cyclopropyl mercaptan, cyclobutyl mercaptan, cyclopentyl mercaptan, cyclohexyl mercaptan, cycloheptyl mercaptan, cyclooctyl mercaptan, cyclononyl mercaptan, cyclodecyl mercaptan, norbornyl mercaptan, isobornyl mercaptan, 1-adamantyl mercaptan, 2-adamantyl mercaptan, tricyclodecyl mercaptan, and cyclopropylmethyl mercaptan.

[0117] R ８ The alkyl group in the formula (I) may be, for example, any of an alkyl group having 1 to 15 carbon atoms (a linear alkyl group having 1 to 15 carbon atoms or a cyclic alkyl group having 3 to 15 carbon atoms), an alkyl group having 1 to 10 carbon atoms (a linear alkyl group having 1 to 10 carbon atoms or a cyclic alkyl group having 3 to 10 carbon atoms), an alkyl group having 1 to 8 carbon atoms (a linear alkyl group having 1 to 8 carbon atoms or a cyclic alkyl group having 3 to 8 carbon atoms), an alkyl group having 1 to 6 carbon atoms (a linear alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms), and an alkyl group having 1 to 3 carbon atoms.

[0118] R ８ The aryl group in the formula (I) may be either monocyclic or polycyclic.

[0119] R ８ The number of carbon atoms in the aryl group in the formula (I) is preferably 6 to 15, and examples of the aryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a 4-tert-butylphenyl group, and a xylyl group (dimethylphenyl group). Furthermore, one or more hydrogen atoms in these aryl groups may be substituted with one or more hydrogen atoms in the aryl group or Z １１ and Z １２ The aryl group having such a substituent preferably has 6 to 15 carbon atoms.

[0120] R ８The aryl group in the formula (I) more preferably has 6 to 12 carbon atoms.

[0121] R ８ is the aryl group, more specifically, examples of the compound (8) include aryl mercaptans such as phenyl mercaptan, 1-naphthyl mercaptan, 2-naphthyl mercaptan, o-tolyl mercaptan (also known as o-toluenethiol), m-tolyl mercaptan (also known as m-toluenethiol), p-tolyl mercaptan (also known as p-toluenethiol), 4-tert-butylphenyl mercaptan (also known as 4-tert-butylbenzenethiol), and xylyl mercaptan (dimethylphenyl mercaptan). Furthermore, in these aryl mercaptans, one or more hydrogen atoms are replaced by the aryl group or Z １１ and Z １２ Also included are mercaptans having a structure substituted with the above alkyl groups.

[0122] R ８ When is the aryl group, the compound (8) is preferably an aryl mercaptan having 6 to 12 carbon atoms.

[0123] R ８ As the aralkyl group in the above, for example, the above Z １１ and Z １２ In the above, one hydrogen atom bonded to a carbon atom having no free valence in the alkyl group is selected from the group consisting of the above-mentioned R ８ Examples of the monovalent group include a group having a structure substituted with the aryl group shown in the above formula.

[0124] R ８ The number of carbon atoms in the aralkyl group in the formula (I) is preferably 7 to 17, and examples of the aralkyl group include a benzyl group (phenylmethyl group), a 4-tert-butylbenzyl group ((4-tert-butylphenyl)methyl group), a phenethyl group (phenylethyl group), a 4-tert-butylphenethyl group (2-(4-tert-butylphenyl)ethyl group), a 1-naphthylmethyl group, a 2-naphthylmethyl group, an o-tolylmethyl group, an m-tolylmethyl group, a p-tolylmethyl group, and a xylylmethyl group.

[0125] R ８ The aralkyl group in the formula (I) more preferably has 7 to 14 carbon atoms.

[0126] R ８ is the aralkyl group, more specific examples of compound (8) include benzyl mercaptan (also known as phenylmethyl mercaptan), 4-tert-butylbenzyl mercaptan (also known as (4-tert-butylphenyl)methyl mercaptan or (4-tert-butylphenyl)methanethiol), phenethyl mercaptan (also known as 2-phenylethyl mercaptan), 4-tert-butylphenethyl mercaptan (also known as 2-(4-tert-butylphenyl)ethyl mercaptan or 2-(4-tert-butylphenyl)ethanethiol), 1-naphthylmethyl mercaptan, 2-naphthylmethyl mercaptan, o-tolylmethyl mercaptan, m-tolylmethyl mercaptan, p-tolylmethyl mercaptan, and xylylmethyl mercaptan.

[0127] R ８ When is the aralkyl group, compound (8) is more preferably an aralkyl mercaptan having 7 to 14 carbon atoms.

[0128] R ８ Among the monovalent substituents therein, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0129] R ８ In the trialkoxysilyl group which is the monovalent substituent in the above, examples of the alkoxy group constituting the trialkoxysilyl group include the above-mentioned Z １１ and Z １２ and monovalent groups having a structure in which a carbon atom having a free valence in the alkyl group is bonded to an oxygen atom.

[0130] The alkoxy group may be linear, branched, or cyclic, and may have both a chain structure (linear or branched) and a cyclic structure. The cyclic structure in the cyclic alkoxy group (an alkoxy group having a cyclic structure but not a chain structure, and an alkoxy group having both a cyclic structure and a chain structure) may be monocyclic or polycyclic.

[0131] The alkoxy group preferably has 1 to 15 carbon atoms.

[0132] Among the alkoxy groups, examples of the chain (straight-chain or branched-chain) alkoxy groups include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, an isopentyloxy group, a neopentyloxy group, a tert-pentyloxy group, a 1-methylbutyloxy group, an n-hexyloxy group, a 2-methylpentyloxy group, a 3-methylpentyloxy group, a 2,2-dimethylbutyloxy group, a 2,3-dimethylbutyloxy group, an n-heptyloxy group, and a 2-methylhexyloxy group. and linear alkoxy groups having 1 to 15 carbon atoms, such as a 3-methylhexyloxy group, a 2,2-dimethylpentyloxy group, a 2,3-dimethylpentyloxy group, a 2,4-dimethylpentyloxy group, a 3,3-dimethylpentyloxy group, a 3-ethylpentyloxy group, a 2,2,3-trimethylbutyloxy group, an n-octyloxy group, an isooctyloxy group, a 2-ethylhexyloxy group, a nonyloxy group, a decyloxy group, a 3,7-dimethyloctyloxy group, an undecyloxy group, a dodecyloxy group, a tridecyloxy group, a tetradecyloxy group, and a pentadecyloxy group.

[0133] Among the alkoxy groups, examples of the cyclic (monocyclic or polycyclic) alkoxy groups include cyclic alkoxy groups having 3 to 15 carbon atoms, such as a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cycloheptyloxy group, a cyclooctyloxy group, a cyclononyloxy group, a cyclodecyloxy group, a norbornyloxy group, an isobornyloxy group, a 1-adamantyloxy group, a 2-adamantyloxy group, a tricyclodecyloxy group, and a cyclopropylmethyloxy group.

[0134] The alkoxy group may be, for example, any of an alkoxy group having 1 to 15 carbon atoms (a chain-like alkoxy group having 1 to 15 carbon atoms or a cyclic alkoxy group having 3 to 15 carbon atoms), an alkoxy group having 1 to 10 carbon atoms (a chain-like alkoxy group having 1 to 10 carbon atoms or a cyclic alkoxy group having 3 to 10 carbon atoms), an alkoxy group having 1 to 8 carbon atoms (a chain-like alkoxy group having 1 to 8 carbon atoms or a cyclic alkoxy group having 3 to 8 carbon atoms), an alkoxy group having 1 to 6 carbon atoms (a chain-like alkoxy group having 1 to 6 carbon atoms or a cyclic alkoxy group having 3 to 6 carbon atoms), and an alkoxy group having 1 to 3 carbon atoms.

[0135] R ８ In the trialkoxysilyl group which is the monovalent substituent in the above, the three alkoxy groups may be the same as or different from one another. That is, the three alkoxy groups may all be the same as one another, all be different as one another, or only some (two) of the alkoxy groups may be the same as one another. When two or three alkoxy groups are different from one another, the combination of these alkoxy groups is not particularly limited.

[0136] In particular, it is preferable that the three alkoxy groups are all the same, in terms of easier availability or production of compound (8).

[0137] R ８ Preferred examples of the trialkoxysilyl group as the monovalent substituent in the above include a trimethoxysilyl group and a triethoxysilyl group.

[0138] R ８When one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group in the formula (I) are substituted with the monovalent substituent, the substitution position is not particularly limited.

[0139] The number of the hydrogen atoms substituted with the monovalent substituent is not particularly limited as long as it is equal to or less than the number of carbon atoms in the alkyl group, aryl group, or aralkyl group.

[0140] When the monovalent substituent is a hydroxyl group, a mercapto group, or a trialkoxysilyl group, the number of hydrogen atoms substituted with these substituents is preferably 1 to 2, and more preferably 1.

[0141] When the monovalent substituent is a halogen atom, the number of hydrogen atoms substituted with this substituent may be 1 to 2, or may be 3 or more, and all of the hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with halogen atoms. That is, the alkyl group, aryl group, or aralkyl group in which one or more hydrogen atoms are substituted with halogen atoms may be a perhaloalkyl group, perhaloaryl group, or perhaloaralkyl group.

[0142] R ８ is an alkyl group in which one or more hydrogen atoms are substituted with halogen atoms, examples of compound (8) include 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecanethiol, and the like, and halogenated alkyl mercaptans (halogenated alkanethiols) having 1 to 15 carbon atoms are preferred.

[0143] R ８ is an aryl group in which one or more hydrogen atoms are substituted with halogen atoms, examples of compound (8) include 4-chlorophenyl mercaptan (also known as 4-chlorobenzenethiol), and halogenated aryl mercaptans having 6 to 12 carbon atoms are preferred.

[0144] R ８is an alkyl group in which one or more hydrogen atoms are substituted with hydroxyl groups, examples of compound (8) include 2-hydroxyethyl mercaptan (also known as 2-hydroxyethanethiol), and hydroxyalkyl mercaptans (hydroxyalkanethiols) having 1 to 15 carbon atoms are preferred.

[0145] R ８ is an alkyl group in which one or more hydrogen atoms are substituted with a mercapto group, examples of compound (8) include 1,2-dimercaptoethane (also known as 1,2-ethanedithiol), and polymercaptoalkanes having 1 to 15 carbon atoms (alkane polythiols, alkanes having two or more mercapto groups) are preferred.

[0146] R ８ is an alkyl group in which one or more hydrogen atoms are substituted with a trialkoxysilyl group, examples of compound (8) include (3-mercaptopropyl)triethoxysilane (also known as 3-(triethoxysilyl)-1-propanethiol), and preferred are (mercaptoalkyl)trialkoxysilanes having 4 to 15 carbon atoms.

[0147] R ８ The case where the aryl group in the formula (I) has one or more trimethylene groups means, for example, the case where an alkyl group having 3 or more carbon atoms is bonded to the ring skeleton of the aromatic hydrocarbon ring in the aryl group, and this alkyl group has a trimethylene group.

[0148] R ８ The case in which the aralkyl group has one or more trimethylene groups means, for example, either or both of the case in which the alkylene group bonded to the ring skeleton of the aromatic hydrocarbon ring in the aralkyl group has 3 or more carbon atoms and this alkylene group has a trimethylene group, and the case in which an alkyl group having 3 or more carbon atoms is bonded to the ring skeleton of the aromatic hydrocarbon ring in the aralkyl group and this alkyl group has a trimethylene group.

[0149] R ８The alkyl group, aryl group, or aralkyl group in ２ CH ２ CH ２ When the trimethylene group has two methylene groups (-CH ２ -) is a methylene group bonded to

[0150] The phrase "the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group (-O-C(=O)-) or a carbonyloxy group (-C(=O)-O-) (divalent substituent)" means that in the substituted trimethylene group, the bond of the asymmetric group represented by the formula "-C(=O)-O-" may be oriented in either of two directions.

[0151] In this specification, the carbon atom at one end of the trimethylene group may be bonded to a hydrogen atom, that is, the alkyl group, aryl group or aralkyl group may be a group represented by the formula "CH ３ CH ２ CH ２ -" is considered to have a group represented by the formula "CH ３ -OC(=O)-CH ２ -" or a group represented by the formula "CH ３ -C(=O)-O-CH ２ -" may be a group represented by the formula:

[0152] R ８ When the central methylene group in one or more trimethylene groups in the alkyl group, aryl group, or aralkyl group in the formula (I) is substituted with the divalent substituent, the substitution position is not particularly limited.

[0153] The number of methylene groups substituted with the divalent substituent is not particularly limited as long as it is equal to or less than the number of trimethylene groups in the alkyl group, aryl group, or aralkyl group. In particular, the number of methylene groups substituted with the divalent substituent is preferably 1 to 2, and more preferably 1.

[0154] R ８In the case where the central methylene group in one or more trimethylene groups is an alkyl group substituted with the divalent substituent, examples of compound (8) include 1-mercapto-2-methoxycarbonylethane (also known as 2-(methoxycarbonyl)ethanethiol, CH ３ OC(=O)CH ２ CH ２ SH), 1-mercapto-2-methylcarbonyloxyethane (also known as 2-(methylcarbonyloxy)ethanethiol, CH ３ C(=O)OCH ２ CH ２ SH) and the like.

[0155] R ８ is an alkyl group having a divalent substituent, the compound (8) is more preferably an alkoxycarbonylalkanethiol having 3 to 15 carbon atoms.

[0156] The compound (8) used in the depolymerization step may be one type or two or more types, and when two or more types are used, the combination and ratio thereof can be selected arbitrarily depending on the purpose. When two or more types of compound (8) are used, two or more types of compound (18) may be produced.

[0157] In terms of facilitating the depolymerization of compound (1), compound (8) is preferably one or more selected from the group consisting of alkyl mercaptans having 1 to 15 carbon atoms, aryl mercaptans having 6 to 12 carbon atoms, aralkyl mercaptans having 7 to 14 carbon atoms, halogenated alkyl mercaptans having 1 to 15 carbon atoms, halogenated aryl mercaptans having 6 to 12 carbon atoms, hydroxyalkyl mercaptans having 1 to 15 carbon atoms, polymercaptoalkanes having 1 to 15 carbon atoms, (mercaptoalkyl)trialkoxysilanes having 4 to 15 carbon atoms, and alkoxycarbonylalkanethiols having 3 to 15 carbon atoms.

[0158] In the depolymerization step, the amount (molar number) of compound (8) used is determined based on the repeating unit in compound (1) (symbol n in general formula (1)). １The amount of compound (8) used may be, for example, 1.5 to 6 times the molar amount, preferably 2 to 6 times the molar amount, more preferably 2 to 4 times the molar amount, and even more preferably 2 to 3 times the molar amount, relative to the amount (number of moles) of the structural unit (suffixed with " ") (the structural unit marked with " "). When the amount of compound (8) used is equal to or greater than the lower limit, depolymerization of compound (1) proceeds more easily. When the amount of compound (8) used is equal to or less than the upper limit, excessive use of compound (8) is suppressed.

[0159] <Compound (18)> Compound (18) is one of the products obtained by the depolymerization method (i).

[0160] Compound (18) is a derivative of bisphenol S (sometimes referred to as "BPS" in this specification).

[0161] Z in general formula (18) １１ , Z １２ , m １１ and m １２ respectively represent Z in general formula (1). １１ , Z １２ , m １１ and m １２ is the same as

[0162] R in general formula (18) ８ is R in general formula (8) ８ is the same as

[0163] When two or more compounds (8) are used, two R ８ may be the same as one another or may be different from one another.

[0164] <Compound (121)> Compound (121) is a compound obtained by １ is a group represented by general formula (91), the other product of the depolymerization method (i).

[0165] Compound (121) is bisphenol A (sometimes referred to as "BPA" in this specification) and its derivatives.

[0166] X in general formula (121) １１ , X １２ , l １１ and l １２respectively represent X in general formula (91). １１ , X １２ , l １１ and l １２ is the same as

[0167] <Compound (122)> Compound (122) is a compound of Ar １ is a group represented by general formula (92), the other product obtained by depolymerization method (i).

[0168] Compound (122) is hydroquinone (sometimes referred to as "HQ" in this specification) and its derivatives.

[0169] X in general formula (122) ２１ and l ２１ respectively represent X in general formula (92). ２１ and l ２１ Compound (123) is the same as Ar １ is a group represented by general formula (93), the other product obtained by depolymerization method (i).

[0170] Compound (123) is 4,4'-dihydroxybiphenyl (also known as 4,4'-biphenol) (sometimes referred to as "4,4'-DHBP" in this specification) and its derivatives.

[0171] X in general formula (123) ３１ , X ３２ , l ３１ and l ３２ respectively represent X in general formula (93). ３１ , X ３２ , l ３１ and l ３２ <Solvent> In the depolymerization step, it is preferable to further use a solvent. By using a solvent, particularly by dissolving compound (1) in a solvent and carrying out the depolymerization step, the depolymerization of compound (1) can more easily proceed.

[0172] In this specification, unless otherwise specified, the term "solvent" is a concept that encompasses both a component that is liquid at room temperature and that dissolves a solute, and a component that is liquid at room temperature and that functions as a dispersion medium for dispersing a dispersoid. Furthermore, "room temperature" means a temperature that is not particularly cooled or heated, i.e., an ordinary temperature, and examples thereof include a temperature of 15 to 25°C.

[0173] The solvent is preferably an organic solvent.

[0174] Examples of the organic solvent include amides such as 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP); nitriles such as benzonitrile; and ethers (cyclic ethers) such as 1,4-dioxane.

[0175] The solvent used in the depolymerization step may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0176] When a solvent is used in the depolymerization step, the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (1), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.4 to 1.5 L, or 0.6 to 1.5 L, or even 0.4 to 1 L. When the amount of solvent used is equal to or greater than the lower limit, depolymerization of compound (1) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0177] <Other Components> In the depolymerization step, compound (1) may be depolymerized using another component that does not fall into any of compound (1), a base, compound (8), and, if necessary, a solvent, within a range that does not impair the effects of the present invention, or compound (1) may be depolymerized without using the other component.

[0178] The other components can be selected arbitrarily depending on the purpose and are not particularly limited.

[0179] The other component used in the depolymerization step may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0180] When depolymerizing compound (1) in the depolymerization step, the ratio of the total amount (parts by mass) of the base, compound (8), and solvent to the total amount (parts by mass) of the base, compound (8), solvent, and other components (([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used]) / ([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used] + [amount (parts by mass) of other components used]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When this ratio is equal to or greater than the lower limit, the depolymerization of compound (1) proceeds more easily.

[0181] On the other hand, the proportion is 100% by mass or less.

[0182] When the optional component (i.e., the solvent or the other component) is not used when depolymerizing the compound (1), the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0183] <Other Conditions> In the depolymerization step, compound (1), a base, compound (8), and, if necessary, a solvent and, if necessary, the other components are mixed, and the resulting mixture is heated and stirred, thereby depolymerizing compound (1).

[0184] In the depolymerization step, the temperature (reaction temperature) when the mixture is heated and stirred may be room temperature or higher, and is preferably 90° C. or higher, and may be, for example, either 110° C. or higher or 140° C. or higher. The higher the reaction temperature, the more easily the depolymerization of compound (1) proceeds.

[0185] On the other hand, the reaction temperature is preferably 200°C or lower, more preferably 160°C or lower, and may be, for example, 120°C or lower, in terms of suppressing the by-production of impurities.

[0186] In the depolymerization step, the time (reaction time) for heating and stirring the mixture is preferably 1 hour or longer, more preferably 8 hours or longer, and even more preferably 15 hours or longer. When the reaction time is equal to or longer than the lower limit, the yield of compound (18) and compound (121), compound (122), or compound (123) becomes higher.

[0187] On the other hand, the reaction time is preferably 70 hours or less, more preferably 40 hours or less, and even more preferably 20 hours or less, in order to avoid an excessively long reaction time.

[0188] The above reaction times are particularly suitable when the reaction temperature is within the above range.

[0189] In the depolymerization step, the depolymerization of compound (1) may be carried out in an atmosphere of an inert gas such as argon gas, helium gas, or nitrogen gas, or in an air atmosphere.

[0190] In the depolymerization method (i), after completion of the depolymerization step, the resulting reaction mixture can be post-treated as needed by a known method to isolate the target product (product). That is, post-treatment procedures such as filtration, washing, extraction, pH adjustment, dehydration, and concentration can be performed, either alone or in combination, as needed, and the target product can be isolated by concentration, crystallization, reprecipitation, column chromatography, or the like. Furthermore, the isolated target product can be further purified, as needed, by performing one or more operations, either alone or in combination, of crystallization, reprecipitation, column chromatography, extraction, stirring and washing of crystals with a solvent. Alternatively, after completion of the depolymerization step, the resulting reaction mixture can be post-treated as needed, and then used for the next intended application without isolating the target product. For example, the target product can be subjected to the next intended reaction without being isolated.

[0191] The structure of the product obtained by the depolymerization method (i) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0192] <<Depolymerization Method (ii)>> A method for depolymerizing a compound according to one embodiment of the present invention is a method for depolymerizing a compound represented by the following general formula (2): (In the formula, n ２ is an integer of 2 or more (preferably, 10 to 200); Z ２１ , Z ２２ and Z ２３ are each independently a group other than a hydrogen atom; m ２１ , m ２２ and m ２３ are each independently an integer of 0 to 4, and m ２１ When n is an integer of 1 or more, ２ ×m ２１ Z ２１ may be the same or different, m ２２ When n is an integer of 1 or more, ２ ×m ２２ Z ２２ may be the same or different, m ２３ When n is an integer of 1 or more, ２ ×m ２３ Z ２３ may be the same or different.) (hereinafter, may be referred to as “compound (2)”) is reacted with a compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８ is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0193] (In the formula, Z ２１ , Z ２２ , m ２１ , m ２２ and R ８ are the same as above.) (hereinafter, this specification may be referred to as "compound (28)") and a compound represented by the following general formula (22):

[0194] (In the formula, Z ２３ and m ２３ are the same as above.) (herein, this method for depolymerizing a compound of this embodiment may be referred to as "depolymerization method (ii)."

[0195] The depolymerization method of this embodiment (depolymerization method (ii)) is a novel method for depolymerizing compound (2) including super engineering plastics.

[0196] Compound (2) has a benzene ring skeleton to which an electron-withdrawing carbonyl group (—CO—) is bonded and an electron-deficient aromatic cyclic group in its structure. In depolymerization method (ii), compound (2) having such properties is depolymerized by compound (8) in the presence of a base. Then, compound (22) is obtained as the depolymerized product, and compound (28), a thioether compound, is obtained depending on the structure of compound (8).

[0197] The depolymerization method (ii) is the same as the depolymerization method (i), except that the compound (2) is used instead of the compound (1), that is, the target of depolymerization is different.

[0198] The compound (2) includes polyether ether ketone (sometimes referred to as "PEEK" in this specification) and its derivatives.

[0199] <Compound (2)> Compound (2) is the target of depolymerization in the depolymerization method (ii).

[0200] In general formula (2), n ２is the number of repeating units, which defines the molecular size of compound (2), and is an integer of 2 or more.

[0201] n ２ However, for example, compound (2) having a molecular weight of 20 to 200 is suitable as polyether ether ketone (PEEK), a high-molecular-weight super engineering plastic, which is difficult to depolymerize by conventional methods and is particularly suitable as an application target of depolymerization method (ii).

[0202] In general formula (2), Z ２１ , Z ２２ and Z ２３ are each independently a group (substituent) other than a hydrogen atom. ２１ , Z ２２ and Z ２３ may all be the same, may all be different, or only some (any two types) may be the same.

[0203] Z ２１ , Z ２２ and Z ２３ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0204] In general formula (2), m ２１ is a Z bonded to one benzene ring skeleton. ２１ The number of m ２２ Is Z ２１ Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which ２２ The number of m ２３ Is Z ２１ and a benzene ring skeleton to which Z is bonded. ２２ and Z bonded to another benzene ring skeleton different from either of ２３ is the number of

[0205] m ２１ , m ２２ and m ２３ are each independently an integer of 0 to 4. That is, m２１ , m ２２ and m ２３ may all be the same, may all be different, or only some (any two types) may be the same.

[0206] Compound (2) has n ２ ×m ２１ Z ２１ and m ２１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ２ ×m ２１ Z ２１ may be the same or different. ２１ is an integer equal to or greater than 1, ２ ×m ２１ Z ２１ may all be the same, may all be different, or may only be partially the same.

[0207] Z ２２ The same applies to the case where compound (2) has n ２ ×m ２２ Z ２２ and m ２２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ２ ×m ２２ Z ２２ may be the same or different. ２２ is an integer equal to or greater than 1, ２ ×m ２２ Z ２２ may all be the same, may all be different, or may only be partially the same.

[0208] Z ２３ The same applies to the case where compound (2) has n ２ ×m ２３ Z ２３ and m ２３ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ２ ×m ２３ Z ２３ may be the same or different.２３ is an integer equal to or greater than 1, ２ ×m ２３ Z ２３ may all be the same, may all be different, or may only be partially the same.

[0209] An example of a preferred compound (2) is m ２１ , m ２２ and m ２３ is 0 (i.e., Z ２１ , Z ２２ and Z ２３ Compound (2) does not have the formula:

[0210] However, the compound (2) is not limited to these.

[0211] The compound (2) to be depolymerized may be reinforced with fibers, that is, in the depolymerization method (ii), the compound (2) reinforced with fibers can be depolymerized.

[0212] Examples of the fiber-reinforced compound (2) include a carbon fiber-reinforced compound (2) and a glass fiber-reinforced compound (2).

[0213] In the fiber-reinforced compound (2), the ratio of the content of compound (2) to the total mass of the fiber-reinforced compound (2) ([content of compound (2) in fiber-reinforced compound (2) (parts by mass)] / [total mass of fiber-reinforced compound (2) (parts by mass)] × 100) is preferably 10 to 90 mass%, and may be, for example, any one of 10 to 70 mass%, 10 to 50 mass%, and 10 to 30 mass%, or any one of 30 to 90 mass%, 50 to 90 mass%, and 70 to 90 mass%, or may be 30 to 70 mass%. When this ratio is equal to or greater than the lower limit, the yield of compound (28) and compound (22) is increased. When this ratio is equal to or less than the upper limit, the versatility of the fiber-reinforced compound (2) is increased.

[0214] The hydrogen atom in one (one) or both (two) hydroxyl groups (-OH, hydroxyl groups at one or both ends in the general formula (2)) in the compound (2) may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-OM", as in the case of the compound (1) above. － M ＋ In other words, compound (2) may be a salt.

[0215] The manner in which compound (2) forms a salt is the same as the manner in which compound (1) forms a salt. That is, the salt of compound (2) is also formed in the same manner as the salt of compound (1), and is the same as the salt of compound (1) except that the group to which the group represented by the formula "-OM" is bonded is different.

[0216] <Base> The base in the depolymerization method (ii) is the same as the base in the depolymerization method (i).

[0217] The base used in the depolymerization step of the depolymerization method (ii) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0218] For example, when two or more bases are used, two or more inorganic bases may be used without using an organic base, two or more organic bases may be used without using an inorganic base, or one or more inorganic bases and one or more organic bases may be used together.

[0219] The base used in the depolymerization step of the depolymerization method (ii) is preferably one or more selected from the group consisting of a phosphazene base, a carbonate, and an alkali metal tert-butoxide, and more preferably one or more selected from the group consisting of a phosphazene base, cesium carbonate, sodium tert-butoxide, and potassium tert-butoxide. Use of such a base facilitates the depolymerization of compound (2).

[0220] Among these, since the depolymerization of compound (2) proceeds particularly easily, it is preferable to use at least a phosphazene base or sodium tert-butoxide as the base in the depolymerization step, it is more preferable to use a phosphazene base in combination with an inorganic base or to use sodium tert-butoxide, it is even more preferable to use a phosphazene base in combination with a phosphate or to use sodium tert-butoxide, and it is particularly preferable to use a phosphazene base in combination with tripotassium phosphate or to use sodium tert-butoxide. When sodium tert-butoxide is used, sodium tert-butoxide may be used alone or in combination with another inorganic base as the base.

[0221] In the depolymerization step of the depolymerization method (ii), the amount (molar number) of the base used is determined based on the repeating unit in the compound (2) (the symbol n ２ The amount of base used is preferably 4 to 23 mol % relative to the amount (number of moles) of the structural unit (the structural unit marked with ""), and may be, for example, 4 to 13 mol %, 13 to 23 mol %, or 8 to 18 mol %. When the amount of base used is equal to or greater than the lower limit, depolymerization of compound (2) proceeds more easily. When the amount of base used is equal to or less than the upper limit, excessive use of base is suppressed.

[0222] <Compound (8)> The compound (8) in the depolymerization method (ii) is the same as the compound (8) in the depolymerization method (i).

[0223] The compound (8) used in the depolymerization step of the depolymerization method (ii) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof can be selected arbitrarily depending on the purpose. When two or more types of compound (8) are used, two or more types of compound (28) may be produced.

[0224] Preferred compounds (8) in the depolymerization method (ii) include the same compounds as preferred compounds (8) in the depolymerization method (i).

[0225] In the depolymerization step of the depolymerization method (ii), the amount (molar number) of compound (8) used is determined based on the repeating unit in compound (2) (the symbol n ２ The amount of compound (8) used may be, for example, 1.5 to 6 times the molar amount, preferably 2 to 6 times the molar amount, more preferably 2 to 4 times the molar amount, and even more preferably 2 to 3 times the molar amount, relative to the amount (number of moles) of the structural unit (suffixed with " ") (the structural unit marked with " "). When the amount of compound (8) used is equal to or greater than the lower limit, depolymerization of compound (2) proceeds more easily. When the amount of compound (8) used is equal to or less than the upper limit, excessive use of compound (8) is suppressed.

[0226] <Compound (28)> Compound (28) is one of the products obtained by the depolymerization method (ii).

[0227] Compound (28) is a derivative of 4,4'-dihydroxybenzophenone.

[0228] Z in general formula (28) ２１ , Z ２２ , m ２１ and m ２２ respectively represent Z in general formula (2). ２１ , Z ２２ , m ２１ and m ２２ is the same as

[0229] R in general formula (28) ８ is R in general formula (8) ８ is the same as

[0230] When two or more compounds (8) are used, two R ８ may be the same as one another or may be different from one another.

[0231] <Compound (22)> Compound (22) is the other product of the depolymerization method (ii).

[0232] Compound (22) is 1,4-dihydroxybenzene (also known as hydroquinone) and its derivatives.

[0233] Z in general formula (22) ２３ and m ２３ respectively represent Z in general formula (2).２３ and m ２３ is the same as

[0234] <Solvent> In the depolymerization step of the depolymerization method (ii), it is preferable to further use a solvent. By using a solvent, particularly by dissolving compound (2) in a solvent and carrying out the depolymerization step, depolymerization of compound (2) can more easily proceed.

[0235] The solvent in the depolymerization method (ii) is the same as the solvent in the depolymerization method (i).

[0236] The solvent used in the depolymerization step of the depolymerization method (ii) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0237] When a solvent is used in the depolymerization step of the depolymerization method (ii), the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (2), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.4 to 1.5 L, or 0.6 to 1.5 L, or even 0.4 to 1 L. When the amount of solvent used is equal to or greater than the lower limit, the depolymerization of compound (2) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0238] <Other Components> In the depolymerization step of the depolymerization method (ii), the compound (2) may be depolymerized using another component that does not fall under any of the compound (2), the base, the compound (8), and, if necessary, the solvent, within a range that does not impair the effects of the present invention, or the compound (2) may be depolymerized without using the other component.

[0239] The other components in the depolymerization method (ii) are the same as the other components in the depolymerization method (i).

[0240] The other component used in the depolymerization step of the depolymerization method (ii) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0241] When depolymerizing compound (2) in the depolymerization step of depolymerization method (ii), the ratio of the total amount (parts by mass) of the base, compound (8), and solvent to the total amount (parts by mass) of the base, compound (8), solvent, and other components (([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used]) / ([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used] + [amount (parts by mass) of other components used]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When this ratio is equal to or greater than the lower limit, the depolymerization of compound (2) proceeds more easily.

[0242] On the other hand, the proportion is 100% by mass or less.

[0243] When the optional component (i.e., the solvent or the other component) is not used when depolymerizing the compound (2), the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0244] <Other Conditions> In the depolymerization step of the depolymerization method (ii), compound (2), a base, compound (8), and, if necessary, a solvent and, if necessary, the other components are mixed, and the resulting mixture is heated and stirred, thereby enabling depolymerization of compound (2).

[0245] In the depolymerization step of the depolymerization method (ii), the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (2) are the same as the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (1), respectively, in the depolymerization step of the depolymerization method (i).

[0246] In the depolymerization method (ii), after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (i), and the target substance (product) may be isolated, and the isolated target substance may be further purified, if necessary. Alternatively, after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (i), and then used for the next intended application without isolation of the target substance.

[0247] The structure of the product obtained by the depolymerization method (ii) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0248] <<Depolymerization Method (iii)>> A method for depolymerizing a compound according to one embodiment of the present invention is a method for depolymerizing a compound represented by the following general formula (3): (In the formula, n ３ is an integer of 2 or more (preferably, 10 to 200); Z ３１ , Z ３２ , Z ３３ , Z ３４ and Z ３５ are each independently a group other than a hydrogen atom; m ３１ and m ３２ are each independently an integer of 0 to 3, and m ３３ , m ３４ and m ３５ are each independently an integer of 0 to 4, and m ３１ When n is an integer of 1 or more, ３ ×m ３１ Z ３１ may be the same or different, m ３２ When n is an integer of 1 or more, ３ ×m ３２ Z ３２ may be the same or different, m ３３ When n is an integer of 1 or more, ３ ×m ３３ Z ３３ may be the same or different, m ３４ When n is an integer of 1 or more, ３×m ３４ Z ３４ may be the same or different, m ３５ When n is an integer of 1 or more, ３ ×m ３５ Z ３５ may be the same or different.) (hereinafter, may be referred to as “compound (3)”) is reacted with a compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８ is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0249] (In the formula, Z ３１ , Z ３２ , Z ３３ , m ３１ , m ３２ , m ３３ and R ８ are the same as above.) (hereinafter, this specification may be referred to as "compound (38)") and a compound represented by the following general formula (32):

[0250] (In the formula, Z ３４ , Z ３５ , m ３４ and m ３５ are the same as above.) (herein, this method for depolymerizing a compound of this embodiment may be referred to as "depolymerization method (iii)."

[0251] The depolymerization method of this embodiment (depolymerization method (iii)) is a novel method for depolymerizing compound (3) including super engineering plastics.

[0252] Compound (3) has a benzene ring skeleton to which an electron-withdrawing carbonyl group (—CO—) is bonded and an electron-deficient aromatic cyclic group in its structure. In the depolymerization method (iii), compound (3) having such properties is depolymerized by compound (8) in the presence of a base. Compound (32) is obtained as the depolymerized product, and compound (38), a thioether compound, is also obtained depending on the structure of compound (8).

[0253] The depolymerization method (iii) is the same as the depolymerization method (i) except that the compound (3) is used instead of the compound (1), that is, the target of depolymerization is different.

[0254] The compound (3) includes polyetherimide (sometimes referred to as "PEI" in this specification) and its derivatives.

[0255] <Compound (3)> Compound (3) is the target of depolymerization in the depolymerization method (iii).

[0256] In general formula (3), n ３ is the number of repeating units, which defines the molecular size of compound (3), and is an integer of 2 or more.

[0257] n ３ However, for example, compound (3) having a molecular weight of 10 to 100 is suitable as polyetherimide (PEI), a high-molecular-weight super engineering plastic, which is difficult to depolymerize by conventional methods and is particularly suitable as an application target of depolymerization method (iii).

[0258] In general formula (3), Z ３１ , Z ３２ , Z ３３ , Z ３４ and Z ３５ are each independently a group (substituent) other than a hydrogen atom. ３１ , Z ３２ , Z３３ , Z ３４ and Z ３５ may all be the same, may all be different, or only some (any two, three, or four) may be the same.

[0259] Z ３１ , Z ３２ , Z ３３ , Z ３４ and Z ３５ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0260] In general formula (3), m ３１ is a Z bonded to one benzene ring skeleton. ３１ The number of m ３２ Is Z ３１ Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which ３２ The number of m ３３ Is Z ３１ and a benzene ring skeleton to which Z is bonded. ３２ and Z bonded to another benzene ring skeleton different from either of ３３ The number of m ３４ Is Z ３１ and a benzene ring skeleton to which Z is bonded. ３２ and a benzene ring skeleton to which Z is bonded. ３３ and Z bonded to another benzene ring skeleton different from either of ３４ The number of m ３５ Is Z ３１ and a benzene ring skeleton to which Z is bonded. ３２ and a benzene ring skeleton to which Z is bonded. ３３ and a benzene ring skeleton to which Z is bonded. ３４ and Z bonded to another benzene ring skeleton different from either of ３５ is the number of

[0261] m ３１ and m ３２are each independently an integer of 0 to 3. That is, m ３１ and m ３２ may be the same as each other or may be different from each other.

[0262] m ３３ , m ３４ and m ３５ are each independently an integer of 0 to 4. That is, m ３３ , m ３４ and m ３５ may all be the same, may all be different, or only some (any two types) may be the same.

[0263] Compound (3) has n ３ ×m ３１ Z ３１ and m ３１ When n is an integer of 1 or more (i.e., an integer of 1 to 3), ３ ×m ３１ Z ３１ may be the same or different. ３１ is an integer equal to or greater than 1, ３ ×m ３１ Z ３１ may all be the same, may all be different, or may only be partially the same.

[0264] Z ３２ The same applies to the case where compound (3) has n ３ ×m ３２ Z ３２ and m ３２ When n is an integer of 1 or more (i.e., an integer of 1 to 3), ３ ×m ３２ Z ３２ may be the same or different. ３２ is an integer equal to or greater than 1, ３ ×m ３２ Z ３２ may all be the same, may all be different, or may only be partially the same.

[0265] Z ３３The same applies to the case where compound (3) has n ３ ×m ３３ Z ３３ and m ３３ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ３ ×m ３３ Z ３３ may be the same or different. ３３ is an integer equal to or greater than 1, ３ ×m ３３ Z ３３ may all be the same, may all be different, or may only be partially the same.

[0266] Z ３４ The same applies to the case where compound (3) has n ３ ×m ３４ Z ３４ and m ３４ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ３ ×m ３４ Z ３４ may be the same or different. ３４ is an integer equal to or greater than 1, ３ ×m ３４ Z ３４ may all be the same, may all be different, or may only be partially the same.

[0267] Z ３５ The same applies to the case where compound (3) has n ３ ×m ３５ Z ３５ and m ３５ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ３ ×m ３５ Z ３５ may be the same or different. ３５ is an integer equal to or greater than 1, ３ ×m ３５ Z ３５ may all be the same, may all be different, or may only be partially the same.

[0268] An example of a preferred compound (3) is m ３１ , m ３２ , m ３３ , m ３４ and m ３５ is 0 (i.e., Z ３１ , Z ３２ , Z ３３ , Z ３４ and Z ３５ Compound (3) which does not have the formula:

[0269] However, the compound (3) is not limited to these.

[0270] The compound (3) to be depolymerized may be reinforced with fibers, that is, in the depolymerization method (iii), the compound (3) reinforced with fibers can be depolymerized.

[0271] Examples of the fiber-reinforced compound (3) include a carbon fiber-reinforced compound (3) and a glass fiber-reinforced compound (3).

[0272] In the fiber-reinforced compound (3), the ratio of the content of compound (3) to the total mass of the fiber-reinforced compound (3) ([content of compound (3) in fiber-reinforced compound (3) (parts by mass)] / [total mass of fiber-reinforced compound (3) (parts by mass)] × 100) is preferably 10 to 90 mass%, and may be, for example, any one of 10 to 70 mass%, 10 to 50 mass%, and 10 to 30 mass%, or any one of 30 to 90 mass%, 50 to 90 mass%, and 70 to 90 mass%, or may be 30 to 70 mass%. When this ratio is equal to or greater than the lower limit, the yield of compound (38) and compound (32) is increased. When this ratio is equal to or less than the upper limit, the versatility of the fiber-reinforced compound (3) is increased.

[0273] The hydrogen atom in one (one) or both (two) hydroxyl groups (-OH, hydroxyl groups at one or both ends in the general formula (3)) in the compound (3) may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-OM", as in the case of the compound (1) above, or may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-O － M＋ In other words, compound (3) may be a salt.

[0274] The manner in which compound (3) forms a salt is the same as the manner in which compound (1) forms a salt. That is, the salt of compound (3) is also formed in the same manner as the salt of compound (1), and is the same as the salt of compound (1) except that the group to which the group represented by the formula "-OM" is bonded is different.

[0275] <Base> The base in the depolymerization method (iii) is the same as the base in the depolymerization method (i).

[0276] The base to be used in the depolymerization step of the depolymerization method (iii) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0277] For example, when two or more bases are used, two or more inorganic bases may be used without using an organic base, two or more organic bases may be used without using an inorganic base, or one or more inorganic bases and one or more organic bases may be used together.

[0278] The base used in the depolymerization step of the depolymerization method (iii) is preferably one or more selected from the group consisting of a phosphazene base, a carbonate, and an alkali metal tert-butoxide, and more preferably one or more selected from the group consisting of a phosphazene base, cesium carbonate, sodium tert-butoxide, and potassium tert-butoxide. Use of such a base facilitates the depolymerization of compound (3).

[0279] Among these, since the depolymerization of compound (3) proceeds particularly easily, it is preferable to use at least a phosphazene base or sodium tert-butoxide as the base in the depolymerization step, it is more preferable to use a phosphazene base in combination with an inorganic base or to use sodium tert-butoxide, it is even more preferable to use a phosphazene base in combination with a phosphate or to use sodium tert-butoxide, and it is particularly preferable to use a phosphazene base in combination with tripotassium phosphate or to use sodium tert-butoxide. When sodium tert-butoxide is used, sodium tert-butoxide may be used alone or in combination with another inorganic base as the base.

[0280] In the depolymerization step of the depolymerization method (iii), the amount (molar number) of the base used is determined based on the repeating unit in the compound (3) (the symbol n ２ The amount of base used is preferably 4 to 23 mol % relative to the amount (number of moles) of the structural unit (the structural unit marked with ""), and may be, for example, 4 to 13 mol %, 13 to 23 mol %, or 8 to 18 mol %. When the amount of base used is equal to or greater than the lower limit, depolymerization of compound (3) proceeds more easily. When the amount of base used is equal to or less than the upper limit, excessive use of base is suppressed.

[0281] <Compound (8)> The compound (8) in the depolymerization method (iii) is the same as the compound (8) in the depolymerization method (i).

[0282] The compound (8) used in the depolymerization step of the depolymerization method (iii) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof can be selected arbitrarily depending on the purpose. When two or more types of compound (8) are used, two or more types of compound (38) may be produced.

[0283] Preferred compounds (8) in the depolymerization method (iii) include the same as preferred compounds (8) in the depolymerization method (i).

[0284] In the depolymerization step of the depolymerization method (iii), the amount (molar number) of compound (8) used is determined based on the repeating unit in compound (3) (the symbol n ３ The amount of compound (8) used may be, for example, 1.5 to 6 times the molar amount, preferably 2 to 6 times the molar amount, more preferably 2 to 4 times the molar amount, and even more preferably 2 to 3 times the molar amount, relative to the amount (number of moles) of the structural unit (suffixed with " ") (the structural unit marked with " "). When the amount of compound (8) used is equal to or greater than the lower limit, depolymerization of compound (3) proceeds more easily. When the amount of compound (8) used is equal to or less than the upper limit, excessive use of compound (8) is suppressed.

[0285] <Compound (38)> Compound (38) is one of the products obtained by the depolymerization method (iii).

[0286] Compound (38) is a derivative of N,N'-(1,3-phenylene)bis(5-hydroxyphthalimide).

[0287] Z in general formula (38) ３１ , Z ３２ , Z ３３ , m ３１ , m ３２ and m ３３ respectively represent Z in general formula (3). ３１ , Z ３２ , Z ３３ , m ３１ , m ３２ and m ３３ is the same as

[0288] R in general formula (38) ８ is R in general formula (8) ８ is the same as

[0289] When two or more compounds (8) are used, two R ８ may be the same as one another or may be different from one another.

[0290] <Compound (32)> Compound (32) is the other product of the depolymerization method (iii).

[0291] Compound (32) is bisphenol A (BPA) and its derivatives.

[0292] Z in general formula (32) ３４ , Z ３５ , m ３４ and m ３５ respectively represent Z in general formula (3). ３４ , Z ３５ , m ３４ and m ３５ is the same as

[0293] <Solvent> In the depolymerization step of the depolymerization method (iii), it is preferable to further use a solvent. By using a solvent, particularly by dissolving compound (3) in a solvent and carrying out the depolymerization step, depolymerization of compound (3) can more easily proceed.

[0294] The solvent in the depolymerization method (iii) is the same as the solvent in the depolymerization method (i).

[0295] The solvent used in the depolymerization step of the depolymerization method (iii) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0296] When a solvent is used in the depolymerization step of the depolymerization method (ii), the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (3), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.4 to 1.5 L, or 0.6 to 1.5 L, or even 0.4 to 1 L. When the amount of solvent used is equal to or greater than the lower limit, depolymerization of compound (3) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0297] <Other Components> In the depolymerization step of the depolymerization method (iii), the compound (3) may be depolymerized using another component that does not fall under any of the compound (3), the base, the compound (8), and, if necessary, the solvent, within a range that does not impair the effects of the present invention, or the compound (3) may be depolymerized without using the other component.

[0298] The other components in the depolymerization method (iii) are the same as the other components in the depolymerization method (i).

[0299] The other component used in the depolymerization step of the depolymerization method (iii) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0300] When depolymerizing compound (3) in the depolymerization step of depolymerization method (iii), the ratio of the total amount (parts by mass) of the base, compound (8), and solvent to the total amount (parts by mass) of the base, compound (8), solvent, and other components (([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used]) / ([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used] + [amount (parts by mass) of other components used]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When this ratio is equal to or greater than the lower limit, the depolymerization of compound (3) proceeds more easily.

[0301] On the other hand, the proportion is 100% by mass or less.

[0302] When the optional component (i.e., the solvent or the other component) is not used when depolymerizing the compound (3), the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0303] <Other Conditions> In the depolymerization step of the depolymerization method (iii), compound (3), a base, compound (8), and, if necessary, a solvent and, if necessary, the other components are mixed, and the resulting mixture is heated and stirred, thereby enabling depolymerization of compound (3).

[0304] In the depolymerization step of the depolymerization method (iii), the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (3) are the same as the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (1), respectively, in the depolymerization step of the depolymerization method (i).

[0305] In the depolymerization method (iii), after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (i), and the target substance (product) may be isolated, and the isolated target substance may be further purified, if necessary. Alternatively, after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (i), and then used for the next intended application without isolation of the target substance.

[0306] The structure of the product obtained by the depolymerization method (iii) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0307] <<Depolymerization Method (iv)>> A method for depolymerizing (decomposing) a compound according to one embodiment of the present invention comprises decomposing a compound represented by the following general formula (4): (In the formula, n ４ is an integer of 2 or more (preferably, 10 to 200); Z ４１ and Z ４２ are each independently a group other than a hydrogen atom; m ４１ and m ４２ are each independently an integer of 0 to 4, and m ４１ When n is an integer of 1 or more, ４ ×m ４１ Z ４１ may be the same or different, m ４２ When n is an integer of 1 or more, ４ ×m ４２ Z ４２may be the same or different.) (hereinafter, may be referred to as “compound (4)”) is reacted with a compound represented by the following general formula (8): R ８ -SH (8) (wherein, R ８ is an alkyl group, an aryl group, or an aralkyl group, one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group.

[0308] (In the formula, Z ４１ , Z ４２ , m ４１ , m ４２ and R ８ are the same as above.) (herein, this method for depolymerizing a compound of this embodiment may be referred to as "depolymerization method (iv)."

[0309] The depolymerization method of this embodiment (depolymerization method (iv)) is a novel method for depolymerizing compound (4), which includes super engineering plastics.

[0310] Compound (4) has an electron-withdrawing sulfonyl group (—SO ２ Compound (4) has a benzene ring skeleton to which a hydroxyl group (-) is bonded, and has an electron-deficient aromatic cyclic group. In the depolymerization method (iv), compound (4) has such properties and is depolymerized by compound (8) in the presence of a base. Then, compound (48), which is a thioether compound, is obtained as the depolymerized product, depending on the structure of compound (8).

[0311] The depolymerization method (iv) is the same as the depolymerization method (i), except that compound (4) is used instead of compound (1), that is, the target of depolymerization is different.

[0312] The compound (4) includes polyethersulfone (sometimes referred to as "PESU" in this specification) and its derivatives.

[0313] <Compound (4)> Compound (4) is the target of depolymerization in the depolymerization method (iv).

[0314] In general formula (4), n ４ is the number of repeating units, which defines the molecular size of compound (4), and is an integer of 2 or more.

[0315] n ４ However, for example, compound (4) having a molecular weight of 30 to 350 is suitable as polyethersulfone (PESU), a high-molecular-weight super engineering plastic, which is difficult to depolymerize by conventional methods and is particularly suitable as an application target of depolymerization method (iv).

[0316] In general formula (4), Z ４１ and Z ４２ are each independently a group (substituent) other than a hydrogen atom. ４１ and Z ４２ may be the same as each other or may be different from each other.

[0317] Z ４１ and Z ４２ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0318] In general formula (4), m ４１ is a Z bonded to one benzene ring skeleton. ４１ The number of m ４２ Is Z ４１ Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which ４２ is the number of

[0319] m ４１ and m ４２ are each independently an integer of 0 to 4. That is, m ４１ and m ４２ may be the same as each other or may be different from each other.

[0320] Compound (4) has n ４ ×m ４１ Z ４１ and m ４１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ４ ×m ４１ Z ４１ may be the same or different. ４１ is an integer equal to or greater than 1, ４ ×m ４１ Z ４１ may all be the same, may all be different, or may only be partially the same.

[0321] Z ４２ The same applies to the case of compound (4), and compound (4) has n ４ ×m ４２ Z ４２ and m ４２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ４ ×m ４２ Z ４２ may be the same or different. ４２ is an integer equal to or greater than 1, ４ ×m ４２ Z ４２ may all be the same, may all be different, or may only be partially the same.

[0322] An example of a preferred compound (4) is m ４１ and m ４２ is 0 (i.e., Z ４１ and Z ４２ Compound (4) does not have the formula:

[0323] However, compound (4) is not limited to these.

[0324] The compound (4) to be depolymerized may be reinforced with fibers. That is, in the depolymerization method (iv), the compound (4) reinforced with fibers can be depolymerized.

[0325] Examples of the fiber-reinforced compound (4) include a carbon fiber-reinforced compound (4) and a glass fiber-reinforced compound (4).

[0326] In the fiber-reinforced compound (4), the ratio of the content of compound (4) to the total mass of the fiber-reinforced compound (4) ([content of compound (4) in fiber-reinforced compound (4) (parts by mass)] / [total mass of fiber-reinforced compound (4) (parts by mass)] × 100) is preferably 10 to 90 mass%, and may be, for example, any one of 10 to 70 mass%, 10 to 50 mass%, and 10 to 30 mass%, or any one of 30 to 90 mass%, 50 to 90 mass%, and 70 to 90 mass%, or may be 30 to 70 mass%. When this ratio is equal to or greater than the lower limit, the yield of compound (48) is increased. When this ratio is equal to or less than the upper limit, the versatility of the fiber-reinforced compound (4) is increased.

[0327] The hydrogen atom in one (one) or both (two) hydroxyl groups (-OH, hydroxyl groups at one or both ends in the general formula (4)) in the compound (4) may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-OM", as in the case of the compound (1) above. － M ＋ In other words, compound (4) may be a salt.

[0328] The manner in which compound (4) forms a salt is the same as the manner in which compound (1) forms a salt. That is, the salt of compound (4) is also formed in the same manner as the salt of compound (1), and is the same as the salt of compound (1) except that the group to which the group represented by the formula "-OM" is bonded is different.

[0329] <Base> The base in the depolymerization method (iv) is the same as the base in the depolymerization method (i).

[0330] The base to be used in the depolymerization step of the depolymerization method (iv) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0331] For example, when two or more bases are used, two or more inorganic bases may be used without using an organic base, two or more organic bases may be used without using an inorganic base, or one or more inorganic bases and one or more organic bases may be used together.

[0332] The base used in the depolymerization step of the depolymerization method (iv) is preferably one or more selected from the group consisting of a phosphazene base, a carbonate, and an alkali metal tert-butoxide, and more preferably one or more selected from the group consisting of a phosphazene base, cesium carbonate, sodium tert-butoxide, and potassium tert-butoxide. Use of such a base facilitates the depolymerization of compound (4).

[0333] Among these, since the depolymerization of compound (4) proceeds particularly easily, it is preferable to use at least a phosphazene base or sodium tert-butoxide as the base in the depolymerization step, more preferably to use a phosphazene base in combination with an inorganic base or to use sodium tert-butoxide, still more preferably to use a phosphazene base in combination with a phosphate or to use sodium tert-butoxide, and particularly preferably to use a phosphazene base in combination with tripotassium phosphate or to use sodium tert-butoxide. When sodium tert-butoxide is used, sodium tert-butoxide may be used alone or in combination with another inorganic base as the base.

[0334] In the depolymerization step of the depolymerization method (iv), the amount (molar number) of the base used is determined based on the repeating unit in the compound (4) (the symbol n ４The amount of base used is preferably 4 to 23 mol % relative to the amount (number of moles) of the structural unit (the structural unit marked with ""), and may be, for example, 4 to 13 mol %, 13 to 23 mol %, or 8 to 18 mol %. When the amount of base used is equal to or greater than the lower limit, depolymerization of compound (4) proceeds more easily. When the amount of base used is equal to or less than the upper limit, excessive use of base is suppressed.

[0335] <Compound (8)> The compound (8) in the depolymerization method (iv) is the same as the compound (8) in the depolymerization method (i).

[0336] The compound (8) used in the depolymerization step of the depolymerization method (iv) may be one type or two or more types, and when two or more types are used, the combination and ratio thereof can be selected arbitrarily depending on the purpose. When two or more types of compound (8) are used, two or more types of compound (38) may be produced.

[0337] Preferred compounds (8) in the depolymerization method (iv) include the same as preferred compounds (8) in the depolymerization method (i).

[0338] In the depolymerization step of the depolymerization method (iv), the amount (molar number) of compound (8) used is determined based on the repeating unit in compound (4) (the symbol n in general formula (4)). ４ The amount of compound (8) used may be, for example, 1.5 to 6 times the molar amount, preferably 2 to 6 times the molar amount, more preferably 2 to 4 times the molar amount, and even more preferably 2 to 3 times the molar amount, relative to the amount (number of moles) of the structural unit (suffixed with " ") (the structural unit marked with " "). When the amount of compound (8) used is equal to or greater than the lower limit, depolymerization of compound (4) is more likely to proceed. When the amount of compound (8) used is equal to or less than the upper limit, excessive use of compound (8) is suppressed.

[0339] <Compound (48)> Compound (48) is a product obtained by the depolymerization method (iv).

[0340] Compound (48) is a derivative of bisphenol S (BPS).

[0341] Z in general formula (48) ４１ , Z ４２ , m４１ and m ４２ respectively represent Z in general formula (4). ４１ , Z ４２ , m ４１ and m ４２ is the same as

[0342] R in general formula (48) ８ is R in general formula (8) ８ is the same as

[0343] When two or more compounds (8) are used, two R ８ may be the same as one another or may be different from one another.

[0344] <Solvent> In the depolymerization step of the depolymerization method (iv), it is preferable to further use a solvent. By using a solvent, particularly by dissolving compound (4) in a solvent and carrying out the depolymerization step, depolymerization of compound (4) can more easily proceed.

[0345] The solvent in the depolymerization method (iv) is the same as the solvent in the depolymerization method (i).

[0346] The solvent used in the depolymerization step of the depolymerization method (iv) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0347] When a solvent is used in the depolymerization step of the depolymerization method (iv), the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (4), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.4 to 1.5 L, or 0.6 to 1.5 L, or even 0.4 to 1 L. When the amount of solvent used is equal to or greater than the lower limit, depolymerization of compound (4) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0348] <Other Components> In the depolymerization step of the depolymerization method (iv), the compound (4) may be depolymerized using another component that does not fall under any of the compound (4), the base, the compound (8), and, if necessary, the solvent, within a range that does not impair the effects of the present invention, or the compound (4) may be depolymerized without using the other component.

[0349] The other components in the depolymerization method (iv) are the same as the other components in the depolymerization method (i).

[0350] The other component used in the depolymerization step of the depolymerization method (iv) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0351] When depolymerizing compound (4) in the depolymerization step of depolymerization method (iv), the ratio of the total amount (parts by mass) of the base, compound (8), and solvent to the total amount (parts by mass) of the base, compound (8), solvent, and other components (([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used]) / ([amount (parts by mass) of base used] + [amount (parts by mass) of compound (8)] + [amount (parts by mass) of solvent used] + [amount (parts by mass) of other components used]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When this ratio is equal to or greater than the lower limit, the depolymerization of compound (4) proceeds more easily.

[0352] On the other hand, the proportion is 100% by mass or less.

[0353] When the optional component (i.e., the solvent or the other component) is not used when depolymerizing the compound (4), the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0354] <Other Conditions> In the depolymerization step of the depolymerization method (iv), compound (4), a base, compound (8), and, if necessary, a solvent and, if necessary, the other components are mixed, and the resulting mixture is heated and stirred, thereby enabling depolymerization of compound (4).

[0355] In the depolymerization step of the depolymerization method (iv), the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (4) are the same as the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (1), respectively, in the depolymerization step of the depolymerization method (i).

[0356] In the depolymerization method (iv), after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (i), to isolate the target substance (product), and the isolated target substance may be further purified, if necessary. Alternatively, after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (i), and then used for the next intended application without isolating the target substance.

[0357] The structure of the product obtained by the depolymerization method (iv) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0358] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited to the examples shown below.

[0359] <<Depolymerization of Polysulfone (Depolymerization Method (i))>>

[0360] Example 1 Under an argon atmosphere, a colorless, transparent pellet-shaped polysulfone (44.7 mg; the amount corresponding to 0.101 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was dissolved in a 0.8 M solution of phosphazene base P４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (also known as 2-ethylhexanethiol, corresponding to compound (8)) (36.5 mg, 0.250 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0361] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard. A small amount of the resulting mixture was taken as a sample and analyzed with deuterated chloroform (CDCl ３ ) and dissolve it in １ The resultant was analyzed by H NMR. As a result, it was confirmed that the target products (depolymerization products), bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)), were obtained quantitatively (in a yield of more than 95%).

[0362] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0363] The crude product obtained was subjected to silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) to obtain the target compounds, bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS) (yield 45.3 mg, 89%) and bisphenol A (BPA) (yield 21.3 mg, 94%).

[0364] The NMR analysis results of the obtained bis(4-(2-ethylhexylthio)phenyl)sulfone and bisphenol A are shown below.

[0365] Bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS): 1 H NMR (600 MHz, CDCl3) δ 0.87-0.90 (m, 12H, methyl), 1.24-1.31 (m, 8H, methylene), 1.36-1.49 (m, 8H, methylene), 1.61 (sept, J = 6.3 Hz, 2H, methyne), 2.92 (d, J = 6.4 Hz, 4H, SCH2), 7.30 (AA'BB', 4H, aromatic), 7.77 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, CDCl) δ 10.7, 14.1, 22.9, 25.7, 28.7, 32.4, 36.3, 38.6, 126.7, 127.7, 137.6, 146.2. Bisphenol A (BPA): 1 H NMR (600 MHz, acetone-d6) δ 1.58 (s, 6H, methyl), 6.72 (AA'BB', 4H, aromatic), 7.05 (AA'BB', 4H, aromatic), 8.07 (s, 2H, OH).

[0366] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0367] [Example 2] Under an argon atmosphere, a colorless and transparent pellet-shaped polysulfone (45.3 mg; the amount corresponding to 0.102 mmol of the repeating unit in the general formula (1); weight average molecular weight: 60,000; manufactured by Nacalai Tesque, Inc., Cat. No. 178910050) was dissolved in a phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (36.5 mg, 0.250 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0368] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated chloroform. １ The resultant was analyzed by H NMR. As a result, it was confirmed that the target products (depolymerization products), bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)), were obtained quantitatively (in a yield of more than 95%).

[0369] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0370] From the obtained crude product, silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30) was performed to obtain the target products, bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS) (yield 51 mg, 99%) and bisphenol A (BPA) (yield 25.3 mg, over 99%). １ H NMR and １３ Analysis by C NMR gave results similar to those in Example 1.

[0371] (In the formula, n １０２is an integer (preferably 10 to 200).) As is clear from the results of Examples 1 and 2, even when polysulfones having different degrees of polymerization were used, depolymerization proceeded well, and the target products, bis(4-(2-ethylhexylthio)phenyl)sulfone and bisphenol A, were obtained in high yields.

[0372] During the depolymerization process, the carbon-sulfur bonds in the diphenyl sulfone moieties in the polysulfone were hardly cleaved, confirming that the carbon-oxygen bonds, which have stronger bonding strength than ordinary carbon-sulfur bonds, were selectively cleaved.

[0373] <<Depolymerization of Polysulfone (Conventional Method)>>

[0374] Comparative Example 1 In accordance with the method described in Non-Patent Document 6, depolymerization of polysulfone was carried out by a conventional method.

[0375] That is, under an argon atmosphere, a colorless, transparent pellet-shaped polysulfone (43.8 mg; the amount corresponding to 0.099 mmol of the repeating unit in the general formula (1); weight average molecular weight: 35,000; number average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was dissolved in sodium tert-butoxide (28.8 mg, 0.3 mmol; a three-fold molar amount (3 equivalents) relative to the repeating unit in the general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and phenethyl mercaptan (C ６ H ５ CH ２ CH ２ Then, 55.6 mg of (SH) (corresponding to compound (8)) (0.4 mmol, a 4-fold molar amount (4 equivalents) relative to the repeating unit in general formula (1)) was added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0376] The temperature of the resulting reaction mixture was then returned to room temperature, and 41.4 mg (0.3 mmol) of methyl iodide was added, followed by stirring at 100° C. for 1 hour. Ethyl acetate (1.5 mL) was added to the resulting reaction mixture, and the organic layer was washed successively with water and a saturated aqueous sodium chloride solution. The resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0377] Next, 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added to the crude product as an internal standard, and a small amount of the resulting product was taken as a sample and analyzed by deuterated acetone ((CD ３ ) ２ CO), １ H NMR and １３ The resulting mixture was analyzed by C NMR. As a result, it was confirmed that the target products (depolymerization products) were bis(4-methylthiophenyl)sulfone (BMTPS, corresponding to compound (18)) (yield 84%) and bisphenol A (yield 80%). The yields of these target products were lower than those in Examples 1 and 2.

[0378] The analysis results are shown below.

[0379] Bis(4-methylthiophenyl)sulfone (BMTPS): 1 H NMR (600 MHz, acetone-d6) δ 2.48 (s, 6H, SCH3), 7.27 (AA'BB', 4H, aromatic), 7.79 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, acetone-d6) δ 14.8, 125.5, 127.8, 137.5, 146.5.

[0380] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0381] <<Depolymerization of Polyether Ether Sulfone (Depolymerization Method (i))>>

[0382] Example 3 Under an argon atmosphere, brown pellet-shaped polyether ether sulfone (34.1 mg; the amount corresponding to 0.105 mmol of the repeating unit in the general formula (1); manufactured by Sigma-Aldrich, Cat. No. 440965) was dissolved in 0.8 M phosphazene base P ４ 13.2 μL of n-hexane solution of phosphazene base P ４0.0105 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)), and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (corresponding to compound (8)) (38.7 mg, 0.263 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polyether ether sulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0383] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated chloroform. １ The product was analyzed by H NMR. As a result, it was confirmed that the target products (depolymerization products), bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS, corresponding to compound (18)) and hydroquinone (HQ, corresponding to compound (122)), were obtained quantitatively (in a yield of more than 95%).

[0384] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0385] The crude product obtained was subjected to silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) to obtain the target compounds, bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS) (yield 57.6 mg, over 99%) and hydroquinone (HQ) (yield 9.3 mg, 80%).

[0386] The obtained bis(4-(2-ethylhexylthio)phenyl)sulfone １ H NMR and １３ The results of the C NMR analysis were the same as in Example 1.

[0387] The resulting hydroquinone １The results of the H NMR analysis are shown below.

[0388] Hydroquinone (HQ): 1 H NMR (600 MHz, acetone-d6) δ 6.66 (s, 4H).

[0389] (In the formula, n １０３ is an integer (preferably 10 to 200).

[0390] <<Depolymerization of Polyphenylsulfone (Depolymerization Method (i))>>

[0391] Example 4 Sheet-like polyphenylsulfone (manufactured by Standard-Testpiece, Cat. No. RMOLDED0050) was processed into powder.

[0392] Under an argon atmosphere, the colorless powdery polyphenylsulfone obtained above (40.1 mg; the amount corresponding to 0.1 mmol of the repeating unit in the general formula (1)) was diluted with 0.8 M of phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.3 mg, 0.006 mmol, 6 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (corresponding to compound (8)) (36.7 mg, 0.251 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polyphenylsulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0393] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated chloroform. １The resulting product was analyzed by H NMR. As a result, it was confirmed that the target products (depolymerization products), bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS, corresponding to compound (18)) and 4,4′-dihydroxybiphenyl (4,4′-DHBP, corresponding to compound (123)), were obtained quantitatively (in a yield of more than 95%).

[0394] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0395] The crude product was purified by silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) to obtain the target compounds, bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS) (yield 49 mg, 95%) and 4,4′-dihydroxybiphenyl (4,4′-DHBP) (yield 19 mg, over 99%).

[0396] The obtained bis(4-(2-ethylhexylthio)phenyl)sulfone １ H NMR and １３ The results of the C NMR analysis were the same as in Example 1.

[0397] The obtained 4,4'-dihydroxybiphenyl １ The results of the H NMR analysis are shown below.

[0398] 4,4'-Dihydroxybiphenyl (4,4'-DHBP): 1 H NMR (600 MHz, acetone-d6) δ 6.87 (AA'BB', 4H, aromatic), 7.40 (AA'BB', 4H, aromatic), 8.32 (s, 2H, OH).

[0399] (In the formula, n １０４ is an integer (preferably 10 to 200).

[0400] <<Depolymerization of Polyethersulfone (Depolymerization Method (iv))>>

[0401] Example 5 Under an argon atmosphere, yellow, transparent pellet-shaped polyethersulfone (23.2 mg; the amount corresponding to 0.1 mmol of the repeating unit in the general formula (4); manufactured by Sigma-Aldrich, Cat. No. 191094) was dissolved in 0.8 M phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (4)) and tripotassium phosphate (K ３ P.O. ４ ) (1.2 mg, 0.0057 mmol, 6 mol % relative to the repeating unit in general formula (4)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (corresponding to compound (8)) (22.1 mg, 0.151 mmol, 1.5 times the molar amount (1.5 equivalents) relative to the repeating unit in general formula (4)) were added sequentially to dissolve the polyethersulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0402] The resulting yellow reaction mixture was then allowed to return to room temperature, and the crude product was obtained by evaporation under reduced pressure.

[0403] From the obtained crude product, silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) was performed to obtain the target substances, bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS) (yield 10.9 mg, yield 22%), 4-(2-ethylhexylthio)-4'-hydroxydiphenylsulfone (compound (a)) (yield 7.8 mg, yield 21%), bisphenol S (BPS) (yield 3.3 mg, yield 13%), and 4-((4-(4-((4-((2-ethylhexyl)thio)phenyl)-sulfoyl)phenoxy)phenyl)sulfonyl)phenol (compound (b)) (yield 4.7 mg, yield 15%).

[0404] The obtained bis(4-(2-ethylhexylthio)phenyl)sulfone １ H NMR and １３The results of the C NMR analysis were the same as in Example 1.

[0405] The NMR analysis results of the other compounds obtained above are shown below.

[0406] Compound (a): 1 H NMR (600 MHz, CDCl3) δ 0.88 (t, J = 7.0 Hz, 3H, methyl), 0.89 (t, J = 7.5 Hz, 3H, methyl), 1.25-1.29 (m, 4H, methylene), 1.37-1.48 (m, 4H, methylene), 1.61 (sept, J = 6.3 Hz, 1H, methyne), 2.92 (d, J = 6.2 Hz, 4H, SCH2), 6.89 (AA'BB', 2H, aromatic), 7.30 (AA'BB', 2H, aromatic), 7.76 (AA'BB', 2H, aromatic), 7.80 (AA'BB', 2H, aromatic). 13 C NMR (151 MHz, CDCl) δ 10.7, 14.1, 22.9, 25.7, 28.7, 32.4, 36.3, 38.6, 116.0, 126.7, 127.6, 130.0, 133.6, 137.9, 146.0, 159.8. Bisphenol S (BPS): 1 H NMR (600 MHz, acetone-d6) δ 6.97 (AA'BB', 4H, aromatic), 7.77 (AA'BB', 4H, aromatic), 9.44 (br, 2H, OH). Compound (b): 1H NMR (600 MHz, acetone-d6) δ 0.87 (t, J = 7.1 Hz, 3H, methyl), 0.91 (t, J = 7.5 Hz, 3H, methyl), 1.27-1.33 (m, 4H, methylene), 1.40-1.51 (m, 4H, methylene), 1.65 (sept, J = 6.2 Hz, 1H, methyne), 3.07 (d, J = 6.3 Hz, 4H, SCH2), 7.01 (AA'BB', 2H, aromatic), 7.238 (AA'BB', 2H, aromatic), 7.242 (AA'BB', 2H, aromatic), 7.49 (AA'BB', 2H, aromatic), 7.83 (AA'BB', 2H, aromatic), 7.86 (AA'BB', 2H, aromatic), 7.98 (AA'BB', 2H, aromatic), 8.00 (AA'BB', 2H, aromatic), 9.59 (br, 1H, OH). 13 C NMR (151 MHz, acetone-d6) δ 11.0, 14.3, 23.6, 26.3, 29.4, 33.1, 36.5, 39.4, 117.0, 120.5, 120.6, 127.7, 128.8, 130.7, 130.9, 131.0, 133.4, 138.6, 138.9, 139.7, 147.1, 160.3, 160.9, 162.8.

[0407] (In the formula, n ４０１ is an integer (preferably 10 to 200).

[0408] <<Depolymerization of Polyetherimide (Depolymerization Method (iii))>>

[0409] Example 6 Under an argon atmosphere, yellow transparent pellet-shaped polyetherimide (59.2 mg; the amount corresponding to 0.1 mmol of the repeating unit in the general formula (3); manufactured by Sigma-Aldrich, Cat. No. 700193) was dissolved in 0.8 M phosphazene base P ４13.2 μL of n-hexane solution of phosphazene base P ４ 0.0105 mmol of -t-Bu (11 mol % relative to the repeating unit in the general formula (3)), and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating unit in general formula (3)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (38.7 mg, 0.263 mmol, 2.6 times the molar amount (2.6 equivalents) relative to the repeating unit in general formula (3)) were added sequentially to dissolve the polyetherimide, and the resulting mixture was stirred at 150°C for 16 hours.

[0410] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated chloroform. １ The result was analyzed by H NMR, and it was confirmed that the target product (depolymerization product), compound (c) (corresponding to compound (38)), and bisphenol A (BPA, corresponding to compound (31)), were obtained quantitatively (in a yield of more than 95%).

[0411] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0412] From the obtained crude product, silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30) was performed to obtain the target compound (c) (yield 49.2 mg, 75%) and bisphenol A (BPA) (yield 24.9 mg, over 99%). １ The results of the H NMR analysis were the same as in Example 1.

[0413] Compound (c) １ H NMR and １３ The results of the C NMR analysis are shown below.

[0414] Compound (c): 1 H NMR (600 MHz, CDCl3) δ 0.90-0.95 (m, 12H, methyl), 1.30-1.34 (m, 8H, methylene), 1.43-1.53 ​​(m, 8H, methylene), 1.68 (sept, J = 6.4 Hz, 2H, methyne), 3.04 (d, J = 6.4 Hz, 4H, SCH2), 7.52 (dd, J = 2.0, 8.0 Hz, 2H, aromatic), 7.59 (dd, J = 1.7, 7.9 Hz, 2H, aromatic), 7.62-7.63 (m, 1H, aromatic), 7.67 (t, J = 2.0 Hz, 1H, aromatic), 7.76 (d, J = 1.3 Hz, 2H, aromatic), 7.79 (dd, J = 0.26, 7.9 Hz, 2H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 10.8, 14.1, 22.9, 25.7, 28.8, 32.5, 36.7, 38.6, 120.7, 123.78, 123.85, 125.4, 127.2, 129.4, 131.8, 132.4 (two signals), 148.7, 166.6, 166.7.

[0415] (In the formula, n ３０１ is an integer (preferably 10 to 200).

[0416] <<Depolymerization of polyether ether ketone (depolymerization method (ii))>>

[0417] Example 7 Under an argon atmosphere, powdered polyether ether ketone (28.8 mg; the amount corresponding to 0.1 mmol of the repeating unit in the general formula (2); weight-average molecular weight: 20,800; number-average molecular weight: 10,300; manufactured by Sigma-Aldrich, Cat. No. 456640) was dissolved in potassium tert-butoxide (KOt-Bu) (1.1 mg, 0.01 mmol; manufactured by Sigma-Aldrich, Cat. No. 456640). No. 156671-25G (10 mol % relative to the repeating units in general formula (2)), 1,3-dimethyl-2-imidazolidinone (DMI) (0.2 mL), and 2-ethylhexyl mercaptan (31 mg, 0.2 mmol, twice the molar amount (2 equivalents) relative to the repeating units in general formula (2)) were added sequentially to dissolve the polyether ether ketone, and then the resulting mixture was stirred at 150°C for 16 hours.

[0418] Next, the temperature of the obtained reaction mixture was returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the obtained mixture was taken as a sample and dissolved in deuterated chloroform. １ The product was analyzed by H NMR. The yields of the target product (depolymerization product), bis(4-(2-ethylhexylthio)phenyl)methanone (BEHTPM, corresponding to compound (28)), hydroquinone (HQ, corresponding to compound (22)), and the intermediate compound (d) were calculated. The results are shown in Table 1.

[0419] The resulting hydroquinone １ The results of the H NMR analysis were the same as in Example 3.

[0420] The NMR analysis results of BEHTPM and compound (d) are shown below.

[0421] BEHTPM: 1H NMR (600 MHz, CDCl3) δ 0.89-0.93 (m, 12H, methyl), 1.29-1.31 (m, 8H, methylene), 1.39-1.53 ​​(m, 8H, methylene), 1.64 (sept, J = 6.2 Hz, 2H, methyne), 2.98 (d, J = 6.4 Hz, 4H, SCH2), 7.30 (d, 8.4 Hz, 4H, aromatic), 7.69 (d, J = 8.4 Hz, 4H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 10.8, 14.1, 23.0, 25.7, 28.8, 32.5, 36.5, 38.7, 126.3, 130.4, 134.1, 144.6, 195.0. Compound (d): 1 H NMR (600 MHz, CDCl3) δ 0.89 (t, J = 7.0 Hz, 3H, methyl), 0.91 (t, J = 7.5 Hz, 3H, methyl), 1.30-1.51 (m, 8H, methyl), 1.64 (sept, J = 6.2 Hz, 1H, methyne), 2.97 (d, J = 6.4 Hz, 2H, SCH2), 4.80 (s, 1H, OH), 6.87 (AA'BB', 2H, aromatic), 6.97 (AA'BB', 2H, aromatic), 6.99 (AA'BB', 2H, aromatic), 7.32 (AA'BB', 2H, aromatic), 7.69 (AA'BB', 2H, aromatic), 7.76 (AA'BB', 2H, aromatic). In Table 1, "base (amount used (mol %))" means the ratio of the amount of base used (number of moles) to the amount of repeating units (number of moles) in general formula (2), as described above.

[0422] [Examples 8 to 13] Depolymerization of polyether ether ketone was carried out in the same manner as in Example 7, except that a base shown in Table 1 (0.01 mmol, 10 mol% relative to the repeating unit in general formula (2)) was used instead of potassium tert-butoxide (0.01 mmol). That is, the base used was potassium hydroxide (KOH) in Example 8, tripotassium phosphate (K ３ P.O. ４ In Example 10, cesium carbonate (Cs ２ CO ３ ), and in Example 11, the phosphazene base P ４ -t-Bu, and in Example 12, the phosphazene base P ２ -t-Bu, and in Example 13, the phosphazene base P ２ The results are shown in Table 1.

[0423] In Table 1, "Phosphazene base P ４ -t-Bu" (Example 11), "Phosphazene base P ２ -t-Bu" (Example 12) and "Phosphazene base P ２ -Et" (Example 13) were respectively ４ -t-Bu", "P ２ -t-Bu" and "P ２ -Et".

[0424] [Example 14] Phosphazene base P ４ Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that the amount of -t-Bu used was changed from 0.01 mmol (10 mol % relative to the repeating units in general formula (2)) to 0.005 mmol (5 mol % relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0425] Example 15 Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that the amount of 2-ethylhexyl mercaptan used was changed from 0.2 mmol (twice the molar amount (2 equivalents) relative to the repeating units in general formula (2)) to 0.25 mmol (2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0426] [Example 16] Phosphazene base P ４ -t-Bu (0.01 mmol, 10 mol% relative to the repeating unit in the general formula (2)) and further tripotassium phosphate (K ３ P.O. ４ Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that N,N-dimethylacetamide (DMAc) (0.2 mL) was used instead of 1,3-dimethyl-2-imidazolidinone (0.2 mL), and the amount of 2-ethylhexyl mercaptan was changed from 0.2 mmol (2 times the molar amount (2 equivalents) relative to the repeating units in general formula (2)) to 0.25 mmol (2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0427] Example 17 Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that the reaction temperature during depolymerization was changed from 150°C to 120°C, and the amount of 2-ethylhexyl mercaptan used was changed from 0.2 mmol (twice the molar amount (2 equivalents) relative to the repeating units in general formula (2)) to 0.25 mmol (2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0428] Example 18 Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that the reaction temperature during depolymerization was changed from 150°C to 100°C, and the amount of 2-ethylhexyl mercaptan used was changed from 0.2 mmol (twice the molar amount (2 equivalents) relative to the repeating units in general formula (2)) to 0.25 mmol (2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0429] Example 19: Benzonitrile (C ６ H ５Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that 0.2 mL of 2-ethylhexyl mercaptan (CN) was used, and the amount of 2-ethylhexyl mercaptan used was 0.25 mmol (2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (2)) instead of 0.2 mmol (2 times the molar amount (2 equivalents) relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0430] [Example 20] Instead of 1,3-dimethyl-2-imidazolidinone (0.2 mL), xylene (C ６ H ４ (CH ３ ) ２ Depolymerization of polyether ether ketone was carried out in the same manner as in Example 11, except that 0.2 mL of 2-ethylhexyl mercaptan was used, and that the amount of 2-ethylhexyl mercaptan used was 0.25 mmol (2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (2)) instead of 0.2 mmol (2 times the molar amount (2 equivalents) relative to the repeating units in general formula (2)). The results are shown in Table 1.

[0431] In Examples 8 to 20, the NMR analysis results of the obtained BEHTPM, hydroquinone, and compound (d) were the same as in Example 7.

[0432] (In the formula, n ２０１ is an integer (preferably 10 to 200).

[0433] As is clear from the above results, it was confirmed that BEHTPM and hydroquinone can be obtained in good yields even when the type of base is changed, for example, whether the base is an organic base or an inorganic base.

[0434] Among them, the phosphazene base P ４ -t-Bu (Examples 11, 14 to 16), phosphazene base P ２ The yields of BEHTPM and hydroquinone were higher when phosphazene base P-t-Bu (Example 12), cesium carbonate (Example 10), or potassium tert-butoxide (Example 7) was used as the base. ４The combined use of -t-Bu and tripotassium phosphate (Example 16) gave particularly high yields of BEHTPM and hydroquinone.

[0435] A comparison of Examples 15, 17, and 18 confirmed that the higher the reaction temperature during depolymerization (for example, 140 to 180° C.), the higher the yield of BEHTPM and hydroquinone.

[0436] A comparison of Examples 11 and 14 confirmed that the yield of BEHTPM and hydroquinone tended to increase when a larger amount of base was used (for example, 0.1 to 0.3 equivalents).

[0437] A comparison of Examples 11 and 15 confirmed that the yield of BEHTPM and hydroquinone tended to increase when a larger amount of compound (8) was used (for example, 2.2 to 4 equivalents, preferably 2.2 to 4 equivalents).

[0438] A comparison of Examples 17, 19 and 20 confirmed that the use of 1,3-dimethyl-2-imidazolidinone as a solvent increased the yield of BEHTPM and hydroquinone.

[0439] <<Depolymerization of Polyether Ether Ketone (Depolymerization Method (ii))>> [Example 21] In the same manner as in Example 16, depolymerization of polyether ether ketone was carried out.

[0440] That is, under an argon atmosphere, powdered polyether ether ketone (28.8 mg; the amount corresponding to 0.1 mmol of the repeating unit in the general formula (2); weight average molecular weight: 20,800; number average molecular weight: 10,300; manufactured by Sigma-Aldrich, Cat. No. 456640) was dissolved in 0.8 M of phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (2)) and tripotassium phosphate (K ３ P.O. ４Compound (8) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating unit in general formula (2)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-ethylhexyl mercaptan (corresponding to compound (8)) (31 mg, 0.2 mmol, 2-fold molar amount (2 equivalents) relative to the repeating unit in general formula (2)) were added sequentially to dissolve the polyether ether ketone, and the resulting mixture was stirred at 150° C. for 16 hours.

[0441] The resulting yellow reaction mixture was then allowed to return to room temperature, and the crude product was obtained by evaporation under reduced pressure.

[0442] The crude product was purified by silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) to obtain the target compounds, bis(4-(2-ethylhexylthio)phenyl)methanone (BEHTPM) (yield 39.9 mg, 85%) and hydroquinone (HQ) (yield 6.6 mg, 61%).

[0443] The NMR analysis results of the resulting BEHTPM and hydroquinone were the same as those in Example 7.

[0444] (In the formula, n ２０１ is an integer (preferably 10 to 200).

[0445] <<Depolymerization of carbon fiber reinforced polyetheretherketone (depolymerization method (ii))>>

[0446] Example 22 Carbon fiber-reinforced polyether ether ketone (TECAPEEK CF30, Cat. No. 3-3094-02, manufactured by Ensinger) was prepared. In this carbon fiber-reinforced polyether ether ketone, the proportion of the polyether ether ketone content relative to the total mass of the carbon fiber-reinforced polyether ether ketone was 70 mass%.

[0447] This carbon fiber reinforced polyetheretherketone was processed into powder form.

[0448] The polyether ether ketone was depolymerized and the target product was isolated in the same manner as in Example 21, except that the powder of carbon fiber-reinforced polyether ether ketone (in an amount corresponding to 0.1 mmol of the repeating unit in general formula (2)) obtained above was used instead of powdered polyether ether ketone (in an amount corresponding to 0.1 mmol of the repeating unit in general formula (2)). As a result, the target products, bis(4-(2-ethylhexylthio)phenyl)methanone (BEHTPM) (yield 86%) and hydroquinone (HQ) (yield 70%) were obtained.

[0449] The NMR analysis results of the resulting BEHTPM and hydroquinone were the same as those in Example 7.

[0450] <<Depolymerization of Glass Fiber-Reinforced Polyether Ether Ketone (Depolymerization Method (ii))>> [Example 23] Glass fiber-reinforced polyether ether ketone (TECAPEEK GF30, Cat. No. 3-3095-01, manufactured by Ensinger) was prepared. In this glass fiber-reinforced polyether ether ketone, the proportion of the polyether ether ketone content relative to the total mass of the glass fiber-reinforced polyether ether ketone was 30 mass%.

[0451] This glass fiber reinforced polyetheretherketone was processed into a powder form.

[0452] The polyether ether ketone was depolymerized and the target product was isolated in the same manner as in Example 21, except that the powder of glass fiber-reinforced polyether ether ketone (in an amount corresponding to 0.1 mmol of the repeating unit in general formula (2)) obtained above was used instead of the powdery polyether ether ketone (in an amount corresponding to 0.1 mmol of the repeating unit in general formula (2)). As a result, the target products, bis(4-(2-ethylhexylthio)phenyl)methanone (BEHTPM) (yield 76%) and hydroquinone (HQ) (yield 33%), were obtained.

[0453] The NMR analysis results of the resulting BEHTPM and hydroquinone were the same as those in Example 7.

[0454] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 24] Under an argon atmosphere, a colorless, transparent pellet-like polysulfone (44.6 mg; an amount corresponding to 0.100 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich Corporation, Cat. No. 428302) was depolymerized with 0.8 M of phosphazene base P ４ 12.6 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-phenylethyl mercaptan (also known as 2-phenylethanethiol, corresponding to compound (8)) (35.0 mg, 0.253 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 100°C for 64 hours.

[0455] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated acetone. １ The resulting product was analyzed by H NMR. As a result, it was confirmed that the target products (depolymerization products) of bis(4-(2-phenylethylthio)phenyl)sulfone (BPETPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)) were obtained.

[0456] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0457] From the obtained crude product, silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30) was performed to obtain the target products, bis(4-(2-phenylethylthio)phenyl)sulfone (BPETPS) (yield 46.9 mg, 95%) and bisphenol A (BPA) (yield 24.7 mg, 95%). １ H NMR and １３ The results of the C NMR analysis are shown below. Bisphenol A is １ Analysis by 1 H NMR gave results similar to those in Example 1.

[0458] BPETPS: 1 H NMR (600 MHz, CDCl3) δ 2.96 (t, J = 7.9 Hz, 4H, methyne), 3.22 (d, J = 7.9 Hz, 4H, SCH2), 7.20 (d, J = 7.0 Hz, 4H, aromatic), 7.22-7.24 (m, 2H, aromatic), 7.30-7.33 (m, 8H, aromatic), 7.79 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 33.5, 35.0, 1268, 126.9, 127.9, 128.5, 128.7, 138.0, 139.4, 145.0.

[0459] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0460] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 25] Under an argon atmosphere, a colorless, transparent pellet-like polysulfone (44.3 mg; an amount corresponding to 0.10 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich Corporation, Cat. No. 428302) was depolymerized with 0.8 M of phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 2-mercaptoethanol (corresponding to compound (8)) (19.6 mg, 0.25 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 100°C for 64 hours.

[0461] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated acetone. １ The resulting product was analyzed by H NMR, and it was confirmed that the target products (depolymerization products) were bis(4-(2-hydroxyethylthio)phenyl)sulfone (BHETPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)).

[0462] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0463] The crude product was subjected to silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30) to obtain the target compounds, bis(4-(2-hydroxyethylthio)phenyl)sulfone (BHETPS) (yield: 29.1 mg, 79%) and bisphenol A (BPA) (yield: 17.0 mg, 71%). １ H NMR and １３ The results of the C NMR analysis are shown below. Bisphenol A is １ Analysis by 1 H NMR gave results similar to those in Example 1.

[0464] BHETPS: 1H NMR (600 MHz, CDCl3) δ 3.21 (t, J = 6.6 Hz, 4H, SCH2), 3.76-3.78 (m, 4H, HOCH2), 4.12 (br, 2H, OH), 7.50 (AA'BB', 4H, aromatic), 7.84 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 35.0, 61.1, 127.7, 128.7, 139.2, 146.3.

[0465] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0466] <<Depolymerization of Polysulfone (Depolymerization Method (i))>>

[0467] Example 26 Under an argon atmosphere, a colorless, transparent pellet-shaped polysulfone (44.5 mg; the amount corresponding to 0.101 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was dissolved in a 0.8 M solution of phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.3 mg, 0.006 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 3-(triethoxysilyl)propanethiol (corresponding to compound (8)) (59.4 mg, 0.25 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0468] The temperature of the resulting orange reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated acetone. １ The product was analyzed by H NMR, and as a result, it was confirmed that the target products (depolymerization products), bis(4-(3-(triethoxysilyl)propylthio)phenyl)sulfone (BTEOSPTPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)), were obtained.

[0469] The above １ The sample used for H NMR analysis was added back to the orange reaction mixture, and the crude product was obtained by evaporation under reduced pressure.

[0470] From the obtained crude product, silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30) was performed to obtain the target products, bis(4-(3-(triethoxysilyl)propylthio)phenyl)sulfone (BTEOSPTPS) (yield 18.5 mg, 26%) and bisphenol A (BPA) (yield 24.9 mg, slightly more than 99%). １ H NMR and １３ The results of the C NMR analysis are shown below. Bisphenol A is １ Analysis by 1 H NMR gave results similar to those in Example 1.

[0471] BPETPS: 1 H NMR (600 MHz, CDCl3) δ 0.75-80 (m, 4H, methylene), 1.19 (t, J = 7.0 Hz, 18H, methyl), 1.79 (tt, J = 7.7 Hz, 4H, methylene), 2.99 (t, J = 7.5 Hz, 4H, SCH2), 3.79 (q, J = 7.0 Hz, 4H, OCH2), 7.30 (AA'BB', 4H, aromatic), 7.76 (AA'BB', 4H, aromatic). 13C NMR (151 MHz, CDCl3) δ 9.93, 18.3, 22.4, 34.6, 58.5, 126.7, 127.8, 137.7, 145.5.

[0472] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0473] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 27] Under an argon atmosphere, a colorless, transparent pellet-like polysulfone (44.1 mg; an amount corresponding to 0.100 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich Corporation, Cat. No. 428302) was depolymerized with 0.8 M of phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and cyclopentanethiol (corresponding to compound (8)) (25.4 mg, 0.25 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0474] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated acetone. １ The resulting product was analyzed by H NMR, and it was confirmed that the target products (depolymerization products) were bis(4-(cyclopentylthio)phenyl)sulfone (BcyPenTPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)).

[0475] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0476] From the obtained crude product, silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30) was performed to obtain the target products, bis(4-(cyclopentylthio)phenyl)sulfone (BcyPenTPS) (yield 39.3 mg, 94%) and bisphenol A (BPA) (yield 26.3 mg, slightly more than 99%). １ H NMR and １３ The results of the C NMR analysis are shown below. Bisphenol A is １ Analysis by 1 H NMR gave results similar to those in Example 1.

[0477] BPETPS: 1 H NMR (600 MHz, CDCl3) δ 1.59-1.67 (m, 8H, methylene), 1.75-1.81 (m, 4H, methylene), 2.09-2.16 (m, 4H, methylene), 3.65-3.70 (m, 2H, SCH), 7.32 (AA'BB', 4H, aromatic), 7.77 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 24.9, 33.4, 44.1, 127.2, 127.7, 137.6, 146.2.

[0478] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0479] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 28] Under an argon atmosphere, a colorless, transparent pellet-like polysulfone (44.1 mg; an amount corresponding to 0.100 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was depolymerized with 0.8 M of phosphazene base P４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ ) (1.1 mg, 0.005 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and trimethylsilylmethylthiol (corresponding to compound (8)) (30.2 mg, 0.25 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 64 hours.

[0480] Next, the temperature of the obtained brown reaction mixture was returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the obtained mixture was taken as a sample and dissolved in deuterated acetone. １ The resulting product was analyzed by H NMR, and it was confirmed that the depolymerization products, bis(4-methylthiophenyl)sulfone (BMTPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)), were obtained.

[0481] The above １ The sample used for H NMR analysis was added back to the brown reaction mixture and evaporated under reduced pressure to give the crude product.

[0482] From the obtained crude product, bis(4-methylthiophenyl)sulfone (BMTPS) (yield 23.0 mg, 74%) and bisphenol A (BPA) (yield 23.3 mg, slightly more than 99%) were obtained by silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4 → 70 / 30). １ H NMR and bisphenol A １ When H NMR was performed, the same results as in Comparative Example 1 were obtained.

[0483] (In the formula, n１０１ is an integer (preferably 10 to 200).

[0484] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 29] Under an argon atmosphere, sodium tert-butoxide (2.0 mg, 0.02 mmol, 20 mol % relative to the repeating units in the general formula (1)), N,N-dimethylacetamide (DMAc) (0.2 mL), and 4-tert-butylphenyl mercaptan (also known as 4-tert-butylbenzenethiol) (41.4 mg, 0.25 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in the general formula (1)) were sequentially added to colorless, transparent pellet-shaped polysulfone (44.3 mg; an amount corresponding to 0.100 mmol of the repeating units in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 16 hours.

[0485] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated acetone. １ The product was analyzed by H NMR, and as a result, it was confirmed that the target products (depolymerization products), bis(4-(4-tert-butylphenylthio)phenyl)sulfone (BBPTPS, corresponding to compound (18)) and bisphenol A (BPA, corresponding to compound (121)), were obtained.

[0486] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0487] The crude product thus obtained was subjected to silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) to obtain the target compounds, bis(4-(4-tert-butylphenylthio)phenyl)sulfone (BBPTPS) (yield 53.8 mg, 98%) and bisphenol A (BPA) (yield 23.2 mg, over 99%).

[0488] The obtained BBPTPS １ H NMR and １３ The results of the C NMR analysis are shown below. Bisphenol A is １ Analysis by 1 H NMR gave results similar to those in Example 1.

[0489] BBP TPS: 1 H NMR (600 MHz, CDCl3) δ 1.34 (s, 18H, tBu), 7.19 (AA'BB', 4H, aromatic), 7.42-7.46 (m, 8H, aromatic), 7.64 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 31.3, 34.8, 126.7, 126.8, 128.1, 130.6, 134.0, 134.5, 144.9, 152.4, 194.9.

[0490] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0491] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 30] Under an argon atmosphere, powdery polyether ether ketone (29.0 mg; the amount corresponding to 0.1 mmol of the repeating unit in the general formula (2); weight average molecular weight: 20,800; number average molecular weight: 10,300; manufactured by Sigma-Aldrich, Cat. No. 456640) was depolymerized with 0.8 M of phosphazene base P ４ 12.5 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and cesium carbonate (Cs ３ CO ３) (4.3 mg, 0.01 mmol, 10 mol % relative to the repeating units in general formula (1)), 1,3-dimethyl-2-imidazolidinone (DMI) (1.0 mL), and 4-tert-butylphenyl mercaptan (also known as 4-tert-butylbenzenethiol) (corresponding to compound (8)) (40.5 mg, 0.24 mmol, 2.4 times the molar amount (2.4 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polysulfone, and the resulting mixture was stirred at 150°C for 109 hours.

[0492] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated acetone. １ The product was analyzed by H NMR, and it was confirmed that the depolymerization products, bis(4-(4-tert-butylphenylthio)phenyl)ketone (BBPTPK, corresponding to compound (18)) and hydroquinone (HQ, corresponding to compound (121), yield 75%), were obtained.

[0493] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0494] From the obtained crude product, bis(4-(4-tert-butylphenylthio)phenyl)ketone (BBPTPK) (yield: 44.1 mg, 86%) was obtained by silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30).

[0495] The obtained BBPTPK １ H NMR and １３ The results of the C NMR analysis are shown below. １ H NMR gave results similar to those of Comparative Example 7. 1H NMR (600 MHz, CDCl3) δ 1.34 (s, 18H, tBu), 7.19 (AA'BB', 4H, aromatic), 7.42-7.46 (m, 8H, aromatic), 7.64 (AA'BB', 4H, aromatic). 13 C NMR (151 MHz, CDCl3) δ 31.3, 34.8, 126.7, 126.8, 128.1, 130.6, 134.0, 134.5, 144.9, 152.4, 194.9.

[0496] (In the formula, n ２０１ is an integer (preferably 10 to 200).

[0497] <<Depolymerization of Polysulfone (Depolymerization Method (i))>> [Example 31] A baby bottle made of polyphenylsulfone (PPSU) (manufactured by ChuChu Co.) was cut into 5 mm sides.

[0498] Under an argon atmosphere, the light yellow polyphenylsulfone pieces obtained above (81.4 mg; the amount corresponding to 0.2 mmol of the repeating unit in the general formula (1)) were diluted with 0.8 M of phosphazene base P ４ 25.0 μL of n-hexane solution of phosphazene base P ４ 0.01 mmol of -t-Bu (10 mol % relative to the repeating unit in the general formula (1)) and tripotassium phosphate (K ３ P.O. ４ Compound (8) (2.1 mg, 0.001 mmol, 5 mol % relative to the repeating units in general formula (1)), N,N-dimethylacetamide (DMAc) (0.4 mL), and 2-ethylhexyl mercaptan (corresponding to compound (8)) (72.5 mg, 0.50 mmol, 2.5 times the molar amount (2.5 equivalents) relative to the repeating units in general formula (1)) were added sequentially to dissolve the polyphenylsulfone, and the resulting mixture was stirred at 150° C. for 20 hours.

[0499] The temperature of the resulting yellow reaction mixture was then returned to room temperature, and 1,4-dioxane (5.2 mg, 5.0 μL, 0.059 mmol) was added as an internal standard substance. A small amount of the resulting mixture was taken as a sample and dissolved in deuterated chloroform. １ The product was analyzed by H NMR, and the results confirmed the production of the target products (depolymerization products), bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS, corresponding to compound (18)) and 4,4′-dihydroxybiphenyl (4,4′-DHBP, corresponding to compound (123)).

[0500] The above １ The sample used for H NMR analysis was added back to the yellow reaction mixture and evaporated under reduced pressure to give the crude product.

[0501] The crude product was purified by silica gel column chromatography (developing solvent: hexane / ethyl acetate 96 / 4→70 / 30) to obtain the target compounds, bis(4-(2-ethylhexylthio)phenyl)sulfone (BEHTPS) (yield 87 mg, 84%) and 4,4′-dihydroxybiphenyl (4,4′-DHBP) (yield 34 mg, 91%).

[0502] The obtained bis(4-(2-ethylhexylthio)phenyl)sulfone １ H NMR and １３ The results of the C NMR analysis were the same as in Example 1.

[0503] The obtained 4,4'-dihydroxybiphenyl １ The results of the H NMR analysis were the same as in Example 4.

[0504] (In the formula, n １０４ is an integer (preferably 10 to 200).

[0505] (Embodiment 2) Hereinafter, embodiment 2 of the present invention will be described, but even if the same terms as those in the above-mentioned embodiment are used, they may have different meanings. In addition, Examples 1 to 23 described below are different from the examples of embodiment 1 described above. ◎Method for depolymerizing a compound

[0506] <<Depolymerization Method (1)>> A method for depolymerizing (decomposing) a compound according to one embodiment of the present invention comprises decomposing a compound represented by the following general formula (1): (In the formula, n １ is an integer of 2 or more (preferably, 10 to 200); Z １１ and Z １２ are each independently a group other than a hydrogen atom; m １１ and m １２ are each independently an integer of 0 to 4, and m １１ When n is an integer of 1 or more, １ ×m １１ Z １１ may be the same or different, m １２ When n is an integer of 1 or more, １ ×m １２ Z １２ may be the same or different; Ar １ is represented by the following general formula (91), (92) or (93):

[0507] (In the formula, X １１ , X １２ , X ２１ , X ３１ and X ３２ are each independently a group other than a hydrogen atom; １１ , l １２ , l ２１ , l ３１ and l ３２ are each independently an integer of 0 to 4, １１ When n is an integer of 1 or more, １ ×l １１ X of pieces １１ may be the same or different, １２ When n is an integer of 1 or more, １ ×l １２ X of pieces １２ may be the same or different, ２１ When n is an integer of 1 or more, １ ×l ２１ X of pieces ２１ may be the same or different, ３１ When n is an integer of 1 or more, １ ×l ３１X of pieces ３１ may be the same or different, ３２ When n is an integer of 1 or more, １ ×l ３２ X of pieces ３２ may be the same or different.) and the bonds marked with * and ** in the general formulae (91), (92), and (93) are respectively formed with respect to the oxygen atom in the general formula (1).) is depolymerized in the presence of a hydroxide to give a compound (compound (1)) represented by the following general formula (11):

[0508] (In the formula, Z １１ , Z １２ , m １１ and m １２ are the same as above.) or a salt thereof (hereinafter, may be referred to as "compound (11)") and a compound represented by the following general formula (121), (122), or (123):

[0509] (In the formula, X １１ , X １２ , X ２１ , X ３１ , X ３２ , l １１ , l １２ , l ２１ , l ３１ and l ３２ are the same as above.) (herein, these may be referred to as “compound (121),” “compound (122),” and “compound (123),” respectively) or a salt thereof. Herein, the method for depolymerizing a compound of this embodiment may be referred to as “depolymerization method (1).”

[0510] The depolymerization method of this embodiment (depolymerization method (1)) is a novel method for depolymerizing (decomposing) compounds (1) including super engineering plastics.

[0511] The Ar １is a group represented by the general formula (91), the compound (1) includes polysulfone (sometimes referred to as "PSU" in this specification) and its derivatives.

[0512] The Ar １ In the case where is a group represented by the general formula (92), the compound (1) includes polyether ether sulfone (sometimes referred to as "PEES" in this specification) and its derivatives.

[0513] The Ar １ In the case where is a group represented by the general formula (93), the compound (1) includes polyphenylsulfone (sometimes referred to as "PPSU" in this specification) and its derivatives.

[0514] In this specification, when a structure in which one or more hydrogen atoms in a certain specific compound are substituted with a group other than a hydrogen atom is assumed, the compound having such a substituted structure is referred to as a "derivative" of the above-mentioned specific compound.

[0515] In this specification, unless otherwise specified, the term "group" includes not only an atomic group formed by bonding multiple atoms but also a single atom.

[0516] Ar １ is a group represented by the general formula (91), the depolymerization method (1) is a method for depolymerizing a group represented by the following general formula (1-1): (In the formula, n １ , Z １１ , Z １２ , m １１ , m １２ , X １１ , X １２ , l １１ and l １２ is the same as above.) is depolymerized in the presence of a hydroxide to obtain a compound represented by the following general formula (11):

[0517] (In the formula, Z １１ , Z １２ , m １１ and m １２ is the same as above.) or a salt thereof with a compound represented by the following general formula (121):

[0518] (In the formula, X １１ , X １２ , l １１ and l １２ is the same as above.) (compound (121)) or a salt thereof is obtained.

[0519] Ar １ is a group represented by the general formula (92), the depolymerization method (1) is a method for depolymerizing a group represented by the following general formula (1-2):

[0520] (In the formula, n １ , Z １１ , Z １２ , m １１ , m １２ , X ２１ and l ２１ is the same as above.) is depolymerized in the presence of a hydroxide to obtain a compound represented by the following general formula (11):

[0521] (In the formula, Z １１ , Z １２ , m １１ and m １２ is the same as above.) or a salt thereof with a compound represented by the following general formula (122):

[0522] (In the formula, X ２１ and l ２１ is the same as above.) (compound (122)) or a salt thereof is obtained.

[0523] Ar １ is a group represented by the general formula (93), the depolymerization method (1) comprises reacting a group represented by the following general formula (1-3): (In the formula, n １ , Z １１ , Z １２ , m １１ , m １２ , X ３１ , X ３２ , l ３１ and l ３２is the same as above.) is depolymerized in the presence of a hydroxide to obtain a compound represented by the following general formula (11):

[0524] (In the formula, Z １１ , Z １２ , m １１ and m １２ is the same as above.) or a salt thereof with a compound represented by the following general formula (123):

[0525] (In the formula, X ３１ , X ３２ , l ３１ and l ３２ is the same as above.) (compound (123)) or a salt thereof is obtained.

[0526] <Compound (1)> Compound (1) is the target of depolymerization in the depolymerization method (1).

[0527] In general formula (1), n １ is the number of repeating units, which defines the molecular size of compound (1), and is an integer of 2 or more.

[0528] n １ However, for example, compound (1) having a molecular weight of 35 to 150 is suitable as a high-molecular-weight super engineering plastic such as polysulfone (PSU), polyether ether sulfone (PEES), or polyphenyl sulfone (PPSU), which are difficult to depolymerize by conventional methods and are particularly suitable as targets for the depolymerization method (1).

[0529] In general formula (1), Z １１ and Z １２ are each independently a group other than a hydrogen atom (sometimes referred to as a "substituent" in this specification). １１ and Z １２ may be the same as or different from each other.

[0530] Z １１ and Z １２Examples of the (substituent) include an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, and a fluorine atom.

[0531] Z １１ and Z １２ The alkyl group in may be linear, branched, or cyclic, and may have both a chain structure (linear or branched) and a cyclic structure. In this specification, an alkyl group having a cyclic structure is considered to be a cyclic alkyl group regardless of whether or not it further has a chain structure. The cyclic structure in a cyclic alkyl group (an alkyl group having a cyclic structure but not a chain structure, and an alkyl group having both a cyclic structure and a chain structure) may be either monocyclic or polycyclic.

[0532] Z １１ and Z １２ The alkyl group preferably has 1 to 15 carbon atoms.

[0533] Z １１ and Z １２ Among the alkyl groups in the above, examples of the chain (linear or branched) alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a 1-methylbutyl group, an n-hexyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, an n-heptyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,2-dimethylbutyl group, a 2,3-dimethylbutyl group, an n-heptyl group, a 2-methylpentyl group, a 3-methylpentyl group, a 2,3-dimethylbutyl ...

[0033] Examples of the alkyl group include linear alkyl groups having 1 to 15 carbon atoms, such as an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a 2,2-dimethylpentyl group, a 2,3-dimethylpentyl group, a 2,4-dimethylpentyl group, a 3,3-dimethylpentyl group, a 3-ethylpentyl group, a 2,2,3-trimethylbutyl group, an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, a 3,7-dimethyloctyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group.

[0534] Z １１ and Z １２Among the alkyl groups in the above formula, examples of the cyclic alkyl group (an alkyl group having a monocyclic or polycyclic structure) include cyclic alkyl groups having 3 to 15 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a norbornyl group, an isobornyl group, a 1-adamantyl group, a 2-adamantyl group, a tricyclodecyl group, and cyclopropylmethyl.

[0535] Z １１ and Z １２ The alkyl group in the formula (I) may be, for example, any of an alkyl group having 1 to 10 carbon atoms (a linear alkyl group having 1 to 10 carbon atoms or a cyclic alkyl group having 3 to 10 carbon atoms), an alkyl group having 1 to 8 carbon atoms (a linear alkyl group having 1 to 8 carbon atoms or a cyclic alkyl group having 3 to 8 carbon atoms), an alkyl group having 1 to 6 carbon atoms (a linear alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms), and an alkyl group having 1 to 3 carbon atoms.

[0536] Z １１ and Z １２ The alkylcarbonylamino group (general formula: —NH—C(═O)—R ０１ (In the formula, R ０１ is an alkyl group.)) includes, for example, the above-mentioned Z １１ and Z １２ and monovalent groups having a structure in which a carbon atom having a free valence in the alkyl group is bonded to a carbon atom in a carbonylamino group (—NH—C(═O)—).

[0537] An example of the alkylcarbonylamino group is a methylcarbonylamino group (—NH—C(═O)—CH ３ ) and the like, but are not limited to these.

[0538] Z １１ and Z １２ The alkylcarbonylamino group in the formula (I) preferably has 2 to 16 carbon atoms.

[0539] Z １１ and Z １２Examples of the fluorinated alkyl group in １１ and Z １２ and monovalent groups having a structure in which one or more hydrogen atoms (—H) in the alkyl group are substituted with fluorine atoms (—F).

[0540] In the fluorinated alkyl group, the number of fluorine atoms depends on the number of carbon atoms in the fluorinated alkyl group and is not particularly limited, and may be, for example, 1 to 3. The fluorinated alkyl group may be, for example, a perfluoroalkyl group (a monovalent group having a structure in which all hydrogen atoms in an alkyl group are substituted with fluorine atoms) such as a trifluoromethyl group.

[0541] Z １１ and Z １２ The fluorinated alkyl group preferably has 1 to 15 carbon atoms.

[0542] In general formula (1), m １１ is a Z bonded to one benzene ring skeleton. １１ The number of m １２ Is Z １１ Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which １２ The number of m １１ and m １２ are each independently an integer of 0 to 4. That is, m １１ and m １２ may be the same as or different from each other.

[0543] Compound (1) has n １ ×m １１ Z １１ and m １１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×m １１ Z １１ may be the same or different. １１ is an integer equal to or greater than 1, １ ×m １１ Z １１may all be the same, may all be different, or may only be partially the same.

[0544] Z １２ The same applies to the case where compound (1) has n １ ×m １２ Z １２ and m １２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×m １２ Z １２ may be the same or different. １２ is an integer equal to or greater than 1, １ ×m １２ Z １２ may all be the same, may all be different, or may only be partially the same.

[0545] In general formula (1), Ar １ is a group represented by the general formula (91), a group represented by the general formula (92), or a group represented by the general formula (93).

[0546] In these groups, the bond marked with * is formed with one of the oxygen atoms that is not bonded to the sulfur atom (S) in general formula (1), and the bond marked with ** is formed with the other oxygen atom that is not bonded to the sulfur atom in general formula (1).

[0547] In the general formula (91), X １１ and X １２ are each independently a group (substituent) other than a hydrogen atom. １１ and X １２ may be the same as or different from each other.

[0548] X １１ and X １２ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0549] In general formula (91), l １１is an X bonded to one benzene ring skeleton. １１ is the number of １２ is X １１ X bonded to another benzene ring skeleton different from the benzene ring skeleton to which １２ is the number of １１ and l １２ are each independently an integer of 0 to 4. That is, l １１ and l １２ may be the same as or different from each other.

[0550] Compound (1) has n １ ×l １１ X of pieces １１ and l １１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l １１ X of pieces １１ may be the same or different from each other. １１ is an integer equal to or greater than 1, １ ×l １１ X of pieces １１ may all be the same, may all be different, or may only be partially the same.

[0551] X １２ The same applies to the case where compound (1) has n １ ×l １２ X of pieces １２ and l １２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l １２ X of pieces １２ may be the same or different from each other. １２ is an integer equal to or greater than 1, １ ×l １２ X of pieces １２ may all be the same, may all be different, or may only be partially the same.

[0552] In general formula (91), l １１ and l １２may be, for example, independently any of 0 to 3, 0 to 2, 0 to 1, and 0.

[0553] A preferred example of the group represented by general formula (91) is l １１ and l １２ is 0 (i.e., X １１ and X １２ (not having) groups.

[0554] In the general formula (92), X ２１ is a group (substituent) other than a hydrogen atom.

[0555] X ２１ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0556] In general formula (92), l ２１ is an X bonded to one benzene ring skeleton. ２１ and is an integer from 0 to 4.

[0557] Compound (1) has n １ ×l ２１ X of pieces ２１ and l ２１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l ２１ X of pieces ２１ may be the same or different from each other. ２１ is an integer equal to or greater than 1, １ ×l ２１ X of pieces ２１ may all be the same, may all be different, or may only be partially the same.

[0558] In general formula (92), l ２１ may be, for example, 0 to 3, 0 to 2, 0 to 1, or 0.

[0559] A preferred example of the group represented by the general formula (92) is l ２１ is 0 (i.e., X ２１(not having) groups.

[0560] In the general formula (93), X ３１ and X ３２ are each independently a group (substituent) other than a hydrogen atom. ３１ and X ３２ may be the same as or different from each other.

[0561] X ３１ and X ３２ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0562] In general formula (93), l ３１ is an X bonded to one benzene ring skeleton. ３１ is the number of ３２ is X ３１ X bonded to another benzene ring skeleton different from the benzene ring skeleton to which ３２ is the number of ３１ and l ３２ are each independently an integer of 0 to 4. That is, l ３１ and l ３２ may be the same as or different from each other.

[0563] Compound (1) has n １ ×l ３１ X of pieces ３１ and l ３１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l ３１ X of pieces ３１ may be the same or different from each other. ３１ is an integer equal to or greater than 1, １ ×l ３１ X of pieces ３１ may all be the same, may all be different, or may only be partially the same.

[0564] X ３２The same applies to the case where compound (1) has n １ ×l ３２ X of pieces ３２ and l ３２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), １ ×l ３２ X of pieces ３２ may be the same or different from each other. ３２ is an integer equal to or greater than 1, １ ×l ３２ X of pieces ３２ may all be the same, may all be different, or may only be partially the same.

[0565] In general formula (93), l ３１ and l ３２ may be, for example, independently any of 0 to 3, 0 to 2, 0 to 1, and 0.

[0566] A preferred example of the group represented by general formula (93) is l ３１ and l ３２ is 0 (i.e., X ３１ and X ３２ (not having) groups.

[0567] An example of a preferred compound (1) is Ar １ is any of a group represented by general formula (91), a group represented by general formula (92), and a group represented by general formula (93), m １１ and m １２ is 0 (i.e., Z １１ and Z １２ Compound (1) does not have the formula:

[0568] A more preferred example of the compound (1) is Ar １ is a group represented by general formula (91), and l １１ and l １２ is 0, and m １１ and m １２ is 0.

[0569] Other examples of more preferred compounds (1) include Ar １is a group represented by general formula (92), and l ２１ is 0, and m １１ and m １２ is 0.

[0570] Further examples of more preferred compounds (1) include Ar １ is a group represented by general formula (93), and l ３１ and l ３２ is 0, and m １１ and m １２ is 0.

[0571] However, compound (1) is not limited to these.

[0572] The hydrogen atom in one (one) or both (two) hydroxyl groups (-OH, hydroxyl groups at one or both ends in general formula (1)) in compound (1) may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-OM", as in the case of compound (11) described below. That is, compound (1) may be a salt.

[0573] <Compound (11)> Compound (11) is one of the products obtained by the depolymerization method (1).

[0574] Compound (11) is bisphenol S (sometimes referred to as "BPS" in this specification) and its derivatives.

[0575] Z in general formula (11) １１ , Z １２ , m １１ and m １２ respectively represent Z in general formula (1). １１ , Z １２ , m １１ and m １２ <Compound (121)> Compound (121) is the same as Ar １ is a group represented by general formula (91), the other product of the depolymerization method (1).

[0576] Compound (121) is bisphenol A (sometimes referred to as "BPA" in this specification) and its derivatives.

[0577] X in general formula (121) １１ , X １２ , l １１ and l １２ respectively represent X in general formula (91). １１ , X １２ , l １１ and l １２ <Compound (122)> Compound (122) is the same as Ar １ is a group represented by general formula (92), the other product of the depolymerization method (1).

[0578] Compound (122) is hydroquinone and its derivatives.

[0579] X in general formula (122) ２１ and l ２１ respectively represent X in general formula (92). ２１ and l ２１ is the same as

[0580] <Compound (123)> Compound (123) is a compound of Ar １ is a group represented by general formula (93), the other product of the depolymerization method (1).

[0581] The compound (123) is 4,4'-biphenol (also known as 4,4'-dihydroxybiphenyl) and its derivatives.

[0582] X in general formula (123) ３１ , X ３２ , l ３１ and l ３２ respectively represent X in general formula (93). ３１ , X ３２ , l ３１ and l ３２ is the same as

[0583] <Salt of Compound (11), Salt of Compound (121), Salt of Compound (122), Salt of Compound (123)> The salt of compound (11) is a compound in which the hydrogen atom in one (1) or both (2) hydroxyl groups (-OH) in compound (11) is substituted with a group other than a hydrogen atom (hereinafter represented by the symbol "M") to form a group represented by the formula "-OM". The formula "-OM" can be, for example, a group represented by the formula "-O － M ＋" can also be expressed as ".

[0584] When the hydrogen atoms of both hydroxyl groups in compound (11) are substituted with the above M, these two Ms may be the same or different.

[0585] The presence or absence of substitution of a hydrogen atom by M and, if substituted, the type of M are determined, for example, by the conditions for post-treatment of the reaction solution after depolymerization of compound (1). For example, when the reaction solution after depolymerization of compound (1) is treated with an acid, compound (11) is obtained as the main component, rather than a salt of compound (11).

[0586] Examples of M include those derived from hydroxides (which serve as counter cations) as described below, and are preferably metal atoms (the salt of compound (11) is an alkoxide).

[0587] The mode in which compound (121), compound (122), and compound (123) form salts is the same as the mode in which compound (11) forms a salt. That is, the salts of compound (121), compound (122), and compound (123) are also formed in the same manner as the salt of compound (11), and are the same as the salt of compound (11) except that the group to which the group represented by the formula "-OM" is bonded is different.

[0588] <Hydroxide> The hydroxide is a hydroxide ion (OH － The hydroxide is not particularly limited as long as it is a compound having the formula (a compound that generates hydroxide ions when dissolved in water), and may be either an organic hydroxide or an inorganic hydroxide.

[0589] Examples of the organic hydroxide include ammonium hydroxide salts and phosphonium hydroxide salts.

[0590] Examples of the ammonium hydroxide salt include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide and tetrabutylammonium hydroxide.

[0591] Examples of the phosphonium hydroxide salt include tetraalkylphosphonium hydroxides such as tetrabutylphosphonium hydroxide.

[0592] Examples of the inorganic hydroxide include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide monohydrate, hydrates of cesium hydroxide other than the monohydrate, and anhydrous cesium hydroxide.

[0593] The above-mentioned hydrates other than cesium hydroxide monohydrate refer to cesium hydroxide hydrates having two or more water molecules in one molecule (one example is cesium hydroxide dihydrate).

[0594] The hydroxide used in the depolymerization step is preferably an alkali metal hydroxide.

[0595] In the depolymerization step, it is preferable to use a hydroxide that has been dried by heating under reduced pressure. This enhances the effect obtained by using the hydroxide, and makes the depolymerization of compound (1) particularly easy to proceed. This is presumably because, while the presence of water makes it difficult for the depolymerization of compound (1) to proceed, the water content of the hydroxide can be reduced by drying it by heating under reduced pressure.

[0596] The hydroxide is preferably dried by heating under a pressure of 1333.22 Pa (10 mmHg) or less, more preferably 666.61 Pa (5 mmHg) or less, and even more preferably 399.966 Pa (3 mmHg) or less. When the pressure during reduced pressure is equal to or less than the upper limit, the degree of dryness of the hydroxide is further improved.

[0597] On the other hand, hydroxides are preferably dried by heating under a pressure of, for example, 133.322 Pa (1 mmHg) or more, as this reduced pressure can be more easily achieved.

[0598] The drying temperature (heating temperature) when the hydroxide is heated and dried under reduced pressure is preferably 100° C. or higher, more preferably 120° C. or higher, and even more preferably 140° C. or higher. When the drying temperature is equal to or higher than the lower limit, the dryness of the hydroxide is further improved.

[0599] On the other hand, the drying temperature is preferably not more than 180° C. By setting the drying temperature in this manner, excessive heating is suppressed.

[0600] The drying time (heating time) when the hydroxide is dried by heating under reduced pressure can be adjusted appropriately depending on the pressure at the time of reduced pressure and the drying temperature. For example, when the pressure at the time of reduced pressure and the drying temperature are both within the above-mentioned ranges, the drying time is preferably 2 to 8 hours. When the drying time is equal to or greater than the lower limit, the degree of dryness of the hydroxide is further improved. When the drying time is equal to or less than the upper limit, excessive heating is suppressed.

[0601] When a hydrate such as cesium hydroxide monohydrate is used as the hydroxide, the hydrate can be anhydrified by heating and drying under reduced pressure (for example, to form anhydrous cesium hydroxide), and this can be used in the depolymerization step. Alternatively, the hydrate can be used in the depolymerization step in a state that is not anhydrified by heating and drying under reduced pressure (i.e., in the hydrate state). For example, part or all of the hydrates other than the above-mentioned cesium hydroxide monohydrate can be converted to cesium hydroxide monohydrate by heating and drying under reduced pressure, and this cesium hydroxide monohydrate can be used in the depolymerization step.

[0602] The hydroxide used in the depolymerization step may be one type only, or two or more types may be used. When two or more types are used, the combination and ratio thereof can be selected arbitrarily depending on the purpose.

[0603] For example, when a hydrate such as cesium hydroxide monohydrate is dried by heating under reduced pressure as the hydroxide, a mixture of the hydrate of the hydroxide and the anhydrous hydroxide may be obtained. In the depolymerization step, a mixture of such a hydrate and anhydrous hydroxide may be used as the hydroxide. When a hydrate other than cesium hydroxide monohydrate is dried by heating under reduced pressure, a mixture of cesium hydroxide monohydrate and anhydrous cesium hydroxide may be obtained. In the depolymerization step, such a mixture may be used as the hydroxide.

[0604] In the depolymerization step, the amount of hydroxide used is determined by the ratio of the repeating unit in compound (1) (symbol n in general formula (1)). １ The amount of hydroxide used is preferably 2 to 8 times the number of moles of the structural unit (the structural unit marked with ""), and may be, for example, 3 to 6 times or 3.5 to 4.5 times the number of moles. When the amount of hydroxide used is equal to or greater than the lower limit, depolymerization of compound (1) proceeds more easily. When the amount of hydroxide used is equal to or less than the upper limit, excessive use of hydroxide is suppressed.

[0605] <Solvent> In the depolymerization step, it is preferable to further use a solvent. By using a solvent, particularly by dissolving compound (1) in a solvent and carrying out the depolymerization step, the depolymerization of compound (1) can more easily proceed.

[0606] In this specification, unless otherwise specified, the term "solvent" is a concept that encompasses both a component that is liquid at room temperature and that dissolves a solute, and a component that is liquid at room temperature and that functions as a dispersion medium for dispersing a dispersoid. Furthermore, "room temperature" means a temperature that is not particularly cooled or heated, i.e., an ordinary temperature, and examples thereof include a temperature of 15 to 25°C.

[0607] The solvent is preferably an organic solvent.

[0608] Examples of the organic solvent include amides such as 1,3-dimethyl-2-imidazolidinone (DMI), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP); nitriles such as benzonitrile; and ethers (cyclic ethers) such as 1,4-dioxane.

[0609] The solvent used in the depolymerization step may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0610] When a solvent is used in the depolymerization step, the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (1), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.5 to 1.5 L, and 0.7 to 1.5 L. When the amount of solvent used is equal to or greater than the lower limit, the depolymerization of compound (1) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0611] <Dehydrating Agent> In the depolymerization step, it is preferable to further use a dehydrating agent. In the depolymerization step, the presence of water makes it difficult for the depolymerization of compound (1) to proceed. That is, by using a dehydrating agent in the depolymerization step, the depolymerization of compound (1) proceeds more easily, and the yield of compound (11) or a salt thereof, and the yield of compound (121), compound (122), or compound (123) or a salt thereof are increased.

[0612] The dehydrating agent may be a water-reactive component that reacts with water to form another component, or a hygroscopic component that does not react with water but adsorbs water (in other words, absorbs moisture).

[0613] Examples of the water-reactive component include sodium hydride (NaH), potassium hydride (KH), and calcium hydride (CaH ２ ), calcium oxide (CaO), cesium chloride (CsCl ２ ), calcium chloride (CaCl ２ ), magnesium sulfate (MgSO ４ ) etc.

[0614] The hygroscopic component may be, for example, zeolite, etc. As the zeolite, a commercially available product under the trade name of molecular sieve can be used.

[0615] The dehydrating agent used in the depolymerization step may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0616] The dehydrating agent used in the depolymerization step is preferably one or more selected from the group consisting of sodium hydride, potassium hydride, calcium hydride, calcium oxide, cesium chloride, calcium chloride, magnesium sulfate, and zeolite.

[0617] In the case where a dehydrating agent is used in the depolymerization step, the amount of the dehydrating agent used is determined based on the repeating unit in the compound (1) (the symbol n １ The molar amount of the dehydrating agent is preferably 2 to 8 times, for example, 4 to 6 times, or 3.5 to 4.5 times, the number of moles of the structural unit (the structural unit marked with "") (the structural unit marked with ""). When the amount of the dehydrating agent used is equal to or greater than the lower limit, the depolymerization of compound (1) is more likely to proceed. When the amount of the dehydrating agent used is equal to or less than the upper limit, excessive use of the dehydrating agent is suppressed.

[0618] <Other Components> In the depolymerization step, compound (1) may be depolymerized using another component that does not fall into any of compound (1), a hydroxide, optionally a solvent, and optionally a dehydrating agent, within a range that does not impair the effects of the present invention, or compound (1) may be depolymerized without using the other component.

[0619] The other components can be selected arbitrarily depending on the purpose and are not particularly limited.

[0620] The other component used in the depolymerization step may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0621] When depolymerizing compound (1) in the depolymerization step, the ratio of the total amount (parts by mass) of the hydroxide, solvent, and dehydrating agent to the total amount (parts by mass) of the hydroxide, solvent, dehydrating agent, and other components (([amount (parts by mass) of hydroxide] + [amount (parts by mass) of solvent] + [amount (parts by mass) of dehydrating agent]) / ([amount (parts by mass) of hydroxide] + [amount (parts by mass) of solvent] + [amount (parts by mass) of dehydrating agent] + [amount (parts by mass) of other components]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When the ratio is equal to or greater than the lower limit, the depolymerization of compound (1) proceeds more easily.

[0622] On the other hand, the proportion is 100% by mass or less.

[0623] When depolymerizing compound (1), if no optional component (i.e., a solvent, a dehydrating agent, or the other component) is used, the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0624] <Other Conditions> In the depolymerization step, compound (1), a hydroxide, optionally a solvent, optionally a dehydrating agent, and optionally the other components are mixed, and the resulting mixture is heated and stirred, thereby depolymerizing compound (1).

[0625] In the depolymerization step, the temperature (reaction temperature) when the mixture is heated and stirred is preferably 100° C. or higher, more preferably 115° C. or higher, and may be, for example, any one of 130° C. or higher and 145° C. or higher. When the reaction temperature is equal to or higher than the lower limit, the depolymerization of compound (1) proceeds more easily.

[0626] On the other hand, the reaction temperature is preferably 170° C. or less in terms of suppressing the by-production of impurities.

[0627] In the depolymerization step, the time (reaction time) for heating and stirring the mixture is preferably 10 to 40 hours, and may be, for example, either 10 to 24 hours or 24 to 40 hours.

[0628] The above reaction times are particularly suitable when the reaction temperature is within the above range.

[0629] In the depolymerization step, the depolymerization of compound (1) is preferably carried out under an atmosphere of an inert gas such as argon gas, helium gas, or nitrogen gas. This reduces the amount of water in the mixture, and provides the same effect as when a dehydrating agent is used. That is, the depolymerization of compound (1) proceeds more easily, and the yield of compound (11) or a salt thereof, and the yield of compound (121), compound (122), or compound (123) or a salt thereof are increased.

[0630] In the depolymerization step, it is more preferable to carry out the depolymerization of compound (1) using a dehydrating agent under the inert gas atmosphere, more preferable to carry out the depolymerization of compound (1) using a hydroxide that has been dried by heating under reduced pressure under the inert gas atmosphere, and even more preferable to carry out the depolymerization of compound (1) using a dehydrating agent and a hydroxide that has been dried by heating under reduced pressure under the inert gas atmosphere. By doing so, the yield of the target product (compound (11) or a salt thereof, and compound (121), compound (122), or compound (123) or a salt thereof) can be further increased.

[0631] In the depolymerization method (1), after completion of the depolymerization step, the resulting reaction mixture can be post-treated as needed by a known method to isolate the target product (product). That is, post-treatment procedures such as filtration, washing, extraction, pH adjustment, dehydration, and concentration can be performed, either alone or in combination, as needed, and the target product can be isolated by concentration, crystallization, reprecipitation, column chromatography, or the like. Furthermore, the isolated target product can be further purified, as needed, by performing one or more operations, either alone or in combination, of crystallization, reprecipitation, column chromatography, extraction, stirring and washing of crystals with a solvent. Alternatively, after completion of the depolymerization step, the resulting reaction mixture can be post-treated as needed, and then used for the next intended application without isolating the target product. For example, the target product can be subjected to the next intended reaction without being isolated.

[0632] The structure of the product obtained by the depolymerization method (1) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0633] <<Depolymerization Method (2)>> A method for depolymerizing a compound according to one embodiment of the present invention is a method for depolymerizing a compound represented by the following general formula (2): (In the formula, n ２ is an integer of 2 or more (preferably, 10 to 200); Z ２１ , Z ２２ and Z ２３ are each independently a group other than a hydrogen atom; m ２１ , m ２２ and m ２３ are each independently an integer of 0 to 4, and m ２１ When n is an integer of 1 or more, ２ ×m ２１ Z ２１ may be the same or different, m ２２ When n is an integer of 1 or more, ２ ×m ２２ Z ２２ may be the same or different, m ２３ When n is an integer of 1 or more, ２ ×m２３ Z ２３ may be the same or different.) (hereinafter, may be referred to as “compound (2)”) is depolymerized in the presence of a hydroxide to obtain a compound represented by the following general formula (21):

[0634] (In the formula, Z ２１ , Z ２２ , m ２１ and m ２２ are the same as above.) or a salt thereof (hereinafter, may be referred to as "compound (21)") and a compound represented by the following general formula (22):

[0635] (In the formula, Z ２３ and m ２３ are the same as above.) (herein, this method may be referred to as "compound (22)") or a salt thereof. Herein, this method for depolymerizing a compound of the present embodiment may be referred to as "depolymerization method (2)."

[0636] The depolymerization method of this embodiment (depolymerization method (2)) is a novel method for depolymerizing compounds (2) including super engineering plastics.

[0637] The depolymerization method (2) is the same as the depolymerization method (1) except that the compound (2) is used instead of the compound (1), that is, the target of depolymerization is different.

[0638] The compound (2) includes polyether ether ketone (sometimes referred to as "PEEK" in this specification) and its derivatives. <Compound (2)> Compound (2) is the target of depolymerization in the depolymerization method (2).

[0639] In general formula (2), n ２ is the number of repeating units, which defines the molecular size of compound (2), and is an integer of 2 or more.

[0640] n ２However, for example, compound (2) having a molecular weight of 20 to 100 is suitable for polyether ether ketone (PEEK), a high-molecular-weight super engineering plastic, which is difficult to depolymerize by conventional methods and is particularly suitable as an application target of depolymerization method (2).

[0641] In general formula (2), Z ２１ , Z ２２ and Z ２３ are each independently a group (substituent) other than a hydrogen atom. ２１ , Z ２２ and Z ２３ may all be the same, may all be different, or only some (any two types) may be the same.

[0642] Z ２１ , Z ２２ and Z ２３ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0643] In general formula (2), m ２１ is a Z bonded to one benzene ring skeleton. ２１ The number of m ２２ Is Z ２１ Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which ２２ The number of m ２３ Is Z ２１ and a benzene ring skeleton to which Z is bonded. ２２ and Z bonded to another benzene ring skeleton different from either of ２３ is the number of

[0644] m ２１ , m ２２ and m ２３ are each independently an integer of 0 to 4. That is, m ２１ , m ２２ and m ２３may all be the same, may all be different, or only some (any two types) may be the same.

[0645] Compound (2) has n ２ ×m ２１ Z ２１ and m ２１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ２ ×m ２１ Z ２１ may be the same or different. ２１ is an integer equal to or greater than 1, ２ ×m ２１ Z ２１ may all be the same, may all be different, or may only be partially the same.

[0646] Z ２２ The same applies to the case where compound (2) has n ２ ×m ２２ Z ２２ and m ２２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ２ ×m ２２ Z ２２ may be the same or different. ２２ is an integer equal to or greater than 1, ２ ×m ２２ Z ２２ may all be the same, may all be different, or may only be partially the same.

[0647] Z ２３ The same applies to the case where compound (2) has n ２ ×m ２３ Z ２３ and m ２３ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ２ ×m ２３ Z ２３ may be the same or different. ２３ is an integer equal to or greater than 1, ２ ×m２３ Z ２３ may all be the same, may all be different, or may only be partially the same.

[0648] An example of a preferred compound (2) is m ２１ , m ２２ and m ２３ is 0 (i.e., Z ２１ , Z ２２ and Z ２３ Compound (2) does not have the formula:

[0649] However, the compound (2) is not limited to these.

[0650] The hydrogen atom in one (1) or both (2) hydroxyl groups (-OH, hydroxyl groups at one or both ends in general formula (2)) in compound (2) may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-OM", as in the case of compound (21) described below. That is, compound (2) may be a salt.

[0651] <Compound (21)> Compound (21) is one of the products obtained by the depolymerization method (2).

[0652] Compound (21) is 4,4'-dihydroxybenzophenone and its derivatives.

[0653] Z in general formula (21) ２１ , Z ２２ , m ２１ and m ２２ respectively represent Z in general formula (2). ２１ , Z ２２ , m ２１ and m ２２ is the same as

[0654] <Compound (22)> Compound (22) is the other product of the depolymerization method (2).

[0655] Compound (22) is 1,3-dihydroxybenzene (also known as resorcinol) and its derivatives.

[0656] Z in general formula (22) ２３ and m ２３ respectively represent Z in general formula (2).２３ and m ２３ is the same as

[0657] <Salt of Compound (21) and Salt of Compound (22)> Similar to the case of the compound (11), the salt of compound (21) is a salt of compound (22) in which the hydrogen atom in one (one) or both (two) hydroxyl groups (—OH) in compound (21) is replaced with a group (M) other than a hydrogen atom, and the salt is represented by the formula “—OM” (the formula “—O － M ＋ ") is a compound that forms a group represented by the formula:

[0658] When the hydrogen atoms of both hydroxyl groups in compound (21) are substituted with the above M, these two Ms may be the same or different.

[0659] The presence or absence of substitution of a hydrogen atom by M and, if substituted, the type of M are determined, for example, by the conditions for post-treatment of the reaction solution after depolymerization of compound (2). For example, when the reaction solution after depolymerization of compound (2) is treated with an acid, compound (21) is obtained as the main component, rather than a salt of compound (21).

[0660] The M is the same as in the salt of compound (11) above.

[0661] The mode in which compound (22) forms a salt is the same as the mode in which compound (21) forms a salt. That is, the salt of compound (22) is also formed in the same manner as the salt of compound (21), and is the same as the salt of compound (21) except that the group to which the group represented by the formula "-OM" is bonded is different.

[0662] <Hydroxide> The hydroxide in the depolymerization method (2) is the same as the hydroxide in the depolymerization method (1).

[0663] The hydroxides used in the depolymerization step of the depolymerization method (2) may be one type only or two or more types. When two or more types are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0664] The hydroxide used in the depolymerization step of the depolymerization method (2) is preferably an alkali metal hydroxide.

[0665] In the depolymerization step of the depolymerization method (2), it is preferable to use a hydroxide that has been dried by heating under reduced pressure, which enhances the effect obtained by using the hydroxide and makes it particularly easy for the depolymerization of compound (2) to proceed.

[0666] The hydroxide dried by heating under reduced pressure in the depolymerization method (2) is the same as the hydroxide dried by heating under reduced pressure in the depolymerization method (1), and is obtained by the same method as in the depolymerization method (1).

[0667] In the depolymerization step of the depolymerization method (2), the amount of hydroxide used is determined based on the repeating unit in the compound (2) (the symbol n ２ The amount of hydroxide used is preferably 2 to 8 times the number of moles of the structural unit (the structural unit marked with ""), and may be, for example, 3 to 6 times or 3.5 to 4.5 times the number of moles. When the amount of hydroxide used is equal to or greater than the lower limit, depolymerization of compound (2) proceeds more easily. When the amount of hydroxide used is equal to or less than the upper limit, excessive use of hydroxide is suppressed.

[0668] <Solvent> In the depolymerization step of the depolymerization method (2), it is preferable to further use a solvent. By using a solvent, particularly by dissolving the compound (2) in a solvent and carrying out the depolymerization step, the depolymerization of the compound (2) can more easily proceed.

[0669] The solvent in the depolymerization method (2) is the same as the solvent in the depolymerization method (1).

[0670] The solvent used in the depolymerization step of the depolymerization method (2) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0671] When a solvent is used in the depolymerization step of the depolymerization method (2), the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (2), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.5 to 1.5 L, and 0.7 to 1.5 L. When the amount of solvent used is equal to or greater than the lower limit, the depolymerization of compound (2) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0672] <Dehydrating Agent> In the depolymerization step of the depolymerization method (2), it is preferable to further use a dehydrating agent. In the depolymerization step, the presence of water makes it difficult for the depolymerization of compound (2) to proceed. That is, by using a dehydrating agent in the depolymerization step, the depolymerization of compound (2) proceeds more easily, and the yield of compound (21) or a salt thereof and the yield of compound (22) or a salt thereof are increased.

[0673] The dehydrating agent in the depolymerization method (2) is the same as the dehydrating agent in the depolymerization method (1).

[0674] The dehydrating agent used in the depolymerization step of the depolymerization method (2) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0675] The dehydrating agent used in the depolymerization step of the depolymerization method (2) is preferably one or more selected from the group consisting of sodium hydride, potassium hydride, calcium hydride, calcium oxide, cesium chloride, calcium chloride, magnesium sulfate, and zeolite.

[0676] In the case where a dehydrating agent is used in the depolymerization step of the depolymerization method (2), the amount of the dehydrating agent used is determined based on the repeating unit in the compound (2) (the symbol n ２The molar amount of the dehydrating agent is preferably 2 to 8 times, for example, 4 to 6 times, or 3.5 to 4.5 times, the number of moles of the structural unit (the structural unit marked with "") (the structural unit marked with ""). When the amount of the dehydrating agent used is equal to or greater than the lower limit, the depolymerization of compound (2) is more likely to proceed. When the amount of the dehydrating agent used is equal to or less than the upper limit, excessive use of the dehydrating agent is suppressed.

[0677] <Other Components> In the depolymerization step of the depolymerization method (2), the compound (2) may be depolymerized using another component that does not fall into any of the compound (2), a hydroxide, optionally a solvent, and optionally a dehydrating agent, within a range that does not impair the effects of the present invention, or the compound (2) may be depolymerized without using the other component.

[0678] The other components in the depolymerization method (2) are the same as the other components in the depolymerization method (1).

[0679] The other component used in the depolymerization step of the depolymerization method (2) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0680] When depolymerizing compound (2) in the depolymerization step of depolymerization method (2), the ratio of the total amount (parts by mass) of the hydroxide, solvent, and dehydrating agent to the total amount (parts by mass) of the hydroxide, solvent, dehydrating agent, and other components (([amount of hydroxide used (parts by mass)] + [amount of solvent used (parts by mass)] + [amount of dehydrating agent used (parts by mass)]) / ([amount of hydroxide used (parts by mass)] + [amount of solvent used (parts by mass)] + [amount of dehydrating agent used (parts by mass)] + [amount of other components used (parts by mass)]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When this ratio is equal to or greater than the lower limit, the depolymerization of compound (2) proceeds more easily.

[0681] On the other hand, the proportion is 100% by mass or less.

[0682] When depolymerizing compound (2), if no optional component (i.e., a solvent, a dehydrating agent, or the other component) is used, the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0683] <Other Conditions> In the depolymerization step of the depolymerization method (2), the compound (2), a hydroxide, and optionally a solvent, optionally a dehydrating agent, and optionally the other components are mixed, and the resulting mixture is heated and stirred, thereby depolymerizing the compound (2).

[0684] In the depolymerization step of the depolymerization method (2), the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (2) are the same as the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (1), respectively.

[0685] In the depolymerization step of the depolymerization method (2), it is more preferable to carry out the depolymerization of compound (2) using a dehydrating agent under the inert gas atmosphere, it is more preferable to carry out the depolymerization of compound (2) using a hydroxide that has been dried by heating under reduced pressure under the inert gas atmosphere, and it is even more preferable to carry out the depolymerization of compound (2) using a dehydrating agent and a hydroxide that has been dried by heating under reduced pressure under the inert gas atmosphere. By doing so, the yield of the target product (compound (21) or a salt thereof, and compound (22) or a salt thereof) can be further increased.

[0686] In the depolymerization method (2), after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (1), and the target substance (product) may be isolated, and the isolated target substance may be further purified, if necessary. Alternatively, after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (1), and then used for the next intended application without isolation of the target substance.

[0687] The structure of the product obtained by the depolymerization method (2) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0688] <<Depolymerization Method (4)>> A method for depolymerizing a compound according to one embodiment of the present invention is a method for depolymerizing a compound represented by the following general formula (4): (In the formula, n ４ is an integer of 2 or more (preferably, 10 to 200); Z ４１ and Z ４２ are each independently a group other than a hydrogen atom; m ４１ and m ４２ are each independently an integer of 0 to 4, and m ４１ When n is an integer of 1 or more, ４ ×m ４１ Z ４１ may be the same or different, m ４２ When n is an integer of 1 or more, ４ ×m ４２ Z ４２ may be the same or different.) (hereinafter, may be referred to as “compound (4)”) is depolymerized in the presence of a hydroxide to obtain a compound represented by the following general formula (41):

[0689] (In the formula, Z ４１ , Z ４２ , m ４１ and m ４２ are the same as above.) (herein, this method may be referred to as "compound (41)") or a salt thereof. Herein, this method for depolymerizing a compound of this embodiment may be referred to as "depolymerization method (4)."

[0690] The depolymerization method of this embodiment (depolymerization method (4)) is a novel method for depolymerizing compounds (4) including super engineering plastics.

[0691] The depolymerization method (4) is the same as the depolymerization method (1) except that the compound (4) is used instead of the compound (1), that is, the target of depolymerization is different.

[0692] The compound (4) includes polyethersulfone (sometimes referred to as "PESU" in this specification) and its derivatives.

[0693] <Compound (4)> Compound (4) is the target of depolymerization in the depolymerization method (4).

[0694] In general formula (4), n ４ is the number of repeating units, which defines the molecular size of compound (4), and is an integer of 2 or more.

[0695] n ４ However, for example, compound (4) having a molecular weight of 30 to 350 is suitable as polyethersulfone (PESU), a high-molecular-weight super engineering plastic, which is difficult to depolymerize by conventional methods and is particularly suitable as an application target of depolymerization method (4).

[0696] In general formula (4), Z ４１ and Z ４２ are each independently a group (substituent) other than a hydrogen atom. ４１ and Z ４２ may be the same as each other or may be different from each other.

[0697] Z ４１ and Z ４２ (Substituent) may be, for example, the above Z １１ and Z １２ (for example, an alkyl group, an alkylcarbonylamino group, a fluorinated alkyl group, a fluorine atom, etc.)

[0698] In general formula (4), m ４１ is a Z bonded to one benzene ring skeleton. ４１ The number of m ４２ Is Z ４１ Z is bonded to another benzene ring skeleton different from the benzene ring skeleton to which ４２ is the number of

[0699] m ４１ and m ４２ are each independently an integer of 0 to 4. That is, m ４１ and m ４２may be the same as each other or may be different from each other.

[0700] Compound (4) has n ４ ×m ４１ Z ４１ and m ４１ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ４ ×m ４１ Z ４１ may be the same or different. ４１ is an integer equal to or greater than 1, ４ ×m ４１ Z ４１ may all be the same, may all be different, or may only be partially the same.

[0701] Z ４２ The same applies to the case of compound (4), and compound (4) has n ４ ×m ４２ Z ４２ and m ４２ When n is an integer of 1 or more (i.e., an integer of 1 to 4), ４ ×m ４２ Z ４２ may be the same or different. ４２ is an integer equal to or greater than 1, ４ ×m ４２ Z ４２ may all be the same, may all be different, or may only be partially the same.

[0702] An example of a preferred compound (4) is m ４１ and m ４２ is 0 (i.e., Z ４１ and Z ４２ Compound (4) does not have the formula:

[0703] However, compound (4) is not limited to these.

[0704] The hydrogen atom in one (1) or both (2) hydroxyl groups (-OH, hydroxyl groups at one or both ends in general formula (4)) in compound (4) may be substituted with a group (M) other than a hydrogen atom to form a group represented by the formula "-OM", as in the case of compound (41) described later. That is, compound (4) may be a salt.

[0705] <Compound (41)> Compound (41) is a product of the depolymerization method (4).

[0706] Compound (41) is bisphenol S (BPS) and its derivatives.

[0707] Z in general formula (41) ４１ , Z ４２ , m ４１ and m ４２ respectively represent Z in general formula (4). ４１ , Z ４２ , m ４１ and m ４２ <Salt of Compound (41)> Similar to the case of the compound (11), the salt of compound (41) is a salt of a compound (41) in which the hydrogen atom in one (1) or both (2) hydroxyl groups (-OH) in the compound (41) is replaced with a group (M) other than a hydrogen atom, and the salt is represented by the formula "-OM" (the formula "-O － M ＋ ") is a compound that forms a group represented by the formula:

[0708] When the hydrogen atoms of both hydroxyl groups in compound (41) are substituted with the above M, these two Ms may be the same or different.

[0709] The presence or absence of substitution of a hydrogen atom by M and, if substituted, the type of M are determined, for example, by the conditions for post-treatment of the reaction solution after depolymerization of compound (4). For example, when the reaction solution after depolymerization of compound (4) is treated with an acid, compound (41) is obtained as the main component, rather than a salt of compound (41).

[0710] The M is the same as in the salt of the compound (41) above.

[0711] <Hydroxide> The hydroxide in the depolymerization method (4) is the same as the hydroxide in the depolymerization method (1).

[0712] The hydroxides used in the depolymerization step of the depolymerization method (4) may be one type only or two or more types. When two or more types are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0713] The hydroxide used in the depolymerization step of the depolymerization method (4) is preferably an alkali metal hydroxide.

[0714] In the depolymerization step of the depolymerization method (4), it is preferable to use a hydroxide that has been dried by heating under reduced pressure, which enhances the effect obtained by using the hydroxide and makes the depolymerization of the compound (4) particularly easy to proceed.

[0715] The hydroxide dried by heating under reduced pressure in the depolymerization method (4) is the same as the hydroxide dried by heating under reduced pressure in the depolymerization method (1), and is obtained by the same method as in the depolymerization method (1).

[0716] In the depolymerization step of the depolymerization method (4), the amount of hydroxide used is determined based on the repeating unit in the compound (4) (the symbol n ４ The amount of hydroxide used is preferably 2 to 8 times the number of moles of the structural unit (the structural unit marked with ""), and may be, for example, 2 to 6 times or 2 to 4.5 times the number of moles. When the amount of hydroxide used is equal to or greater than the lower limit, depolymerization of compound (4) proceeds more easily. When the amount of hydroxide used is equal to or less than the upper limit, excessive use of hydroxide is suppressed.

[0717] <Solvent> In the depolymerization step of the depolymerization method (4), it is preferable to further use a solvent. By using a solvent, particularly by dissolving the compound (4) in a solvent and carrying out the depolymerization step, the depolymerization of the compound (4) can more easily proceed.

[0718] The solvent in the depolymerization method (4) is the same as the solvent in the depolymerization method (1).

[0719] The solvent used in the depolymerization step of the depolymerization method (4) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0720] When a solvent is used in the depolymerization step of the depolymerization method (4), the amount of solvent used is preferably 0.2 to 1.5 L relative to 100 g of compound (4), and may be, for example, any of 0.2 to 1 L, 0.2 to 0.6 L, 0.5 to 1.5 L, and 0.7 to 1.5 L. When the amount of solvent used is equal to or greater than the lower limit, the depolymerization of compound (4) proceeds more easily. When the amount of solvent used is equal to or less than the upper limit, excessive use of solvent is suppressed.

[0721] <Dehydrating Agent> In the depolymerization step of the depolymerization method (4), it is preferable to further use a dehydrating agent. In the depolymerization step, the presence of water makes it difficult for the depolymerization of compound (4) to proceed. That is, by using a dehydrating agent in the depolymerization step, the depolymerization of compound (4) proceeds more easily, and the yield of compound (41) is increased.

[0722] The dehydrating agent in the depolymerization method (4) is the same as the dehydrating agent in the depolymerization method (1).

[0723] The dehydrating agent used in the depolymerization step of the depolymerization method (4) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0724] The dehydrating agent used in the depolymerization step of the depolymerization method (4) is preferably one or more selected from the group consisting of sodium hydride, potassium hydride, calcium hydride, calcium oxide, cesium chloride, calcium chloride, magnesium sulfate, and zeolite.

[0725] In the case where a dehydrating agent is used in the depolymerization step of the depolymerization method (4), the amount of the dehydrating agent used is determined based on the repeating unit in the compound (4) (the symbol n in the general formula (4)). ４The molar amount of the dehydrating agent is preferably 2 to 8 times, for example, 2 to 6 times, or 2 to 4.5 times, the number of moles of the structural unit (the structural unit marked with "") (the structural unit marked with ""). When the amount of the dehydrating agent used is equal to or greater than the lower limit, the depolymerization of compound (4) is more likely to proceed. When the amount of the dehydrating agent used is equal to or less than the upper limit, excessive use of the dehydrating agent is suppressed.

[0726] <Other Components> In the depolymerization step of the depolymerization method (4), the compound (4) may be depolymerized using another component that does not fall into any of the compound (4), a hydroxide, optionally a solvent, and optionally a dehydrating agent, within a range that does not impair the effects of the present invention, or the compound (4) may be depolymerized without using the other component.

[0727] The other components in the depolymerization method (4) are the same as the other components in the depolymerization method (1).

[0728] The other component used in the depolymerization step of the depolymerization method (4) may be one kind or two or more kinds. When two or more kinds are used, the combination and ratio thereof can be arbitrarily selected depending on the purpose.

[0729] When depolymerizing compound (4) in the depolymerization step of depolymerization method (4), the ratio of the total amount (parts by mass) of the hydroxide, solvent, and dehydrating agent to the total amount (parts by mass) of the hydroxide, solvent, dehydrating agent, and other components (([amount (parts by mass) of hydroxide] + [amount (parts by mass) of solvent] + [amount (parts by mass) of dehydrating agent]) / ([amount (parts by mass) of hydroxide] + [amount (parts by mass) of solvent] + [amount (parts by mass) of dehydrating agent] + [amount (parts by mass) of other components]) × 100) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and may be, for example, any one of 97% by mass or more and 99% by mass or more. When this ratio is equal to or greater than the lower limit, the depolymerization of compound (4) proceeds more easily.

[0730] On the other hand, the proportion is 100% by mass or less.

[0731] When depolymerizing compound (4), if no optional component (i.e., a solvent, a dehydrating agent, or the other component) is used, the amount of the optional component used when calculating the above ratio is 0 part by mass.

[0732] <Other Conditions> In the depolymerization step of the depolymerization method (4), the compound (4), a hydroxide, and optionally a solvent, optionally a dehydrating agent, and optionally the other components are mixed, and the resulting mixture is heated and stirred, thereby depolymerizing the compound (4).

[0733] In the depolymerization step of the depolymerization method (4), the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (4) are the same as the temperature when the mixture is heated and stirred (reaction temperature), the time when the mixture is heated and stirred (reaction time), and the atmosphere during the depolymerization of compound (1), respectively.

[0734] In the depolymerization step of the depolymerization method (4), it is more preferable to carry out the depolymerization of compound (4) using a dehydrating agent under the inert gas atmosphere, it is more preferable to carry out the depolymerization of compound (4) using a hydroxide that has been dried by heating under reduced pressure under the inert gas atmosphere, and it is even more preferable to carry out the depolymerization of compound (4) using a dehydrating agent and a hydroxide that has been dried by heating under reduced pressure under the inert gas atmosphere. By doing so, the yield of the target product (compound (41)) can be further increased.

[0735] In the depolymerization method (4), after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (1), and the target substance (product) may be isolated, and the isolated target substance may be further purified, if necessary. Alternatively, after completion of the depolymerization step, the obtained reaction mixture may be post-treated, if necessary, in the same manner as in the depolymerization method (1), and then used for the next intended application without isolation of the target substance.

[0736] The structure of the product obtained by the depolymerization method (4) can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0737] ◎ Method for Producing Ether Compounds A method for producing an ether compound according to one embodiment of the present invention comprises depolymerizing one or more compounds selected from the group consisting of the compound represented by the general formula (11) (compound (11)) and a salt thereof, the compound represented by the general formula (121) (compound (121)) and a salt thereof, the compound represented by the general formula (122) (compound (122)) and a salt thereof, and the compound represented by the general formula (123) (compound (123)) and a salt thereof, one or more compounds selected from the group consisting of the compound represented by the general formula (21) (compound (21)) and a salt thereof, and the compound represented by the general formula (22) (compound (22)) and a salt thereof, or one or more compounds selected from the group consisting of the compound represented by the general formula (41) (compound (41)) and a salt thereof, which are obtained by the method for depolymerizing a compound according to one embodiment of the present invention described above. The method includes a step of etherifying one or more phenolic hydroxyl groups or groups in which the phenolic hydroxyl groups form salts to obtain an ether compound (sometimes referred to as an "etherification step" in this specification).

[0738] In this specification, the compound (11) obtained by the above-mentioned depolymerization method may be collectively referred to as "monomer".

[0739] According to the production method of this embodiment, the monomer, which is the product obtained by the depolymerization method (depolymerization method (1), depolymerization method (2), or depolymerization method (4)), can be easily etherified at its hydroxyl group or a group formed by forming a salt with the hydroxyl group. In particular, the monomer can be etherified without being isolated, because the depolymerization of compound (1), compound (2), or compound (4) in the depolymerization method proceeds cleanly with side reactions suppressed.

[0740] Among the monomers, a salt of compound (11), a salt of compound (121), a salt of compound (122), a salt of compound (123), a salt of compound (21), a salt of compound (22), and a salt of compound (41) are the target products of the depolymerization method (1), (2), or (4) described above.

[0741] The ether compound has a structure in which one or two hydrogen atoms (H) in the phenolic hydroxyl groups (-OH) of the monomer, or M in the group represented by the formula "-OM", are substituted with a monovalent hydrocarbon group. The group represented by the formula "-OM" is a group in which the phenolic hydroxyl group forms a salt.

[0742] The ether compound obtained from the compound (11) or a salt thereof includes a compound represented by the following general formula (110).

[0743] The ether compound obtained from the compound (121) or a salt thereof includes a compound represented by the following general formula (1210).

[0744] The ether compound obtained from the compound (122) or a salt thereof includes a compound represented by the following general formula (1220).

[0745] The ether compound obtained from the compound (123) or a salt thereof includes a compound represented by the following general formula (1230).

[0746] (In the formula, Z １１ , Z １２ , X １１ , X １２ , X ２１ , X ３１ , X ３２ , m １１ , m １２ , l １１ , l １２ , l ２１ , l ３１ and l ３２ is the same as above; R １１１ and R １１２ are each independently a hydrogen atom or a hydrocarbon group, provided that R １１１ and R １１２ are not both hydrogen atoms, and R１１１ or R １１２ is a hydrogen atom, the formula "-OR １１１ " or a group represented by the formula "-OR １１２ " may form a group represented by the formula "-OM"; R １２１ and R １２２ are each independently a hydrogen atom or a hydrocarbon group, provided that R １２１ and R １２２ are not both hydrogen atoms, and R １２１ or R １２２ is a hydrogen atom, the formula "-OR １２１ " or a group represented by the formula "-OR １２２ " may form a group represented by the formula "-OM"; R １３１ and R １３２ are each independently a hydrogen atom or a hydrocarbon group, provided that R １３１ and R １３２ are not both hydrogen atoms, and R １３１ or R １３２ is a hydrogen atom, the formula "-OR １３１ " or a group represented by the formula "-OR １３２ " may form a group represented by the formula "-OM"; R １４１ and R １４２ are each independently a hydrogen atom or a hydrocarbon group, provided that R １４１ and R １４２ are not both hydrogen atoms, and R １４１ or R １４２ is a hydrogen atom, the formula "-OR １４１ " or a group represented by the formula "-OR １４２ " may form a group represented by the formula "-OM".

[0747] In the compound represented by the general formula (110), R １１１ or R １１２ is a hydrogen atom, the formula "-OR １１１ " or a group represented by the formula "-OR １１２" forms a group represented by the formula "-OM" means that, when the compound represented by the general formula (110) has a hydroxyl group (-OH), this compound forms a salt at the hydroxyl group.

[0748] This also applies to the compound represented by the general formula (110), the compound represented by the general formula (1210), the compound represented by the general formula (1220), and the compound represented by the general formula (1230).

[0749] The ether compound obtained from the compound (21) or a salt thereof includes a compound represented by the following general formula (210).

[0750] The ether compound obtained from the compound (22) or a salt thereof includes a compound represented by the following general formula (220).

[0751] (In the formula, Z ２１ , Z ２２ , Z ２３ , m ２１ , m ２２ and m ２３ is the same as above; R ２１ and R ２２ are each independently a hydrogen atom or a hydrocarbon group, provided that R ２１ and R ２２ are not both hydrogen atoms, and R ２１ or R ２２ is a hydrogen atom, the formula "-OR ２１ " or a group represented by the formula "-OR ２２ " may form a group represented by the formula "-OM"; R ２３１ and R ２３２ are each independently a hydrogen atom or a hydrocarbon group, provided that R ２３１ and R ２３２ are not both hydrogen atoms, and R ２３１ or R ２３２ is a hydrogen atom, the formula "-OR ２３１ " or a group represented by the formula "-OR ２３２ " may form a group represented by the formula "-OM".

[0752] In the compound represented by the general formula (210), R ２１ or R ２２ is a hydrogen atom, the formula "-OR ２１ " or a group represented by the formula "-OR ２２ " forms a group represented by the formula "-OM" means that, when the compound represented by the general formula (210) has a hydroxyl group (-OH), this compound forms a salt at the hydroxyl group.

[0753] This also applies to the compound represented by the general formula (220).

[0754] The ether compound obtained from the compound (41) or a salt thereof includes a compound represented by the following general formula (410). (In the formula, Z ４１ , Z ４２ , m ４１ and m ４２ is the same as above; R ４１ and R ４２ are each independently a hydrogen atom or a hydrocarbon group, provided that R ４１ and R ４２ are not both hydrogen atoms, ４１ or R ４２ is a hydrogen atom, the formula "-OR ４１ " or a group represented by the formula "-OR ４２ " may form a group represented by the formula "-OM".

[0755] In the compound represented by the general formula (410), R ４１ or R ４２ is a hydrogen atom, the formula "-OR ４１ " or a group represented by the formula "-OR ４２ " forms a group represented by the formula "-OM" means that, when the compound represented by the general formula (410) has a hydroxyl group (-OH), this compound forms a salt at the hydroxyl group.

[0756] The hydrocarbon group (R １１１ , R １１２ , R１２１ , R １２２ , R １３１ , R １３２ , R １４１ , R １４２ , R ２１ , R ２２ , R ２３１ , R ２３２ , R ４１ and R ４２ Examples of the hydrocarbon group include an alkyl group and an aralkyl group (also known as an arylalkyl group).

[0757] The alkyl group in which a hydrogen atom is substituted includes Z １１ and Z １２ Examples of the alkyl group substituted with a hydrogen atom include the same as the alkyl group in (1). The alkyl group substituted with a hydrogen atom may be linear, branched, or cyclic, and may have both a chain structure (linear or branched) and a cyclic structure. The cyclic structure in the cyclic alkyl group (an alkyl group having a cyclic structure but not a chain structure, and an alkyl group having both a cyclic structure and a chain structure) may be monocyclic or polycyclic.

[0758] The alkyl group with which the hydrogen atom is substituted is preferably an alkyl group having 1 to 15 carbon atoms (a linear alkyl group having 1 to 15 carbon atoms or a cyclic alkyl group having 3 to 15 carbon atoms), and may be, for example, any one of an alkyl group having 1 to 10 carbon atoms (a linear alkyl group having 1 to 10 carbon atoms or a cyclic alkyl group having 3 to 10 carbon atoms), an alkyl group having 1 to 8 carbon atoms (a linear alkyl group having 1 to 8 carbon atoms or a cyclic alkyl group having 3 to 8 carbon atoms), an alkyl group having 1 to 6 carbon atoms (a linear alkyl group having 1 to 6 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms), and an alkyl group having 1 to 3 carbon atoms.

[0759] Examples of the aralkyl group in which a hydrogen atom is substituted include the above-mentioned Z １１ and Z １２ and a monovalent group having a structure in which one hydrogen atom bonded to a carbon atom having no free valence in the alkyl group is substituted with an aryl group.

[0760] The aryl group may be either monocyclic or polycyclic.

[0761] The number of carbon atoms in the aryl group is preferably 6 to 15. Examples of the aryl group include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, and a xylyl group (dimethylphenyl group). Furthermore, one or more hydrogen atoms in these aryl groups may be substituted with a phenyl group or a xylyl group (dimethylphenyl group). １１ and Z １２ The aryl group having such a substituent preferably has 6 to 15 carbon atoms.

[0762] The aryl group more preferably has 6 to 12 carbon atoms.

[0763] The number of carbon atoms in the aralkyl group where a hydrogen atom is substituted is preferably 7 to 17. Examples of the aralkyl group include a benzyl group (phenylmethyl group), a phenethyl group (phenylethyl group), a 1-naphthylmethyl group, a 2-naphthylmethyl group, an o-tolylmethyl group, an m-tolylmethyl group, a p-tolylmethyl group, and a xylylmethyl group.

[0764] The aralkyl group more preferably has 7 to 14 carbon atoms.

[0765] In the etherification step, one or more (more specifically, one or two) phenolic hydroxyl groups or groups in which a phenolic hydroxyl group forms a salt in the monomer can be etherified by reacting the monomer with an etherifying agent capable of substituting a hydrogen atom in a hydroxyl group or M in the group represented by the formula "-OM" with the hydrocarbon group.

[0766] The etherifying agent may be a known agent.

[0767] When the etherification is alkyl etherification, examples of the etherification agent include alkyl halides and acid alkyl esters.

[0768] Examples of the alkyl halide include methyl iodide (CH３ alkyl iodides such as (bromomethyl)cyclopropane (c-(C ３ H ５ ) CH ２ Br), 1-bromo-3,7-dimethyloctane (CH ３ CH (CH ３ ) CH ２ CH ２ CH ２ CH (CH ３ ) CH ２ CH ２ Br) and the like.

[0769] Examples of the acid alkyl ester include methyl trifluoromethanesulfonate (CF ３ SO ３ CH ３ ), dimethyl sulfate ((CH ３ ) ２ SO ４ ) etc.

[0770] When the etherification is aralkyl etherification, the etherification agent may be, for example, benzyl bromide (C ６ H ５ CH ２ Br), and the like (for example, aralkyl bromide).

[0771] When the ether compound is a compound in which two phenolic hydroxyl groups or groups in which phenolic hydroxyl groups form salts in the monomer are etherified, the amount of the etherifying agent used in the etherification step is preferably 2 to 5 times the molar amount of the monomer, and may be, for example, 2 to 4 times or 2 to 3 times the molar amount of the monomer, regardless of the type of the monomer. When the amount of the etherifying agent used is equal to or greater than the lower limit, the yield of the target ether compound is increased. When the amount of the etherifying agent used is equal to or less than the upper limit, excessive use of the etherifying agent is suppressed.

[0772] When the ether compound is a compound in which one phenolic hydroxyl group or a group in which a phenolic hydroxyl group has formed a salt in the monomer has been etherified, the amount of the etherifying agent used in the etherification step is preferably 1 to 2.5 times the molar amount of the monomer, regardless of the type of the monomer, and may be, for example, 1 to 2 times or 1 to 1.5 times the molar amount of the monomer. When the amount of the etherifying agent used is equal to or greater than the lower limit, the yield of the target ether compound is increased. When the amount of the etherifying agent used is equal to or less than the upper limit, excessive use of the etherifying agent is suppressed.

[0773] In the case where the etherification step is carried out without taking out the monomer obtained by the depolymerization method (1), the monomer is one or more selected from the group consisting of compound (11) and a salt thereof, compound (121) and a salt thereof, compound (122) and a salt thereof, and compound (123) and a salt thereof, and the ether compound is a compound in which two phenolic hydroxyl groups or groups in which phenolic hydroxyl groups have formed salts in the monomer have been etherified, the amount of the etherification agent used in the etherification step is set to be equal to or less than the amount of the repeating unit in compound (1) (symbol n in general formula (1)). １ The amount of the etherifying agent used may be, for example, 4 to 10 times, 4 to 8 times, or 4 to 6 times the number of moles of the etherifying agent (structural unit marked with "") (the etherifying agent is a structural unit marked with "."). When the amount of the etherifying agent used is equal to or greater than the lower limit, the yield of the target ether compound is increased. When the amount of the etherifying agent used is equal to or less than the upper limit, excessive use of the etherifying agent is suppressed.

[0774] When the ether compound is a compound in which one phenolic hydroxyl group or a group in which a phenolic hydroxyl group has formed a salt in the monomer has been etherified, the amount of the etherifying agent used may be, for example, 2 to 5 times, 2 to 4 times, or 2 to 3 times the molar amount of the repeating unit in compound (1), for the same reason as above.

[0775] The same applies when the depolymerization method (2) is adopted.

[0776] That is, in the case where the etherification step is carried out without taking out the monomer obtained by the depolymerization method (2), the monomer is one or more selected from the group consisting of compound (21) and a salt thereof, and compound (22) and a salt thereof, and the ether compound is a compound in which two phenolic hydroxyl groups or groups in which phenolic hydroxyl groups have formed salts in the monomer are etherified, the amount of the etherification agent used in the etherification step is set to be equal to or less than the amount of the repeating unit in compound (2) (symbol n in general formula (2)). ２ The amount of the etherifying agent used may be, for example, 4 to 10 times, 4 to 8 times, or 4 to 6 times the number of moles of the etherifying agent (structural unit marked with "") (the etherifying agent is a structural unit marked with "."). When the amount of the etherifying agent used is equal to or greater than the lower limit, the yield of the target ether compound is increased. When the amount of the etherifying agent used is equal to or less than the upper limit, excessive use of the etherifying agent is suppressed.

[0777] When the ether compound is a compound in which one phenolic hydroxyl group or a group in which a phenolic hydroxyl group has formed a salt in the monomer has been etherified, the amount of the etherifying agent used may be, for example, 2 to 5 times, 2 to 4 times, or 2 to 3 times the molar amount of the repeating unit in compound (2), for the same reason as above.

[0778] As will be described later, in the case where the etherification step is carried out without taking out the monomer obtained by the depolymerization method (4), the monomer is one or more selected from the group consisting of compound (41) and salts thereof, and the ether compound is a compound in which two phenolic hydroxyl groups or groups in which phenolic hydroxyl groups have formed salts in the monomer are etherified, the amount of the etherification agent used in the etherification step is determined based on the repeating unit in compound (4) (symbol n in general formula (4)). ４The amount of the etherifying agent used may be, for example, 2 to 5 times, 2 to 4 times, or 2 to 3 times the number of moles of the etherifying agent (structural unit marked with "") (the unit marked with ""). When the amount of the etherifying agent used is equal to or greater than the lower limit, the yield of the target ether compound is increased. When the amount of the etherifying agent used is equal to or less than the upper limit, excessive use of the etherifying agent is suppressed.

[0779] When the ether compound is a compound in which one phenolic hydroxyl group or a group in which a phenolic hydroxyl group has formed a salt in the monomer has been etherified, the amount of the etherifying agent used may be, for example, 1 to 2.5 times, 1 to 2 times, or 1 to 1.5 times the molar amount of the repeating unit in compound (4), for the same reason as above.

[0780] The etherification in the etherification step is preferably carried out using a solvent.

[0781] Examples of the solvent include the same solvents as those used in the depolymerization step in the depolymerization method (1), (2), or (4).

[0782] When the etherification step is carried out without taking out the monomer obtained by the depolymerization method (1), (2), or (4), after completion of the depolymerization step in the depolymerization method (1), (2), or (4), if necessary, the reaction mixture obtained may be post-treated as described above, and the resulting solution may be used as it is to etherify the monomer.

[0783] In the production method, after the etherification step is completed, the resulting reaction mixture can be post-treated as needed by known techniques to isolate the target product (ether compound). That is, post-treatment procedures such as filtration, washing, extraction, pH adjustment, dehydration, and concentration can be performed, either alone or in combination, as needed, and the target product can be isolated by concentration, crystallization, reprecipitation, column chromatography, or the like. The isolated target product can also be purified by performing, as needed, crystallization, reprecipitation, column chromatography, extraction, stirring and washing of crystals with a solvent, either alone or in combination, once or more times. Alternatively, after the etherification step is completed, the resulting reaction mixture can be post-treated as needed, and then used for the next intended application without isolating the target product. For example, the target product can be subjected to the next intended reaction without being isolated.

[0784] The structure of the product obtained by the above-described production method can be confirmed by known techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS), and infrared spectroscopy (IR).

[0785] The present invention will be described in more detail below with reference to specific examples, although the present invention is not limited to the examples shown below.

[0786] <<Depolymerization of Polysulfone (Depolymerization Method (1))>>

[0787] Example 1 Under an argon atmosphere, sodium hydroxide (NaOH) (0.8 mmol, a four-fold molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.4 mL) were sequentially added to pellet-shaped polysulfone (89.2 mg; an amount corresponding to 0.20 mmol of the repeating unit in general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302), and the mixture was heated to 150°C to dissolve the polysulfone. The mixture was then stirred at 150°C for 18 hours. The sodium hydroxide was previously dried by heating at 150°C for 5 hours under reduced pressure (266.644 Pa (2 mmHg)).

[0788] The temperature of the resulting reaction mixture was then returned to room temperature, and 1 M hydrochloric acid (1.0 mL) was added and stirred. Then, mesitylene (5.0 μL, 0.036 mmol) and deuterated chloroform (CDCl ３ ) (0.5 mL) was added and the organic layer was removed. １ By analyzing with H NMR, it was confirmed that the target products (depolymerization products), bisphenol S (BPS, corresponding to compound (11)) and bisphenol A (BPA, corresponding to compound (121)), were obtained, and the yields of these target products and the intermediate products, compound (A) represented by the following formula (A) and compound (B) represented by the following formula (B), were calculated. The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0789] Example 2 Under an argon atmosphere, potassium hydroxide (KOH) (2.0 mmol, a four-fold molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (1.0 mL) were sequentially added to pellet-shaped polysulfone (222 mg; an amount corresponding to 0.50 mmol of the repeating unit in general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302), and the mixture was heated to 150°C to dissolve the polysulfone. The mixture was then stirred at 150°C for 20 hours. The potassium hydroxide was previously dried by heating at 150°C for 5 hours under reduced pressure (266.644 Pa (2 mmHg)).

[0790] The temperature of the resulting reaction mixture was then returned to room temperature, and 2 M hydrochloric acid (1.0 mL) and N,N-dimethylformamide (10 μL, 0.13 mmol) were added. A small amount of the solution was taken out and diluted with deuterated acetone ((CD ３ ) ２ CO) (0.50 mL), １ The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0791] [Example 3] Instead of potassium hydroxide (2.0 mmol), cesium hydroxide monohydrate (CsOH·H ２ Depolymerization of polysulfone was carried out in the same manner as in Example 2, except that cesium hydroxide monohydrate (2.0 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) was used. The cesium hydroxide monohydrate was previously dried by heating at 150°C for 5 hours under reduced pressure (266.644 Pa (2 mmHg)) before use. The polysulfone was dissolved during depolymerization.

[0792] The reaction mixture was analyzed in the same manner as in Example 2, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. The yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0793] Example 4 Depolymerization of polysulfone was carried out in the same manner as in Example 3, except that the reaction temperature was changed to 120°C instead of 150°C and the reaction time was changed to 18 hours instead of 20 hours. During depolymerization, the polysulfone was dissolved.

[0794] The reaction mixture was analyzed in the same manner as in Example 2, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. The yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0795] Example 5 Depolymerization of polysulfone was carried out in the same manner as in Example 1, except that the amount of sodium hydroxide used was changed from 0.8 mmol to 1.2 mmol (6 times the molar amount (6 equivalents) relative to the repeating unit in general formula (1)). During depolymerization, polysulfone was dissolved.

[0796] The resulting reaction mixture was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. Furthermore, the yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0797] [Example 6] Depolymerization of polysulfone was carried out in the same manner as in Example 5, except that potassium hydroxide (1.2 mmol) was used instead of sodium hydroxide (1.2 mmol) and the reaction time was changed from 18 hours to 19 hours. During depolymerization, polysulfone was dissolved.

[0798] The resulting reaction mixture was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. Furthermore, the yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0799] Example 7 Depolymerization of polysulfone was carried out in the same manner as in Example 3, except that the amount of cesium hydroxide monohydrate used was changed from 2.0 mmol to 3.0 mmol (6 times the molar amount (6 equivalents) relative to the repeating unit in general formula (1)). During depolymerization, the polysulfone was dissolved.

[0800] The resulting reaction mixture was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. Furthermore, the yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 1. １ The results of the H NMR analysis are shown in FIG.

[0801] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0802] As is clear from the above results, it was confirmed that bisphenol S and bisphenol A could be obtained in good yields even when the type of hydroxide was changed. In particular, when cesium hydroxide monohydrate was used as the hydroxide, the yields of bisphenol S and bisphenol A were particularly high.

[0803] From a comparison between Examples 1 to 3 and Examples 5 to 7, it was confirmed that the yield of bisphenol S and bisphenol A tends to increase by increasing the amount of hydroxide used.

[0804] From a comparison between Example 3 and Example 4, it was confirmed that the yields of bisphenol S and bisphenol A increased by increasing the reaction temperature.

[0805] Depolymerization of polysulfone was carried out in the same manner as in Example 3, except that cesium hydroxide monohydrate that had not been subjected to heat drying under reduced pressure at 150°C for 5 hours was used instead. As a result, the yields of bisphenol S (BPS) and bisphenol A (BPA) were lower than in Example 3. This result specifically confirmed that depolymerization of compound (1) is preferably carried out under dehydrating conditions.

[0806] <<Depolymerization of Polysulfone (Depolymerization Method (1))>> [Example 8] Under an argon atmosphere, pellet-shaped polysulfone (44.3 mg; an amount corresponding to 0.10 mmol of the repeating unit in the general formula (1); weight average molecular weight: 35,000; number average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was depolymerized with calcium hydride (CaH ２ , dehydrating agent) (0.4 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in the general formula (1)) and cesium hydroxide monohydrate (CsOH.H ２ To the mixture were added 0.4 mmol of 1,3-dimethyl-2-imidazolidinone (DMI) (4 equivalents, 4 times the molar amount relative to the repeating unit in general formula (1)) and 0.2 mL of 1,3-dimethyl-2-imidazolidinone (DMI), and the resulting mixture was heated at 150°C to dissolve the polysulfone. The mixture was then stirred at 150°C for 18 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0807] The reaction mixture was then returned to room temperature, 1 M hydrochloric acid (1.0 mL) and ethyl acetate were added, and the organic layer was washed successively with water and a saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0808] The obtained crude product was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. Furthermore, the yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 2. １ The results of the H NMR analysis are shown in FIG.

[0809] Example 9 Depolymerization of polysulfone was carried out in the same manner as in Example 8, except that the amount of calcium hydride used was changed from 0.4 mmol to 0.2 mmol (twice the molar amount (2 equivalents) relative to the repeating unit in general formula (1)). During depolymerization, polysulfone was dissolved.

[0810] The obtained crude product was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. Furthermore, the yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 2. １ The results of the H NMR analysis are shown in FIG.

[0811] Example 10 Depolymerization of polysulfone was carried out in the same manner as in Example 8, except that calcium oxide (CaO) (0.4 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) was used instead of calcium hydride (0.4 mmol). During depolymerization, polysulfone was dissolved.

[0812] The obtained crude product was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. Furthermore, the yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 2. １ The results of the H NMR analysis are shown in FIG.

[0813] Example 11 Under an argon atmosphere, pellet-shaped polysulfone (45.6 mg; the amount corresponding to 0.10 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was dissolved in cesium hydroxide monohydrate (CsOH·H ２ O) (0.4 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in the general formula (1)) and cesium chloride (CsCl ２ ) (0.3 mmol, 3 times the molar amount (3 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.2 mL) were added sequentially, and the mixture was heated to 150°C to dissolve the polysulfone. The resulting mixture was then stirred at 150°C for 20 hours. Cesium hydroxide monohydrate and cesium chloride were previously dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0814] The reaction mixture was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. The yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 2. １ The results of the H NMR analysis are shown in FIG.

[0815] Example 12 Depolymerization of polysulfone was carried out in the same manner as in Example 11, except that zeolite (Molecular Sieve 4A manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (3 grains) was used instead of cesium chloride (0.3 mmol) and the reaction time was changed from 20 hours to 18 hours. During depolymerization, polysulfone was dissolved.

[0816] The reaction mixture was analyzed in the same manner as in Example 1, and it was confirmed that bisphenol S (BPS) and bisphenol A (BPA) were obtained. The yields of these target products, compound (A), and compound (B) were calculated. The results are shown in Table 2. １ The results of the H NMR analysis are shown in FIG.

[0817] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0818]

[0819] Comparison of Example 3 with Examples 8 and 9 confirmed that depolymerization proceeded more efficiently by using calcium hydride as a dehydrating agent. Compound (B) was not detected in Examples 8 and 9.

[0820] In Examples 10 to 12, the use of a dehydrating agent reduced the yields of bisphenol S and bisphenol A, which was presumably due to the dehydrating agent reacting or interacting with some of the hydroxides.

[0821] From a comparison between Example 8 and Example 9, it was confirmed that the yields of bisphenol S and bisphenol A increased by increasing the amount of the dehydrating agent used.

[0822] <<Depolymerization of Polysulfone on a Gram Scale (Depolymerization Method (1) for Scale-Up)>>

[0823] Example 13 Under an argon atmosphere, pellet-shaped polysulfone (2.21 g; the amount corresponding to 5.0 mmol of the repeating unit in the general formula (1); weight-average molecular weight: 35,000; number-average molecular weight: 16,000; manufactured by Sigma-Aldrich, Cat. No. 428302) was mixed with cesium hydroxide monohydrate (CsOH·H ２ O) (20 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and calcium hydride (CaH ２ ) (20 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (10 mL) were added sequentially, and the resulting mixture was heated at 150°C to dissolve the polysulfone. The mixture was then stirred at 150°C for 18 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0824] Next, the temperature of the resulting reaction mixture was returned to room temperature, and 0.5 M hydrochloric acid (20 mL) and ethyl acetate (30 mL) were added and stirred. Then, filtration was performed using Celite (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and ethyl acetate (30 mL) and water (30 mL) were added and stirred to separate the organic layer and the aqueous layer. The organic layer was washed with water (50 mL x 3), and the resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain crude product (C1).

[0825] Next, 2 M hydrochloric acid (10 mL) was added to the aqueous layer obtained above, and the organic layer was extracted with ethyl acetate (50 mL) and washed with water (50 mL × 3). The obtained organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product (C2).

[0826] Next, the crude product (C1) was recrystallized using acetone to isolate bisphenol A (BPA) (yield: 532 mg, 47%). Meanwhile, the crude product (C2) was purified by silica gel column chromatography to isolate bisphenol S (BPS) (yield: 897 mg, 72%) and bisphenol A (BPA) (yield: 127 mg, 11%). １ The results of the H NMR analysis are shown in FIG. １ The results of the H NMR analysis are shown in FIG.

[0827] <<Depolymerization of Polysulfone (Depolymerization Method (1)), Production of Ether Compound>> [Example 14] <Depolymerization of Polysulfone> Under an argon atmosphere, calcium hydride (CaH ２ , dehydrating agent) (50.5 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in the general formula (1)) and cesium hydroxide monohydrate (CsOH.H ２ O) (201 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) were added sequentially, and the resulting mixture was heated at 150°C to dissolve the polysulfone. Thereafter, the mixture was stirred at 150°C for 19 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use. <Production of Ether Compound> Next, the temperature of the reaction mixture obtained above was returned to room temperature, and benzyl bromide (C ６ H ５ CH ２Br) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) was added, and the mixture was stirred at 100°C for 3 hours. The temperature of the resulting reaction mixture was returned to room temperature, and 1 M hydrochloric acid (1.0 mL) and ethyl acetate (2.0 mL) were added sequentially, and the organic layer was washed sequentially with water and a saturated aqueous sodium chloride solution. The resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0828] To the obtained crude product was added mesitylene (5.0 μL, 0.036 mmol), and １ H NMR analysis confirmed that the target products (ether compounds), bisphenol S dibenzyl ether (corresponding to compound (110)) and bisphenol A dibenzyl ether (corresponding to compound (1210)), were obtained. Furthermore, the yields of these target products were calculated to be 92% for bisphenol S dibenzyl ether and 89% for bisphenol A dibenzyl ether. １ The results of the H NMR analysis are shown in FIG.

[0829] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0830] <<Depolymerization of Polysulfone (Depolymerization Method (1)), Production of Ether Compound>> [Example 15] <Depolymerization of Polysulfone> Under an argon atmosphere, calcium hydride (CaH ２ , dehydrating agent) (50.5 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in the general formula (1)) and cesium hydroxide monohydrate (CsOH.H ２O) (201 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) were added sequentially, and the resulting mixture was heated at 150°C to dissolve the polysulfone. This was followed by stirring at 150°C for 19 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use. <Production of Ether Compound> Next, the temperature of the reaction mixture obtained above was returned to room temperature, and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) and (bromomethyl)cyclopropane (c-(C ３ H ５ ) CH ２ Br) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) was added, and the mixture was stirred at 100° C. for 3 hours.

[0831] The temperature of the resulting reaction mixture was returned to room temperature, and mesitylene (5.0 μL, 0.036 mmol) and deuterated chloroform (CDCl ３ ) (0.5 mL) was added and the organic layer was removed. １ H NMR analysis confirmed that the target products (ether compounds), bisphenol S di(cyclopropylmethyl) ether (corresponding to compound (110)) and bisphenol A di(cyclopropylmethyl) ether (corresponding to compound (1210)), were obtained. Furthermore, the yields of these target products were calculated to be 71% for bisphenol S di(cyclopropylmethyl) ether and 56% for bisphenol A di(cyclopropylmethyl) ether. １ The results of the H NMR analysis are shown in FIG.

[0832] (In the formula, n １０１ is an integer (preferably 10 to 200).

[0833] <<Depolymerization of Polysulfone (Depolymerization Method (1)), Production of Ether Compound>> [Example 16] <Depolymerization of Polysulfone> Under an argon atmosphere, calcium hydride (CaH ２ , dehydrating agent) (50.7 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in the general formula (1)) and cesium hydroxide monohydrate (CsOH.H ２ To the mixture were added 201 mg, 1.2 mmol, a 4-fold molar amount (4 equivalents) relative to the repeating unit in general formula (1), and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL), and the resulting mixture was heated at 150°C to dissolve the polysulfone. The mixture was then stirred at 150°C for 19 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0834] <Production of Ether Compound> Next, the temperature of the reaction mixture obtained above was returned to room temperature, and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) and 1-bromo-3,7-dimethyloctane (CH ３ CH (CH ３ ) CH ２ CH ２ CH ２ CH (CH ３ ) CH ２ CH ２ Br) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) was added, and the mixture was stirred at 100° C. for 3 hours.

[0835] The temperature of the resulting reaction mixture was returned to room temperature, and mesitylene (5.0 μL, 0.036 mmol) and deuterated chloroform (CDCl ３ ) (0.5 mL) was added and the organic layer was removed. １H NMR analysis confirmed that the target products (ether compounds), bisphenol S di(3,7-dimethyloctyl) ether (corresponding to compound (110)) and bisphenol A di(3,7-dimethyloctyl) ether (corresponding to compound (1210)), were obtained. Furthermore, when the yields of these target products were calculated, the yield of bisphenol S di(3,7-dimethyloctyl) ether was 92%, and the yield of bisphenol A di(3,7-dimethyloctyl) ether was 89%. １ The results of the H NMR analysis are shown in FIG.

[0836] (In the formula, n １０１ is an integer (preferably 10 to 200).) As is clear from the results of Examples 14 to 16, the target ether compound was easily obtained by allowing an etherifying agent (here, an alkyl halide or an aralkyl halide) to act on the product (monomer) of depolymerization of polysulfone. Furthermore, even when the type of etherifying agent was changed, the ether compound was obtained in good yield.

[0837] <<Depolymerization of Polyethersulfone (Depolymerization Method (4))>> [Example 17] Under an argon atmosphere, cesium hydroxide monohydrate (CsOH.H ２ To the mixture were added 1,3-dimethyl-2-imidazolidinone (DMI) (51.2 mg, 0.3 mmol, 3 times the molar amount (3 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.2 mL), and the resulting mixture was heated at 150°C to dissolve the polyphenylsulfone. The mixture was then stirred at 150°C for 19 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0838] Next, the temperature of the resulting reaction mixture was returned to room temperature, and 1 M hydrochloric acid (2.0 mL) and methylene chloride (3 mL) were added to extract the organic layer. Thereafter, the organic layer was washed successively with water and a saturated aqueous sodium chloride solution. The resulting organic layer was dried over anhydrous magnesium sulfate, and the precipitated solid was washed with hexane and evaporated under reduced pressure to obtain the target product, bisphenol S (BPS) (corresponding to compound (41)) (yield: 20.7 mg, 83%). １ The results of the H NMR analysis are shown in FIG.

[0839] (In the formula, n ４０１ is an integer (preferably 10 to 200).

[0840] <<Depolymerization of Polyethersulfone (Depolymerization Method (4)), Production of Ether Compound>> [Example 18] <Depolymerization of Polyethersulfone> Cesium hydroxide monohydrate (CsOH.H ２ To the mixture were added 1,3-dimethyl-2-imidazolidinone (DMI) (50.4 mg, 0.3 mmol, 3 times the molar amount (3 equivalents) relative to the repeating unit in general formula (4)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.2 mL), and the resulting mixture was heated at 150°C to dissolve the polyethersulfone. The mixture was then stirred at 150°C for 19 hours. Cesium hydroxide monohydrate was dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0841] <Production of Ether Compound> Next, the temperature of the reaction mixture obtained was returned to room temperature, and benzyl bromide (C ６ H ５ CH ２ Br) (0.3 mmol, 3 times the molar amount (3 equivalents) relative to the repeating unit in general formula (4)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.2 mL) were added, and the mixture was stirred at 100°C for 2 hours.

[0842] The temperature of the resulting reaction mixture was returned to room temperature, water (1.0 mL) and methylene chloride (2.0 mL) were added successively, and the organic layer was washed successively with water and a saturated aqueous solution of sodium chloride. The resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0843] The obtained crude product was purified by silica gel column chromatography to isolate bisphenol S dibenzyl ether (corresponding to compound (410)) (yield: 38.4 mg, 87%). １ The results of the H NMR analysis are shown in FIG.

[0844] (In the formula, n ４０１ is an integer (preferably 10 to 200).

[0845] <<Depolymerization of Polyphenylsulfone (Depolymerization Method (1))>> [Example 19] Under an argon atmosphere, powdered polyphenylsulfone (120 mg; an amount corresponding to 0.3 mmol of the repeating unit in the general formula (1); manufactured by Standard-Testpiece, Cat. No. RMOLDED0050) was depolymerized with cesium hydroxide monohydrate (CsOH.H ２ 0) (202 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and calcium hydride (CaH ２ , dehydrating agent) (50.7 mg, 1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) were added sequentially, and the resulting mixture was heated at 150°C to dissolve the polyphenylsulfone. Thereafter, the mixture was stirred at 150°C for 19 hours. Cesium hydroxide monohydrate was previously dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0846] The temperature of the resulting reaction mixture was then returned to room temperature, and 1 M hydrochloric acid (3.6 mL) was added. Water (10 mL) and ethyl acetate (20 mL) were then added successively to extract the organic layer. The organic layer was then washed successively with water and a saturated aqueous sodium chloride solution. The resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0847] The obtained crude product was purified by silica gel column chromatography to isolate bisphenol S (corresponding to compound (110)) (yield: 65.2 mg, 87%) and 4,4'-dihydroxybiphenyl (corresponding to compound (123)) (yield: 44.7 mg, 80%). １ The results of the H NMR analysis are shown in FIG. 20. １ The results of the H NMR analysis are shown in FIG.

[0848] (In the formula, n １０２ is an integer (preferably 10 to 200).

[0849] <<Depolymerization of Polyether Ether Sulfone (Depolymerization Method (1))>> [Example 20] Under an argon atmosphere, cesium hydroxide monohydrate (CsOH.H ２ O) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and calcium hydride (CaH ２ ) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) were added sequentially, and the resulting mixture was heated at 150°C for 18 hours to dissolve the polyether ether sulfone. Thereafter, the mixture was stirred at 150°C for 22 hours. Cesium hydroxide monohydrate was previously dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0850] Next, the temperature of the resulting reaction mixture was returned to room temperature, and 2 M hydrochloric acid (1 mL) was added thereto. Further, N,N-dimethylformamide (DMF) (5.0 μL, 0.065 mmol) was added thereto, and １ H NMR analysis confirmed that the target products, bisphenol S (corresponding to compound (11)) and hydroquinone (corresponding to compound (122)), were obtained. Furthermore, the yields of these target products were calculated, and the yield of bisphenol S was 75% and the yield of hydroquinone was 68%.

[0851] Next, ethyl acetate (5 mL) and water (5 mL) were added to the reaction mixture obtained above, and the mixture was stirred, and the organic layer was extracted. The obtained organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0852] The obtained crude product was purified by silica gel column chromatography to isolate bisphenol S (BPS) (yield: 40.6 mg, 55%). １ The results of the H NMR analysis are shown in FIG.

[0853] (In the formula, n １０３ is an integer (preferably 10 to 200).

[0854] <<Depolymerization of Polyether Ether Ketone (Depolymerization Method (2))>> [Example 21] Under an argon atmosphere, cesium hydroxide monohydrate (CsOH.H ２ O) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (2)) and calcium hydride (CaH ２) (1.2 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (2)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.6 mL) were added sequentially, and the resulting mixture was heated at 150°C for 18 hours to dissolve the polyether ether ketone. Thereafter, the mixture was stirred at 150°C for 22 hours. Cesium hydroxide monohydrate was previously dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0855] The temperature of the resulting reaction mixture was then returned to room temperature, and 2 M hydrochloric acid (1 mL) was added. Ethyl acetate (5 mL) and water (5 mL) were then added and stirred, and the organic layer was extracted. The resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0856] The obtained crude product １ Analysis by H NMR confirmed that the target product, 4,4'-dihydroxybenzophenone (corresponding to compound (21)) was obtained (yield: 53%). This crude product was contaminated with the other target product, hydroquinone (corresponding to compound (22)) (yield: approximately 5%). １ The results of the H NMR analysis are shown in FIG.

[0857] (In the formula, n ２０１ is an integer (preferably 10 to 200).

[0858] <<Depolymerization of Polyphenylsulfone (Depolymerization Method (1))>> [Example 22] Under an argon atmosphere, a plate of polyphenylsulfone (45 mg; an amount corresponding to 0.1 mmol of the repeating unit in General Formula (1); a PPSU baby bottle manufactured by ChuChu Co.) was prepared by cutting a PPSU baby bottle into small pieces. Cesium hydroxide monohydrate (CsOH.H ２ 0) (68 mg, 0.4 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and calcium hydride (CaH ２, dehydrating agent) (18 mg, 0.4 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (0.2 mL) were added sequentially, and the resulting mixture was heated at 150°C to dissolve the polyphenylsulfone. Thereafter, the mixture was stirred at 150°C for 24 hours. Cesium hydroxide monohydrate was used after drying by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours.

[0859] The temperature of the resulting reaction mixture was then returned to room temperature, and 1 M hydrochloric acid (3.6 mL) was added. Water (2 mL) and ethyl acetate (5 mL) were then added successively to extract the organic layer. The organic layer was then washed successively with water and a saturated aqueous sodium chloride solution. The resulting organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0860] The obtained crude product was purified by thin layer chromatography to isolate bisphenol S (corresponding to compound (110)) (yield: 15.9 mg, 64%) and 4,4'-dihydroxybiphenyl (corresponding to compound (123)) (yield: 14.3 mg, 77%). １ The results of the H NMR analysis were the same as in Example 19.

[0861] (In the formula, n １０２ is an integer (preferably 10 to 200).

[0862] <<Depolymerization of Polyether Ether Sulfone (Depolymerization Method (5))>> [Example 22] Under an argon atmosphere, cesium hydroxide monohydrate (CsOH.H ２ 0) (704 mg; 12.6 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and calcium hydride (CaH ２) (513 mg; 12 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (1)) and 1,3-dimethyl-2-imidazolidinone (DMI) (6.0 mL) were added sequentially, and the mixture was stirred at 150°C for 20 hours. Cesium hydroxide monohydrate was previously dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0863] Next, the temperature of the resulting reaction mixture was returned to room temperature, and 2 M hydrochloric acid (15 mL) was added thereto. Further, N,N-dimethylformamide (DMF) (5.0 μL, 0.065 mmol) was added thereto, and １ H NMR analysis confirmed that the target products, bisphenol S (corresponding to compound (11)), hydroquinone (corresponding to compound (122)), and 4-((4-(4-hydroxyphenoxy)phenyl)sulfonyl)phenol (BPS-HQ), were obtained.

[0864] Next, ethyl acetate (50 mL) and water (50 mL) were added to the reaction mixture obtained above, and the mixture was stirred, and the organic layer was extracted. The obtained organic layer was dried over anhydrous magnesium sulfate and then evaporated under reduced pressure to obtain a crude product.

[0865] The obtained crude product was purified by silica gel column chromatography to isolate bisphenol S (BPS) (yield: 111 mg, 14%) and 4-((4-(4-Hydroxyphenoxy)phenyl)sulfonyl)phenol (BPS-HQ) (yield: 822 mg, 79%). １ The results of the H NMR analysis were the same as in Example 20. １ The results of the H NMR analysis are shown in FIG.

[0866] (In the formula, n １０３ is an integer (preferably 10 to 200).

[0867] <<Depolymerization of Polyether Ether Ketone (Depolymerization Method (6))>> [Example 23] Under an argon atmosphere, cesium hydroxide monohydrate (CsOH.H ２ Cesium hydroxide monohydrate (335 mg; 2.0 mmol, 4 times the molar amount (4 equivalents) relative to the repeating unit in general formula (2)) and 1,3-dimethyl-2-imidazolidinone (DMI) (1.0 mL) were added sequentially, and the resulting mixture was stirred at 150°C for 19 hours. Cesium hydroxide monohydrate was previously dried by heating under reduced pressure (266.644 Pa (2 mmHg)) at 150°C for 5 hours before use.

[0868] Next, the temperature of the resulting reaction mixture was returned to room temperature, and 2 M hydrochloric acid (1 mL) was added thereto. Further, mesitylene (5.0 μL, 0.036 mmol) was added thereto, and １ H NMR analysis confirmed that the target products, 4,4'-dihydroxybenzophenone (corresponding to compound (21)), hydroquinone (corresponding to compound (122)), and (4-(4-hydroxyphenoxy)-phenyl)(4-hydroxyphenyl)methanone, were obtained.

[0869] Next, ethyl acetate (30 mL) and water (30 mL) were added to the reaction mixture obtained above, and the mixture was stirred, and the organic layer was extracted. The o...

Claims

1. The following general formula (1) (In the formula, n １ is an integer of 2 or more; Z １１ and Z １２ are each independently a group other than a hydrogen atom; m １１ and m １２ are each independently an integer of 0 to 4, and m １１ When n is an integer of 1 or more, １ ×m １１ Z １１ may be the same or different, m １２ When n is an integer of 1 or more, １ ×m １２ Z １２ may be the same or different; Ar １ is represented by the following general formula (91), (92) or (93): (In the formula, X １１ , X １２ , X ２１ , X ３１ and X ３２ are each independently a group other than a hydrogen atom; １１ , l １２ , l ２１ , l ３１ and l ３２ are each independently an integer of 0 to 4, １１ When n is an integer of 1 or more, １ ×l １１ X of pieces １１ may be the same or different, １２ When n is an integer of 1 or more, １ ×l １２ X of pieces １２ may be the same or different, ２１ When n is an integer of 1 or more, １ ×l ２１ X of pieces ２１ may be the same or different, ３１ When n is an integer of 1 or more, １ ×l ３１ X of pieces ３１ may be the same or different, ３２ When n is an integer of 1 or more, １ ×l ３２ X of pieces ３２ may be the same or different from each other.) In the general formulae (91), (92), and (93), the bond marked with * and the bond marked with ** are each formed relative to the oxygen atom in the general formula (1). a first compound represented by In the presence of a base, a compound represented by the following general formula (8) R ８ -SMH (8) (In the formula, R ８ represents an alkyl group, an aryl group, or an aralkyl group, and one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group. or a hydroxide thereof, a decomposition step of decomposing the first compound, How compounds are broken down.

2. The following general formula (2) (In the formula, n ２ is an integer of 2 or more; Z ２１ , Z ２２ and Z ２３ are each independently a group other than a hydrogen atom; m ２１ , m ２２ and m ２３ are each independently an integer of 0 to 4, and m ２１ When n is an integer of 1 or more, ２ ×m ２１ Z ２１ may be the same or different, m ２２ When n is an integer of 1 or more, ２ ×m ２２ Z ２２ may be the same or different, m ２３ When n is an integer of 1 or more, ２ ×m ２３ Z ２３ may be the same or different.) and a third compound represented by In the presence of base Methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, n-butyl mercaptan, isobutyl mercaptan, sec-butyl mercaptan, tert-butyl mercaptan, n-pentyl mercaptan, isopentyl mercaptan, neopentyl mercaptan, tert-pentyl mercaptan, 1-methylbutyl mercaptan, 2-methylpentyl mercaptan, 3-methylpentyl mercaptan, 2,2-dimethylbutyl mercaptan, 2,3-dimethylbutyl mercaptan, n-heptyl mercaptan, 2-methylhexyl mercaptan, 3- Methylhexyl mercaptan, 2,2-dimethylpentyl mercaptan, 2,3-dimethylpentyl mercaptan, 2,4-dimethylpentyl mercaptan, 3,3-dimethylpentyl mercaptan, 3-ethylpentyl mercaptan, 2,2,3-trimethylbutyl mercaptan, n-octyl mercaptan, isooctyl mercaptan, 2-ethylhexyl mercaptan, nonyl mercaptan, decyl mercaptan, 3,7-dimethyloctyl mercaptan, undecyl mercaptan, dodecyl mercaptan, tridecyl mercaptan, tetradecyl mercaptan, pentadecyl mercaptan, cyclopropyl mercaptan, cyclobutyl mercaptan, cyclopentyl mercaptan, cyclohexyl mercaptan, cycloheptyl mercaptan, cyclooctyl mercaptan, cyclononyl mercaptan, cyclodecyl mercaptan, norbornyl mercaptan, isobornyl mercaptan, 1-adamantyl mercaptan, 2-adamantyl mercaptan, tricyclodecyl mercaptan, cyclopropyl methyl mercaptan, Phenyl mercaptan, 1-naphthyl mercaptan, 2-naphthyl mercaptan, o-tolyl mercaptan, m-tolyl mercaptan, p-tolyl mercaptan, 4-tert-butylphenyl mercaptan, xylyl mercaptan (dimethylphenyl mercaptan) 4-tert-butylbenzyl mercaptan, 4-tert-butylphenethyl mercaptan, 1-naphthyl methyl mercaptan, 2-naphthyl methyl mercaptan, m-tolyl methyl mercaptan, xylyl methyl mercaptan, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecanethiol, 4-chlorophenyl mercaptan, (3-mercaptopropyl)triethoxysilane or 1-mercapto-2-methylcarbonyloxyethane or hydroxide, a decomposition step of decomposing the third compound, How compounds are broken down.

3. The following general formula (4) (In the formula, n ４ is an integer of 2 or more; Z ４１ and Z ４２ are each independently a group other than a hydrogen atom; m ４１ and m ４２ are each independently an integer of 0 to 4, and m ４１ When n is an integer of 1 or more, ４ ×m ４１ Z ４１ may be the same or different, m ４２ When n is an integer of 1 or more, ４ ×m ４２ Z ４２ may be the same or different.) and a fourth compound represented by In the presence of a base, a compound represented by the following general formula (8) R ８ -SMH (8) (In the formula, R ８ represents an alkyl group, an aryl group, or an aralkyl group, and one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group. or a hydroxide thereof, a decomposition step of decomposing the fourth compound, How compounds are broken down.

4. 4. The method for depolymerizing a compound according to claim 1, wherein at least one of a phosphazene base and sodium tert-butoxide is used as the base.

5. The method for decomposing a compound according to any one of claims 1 to 3, wherein the second compound represented by the general formula (8) is one or more compounds selected from the group consisting of alkyl mercaptans having 1 to 15 carbon atoms, aryl mercaptans having 6 to 12 carbon atoms, aralkyl mercaptans having 7 to 14 carbon atoms, halogenated alkyl mercaptans having 1 to 15 carbon atoms, halogenated aryl mercaptans having 6 to 12 carbon atoms, hydroxyalkyl mercaptans having 1 to 15 carbon atoms, polymercaptoalkanes having 1 to 15 carbon atoms, (mercaptoalkyl)trialkoxysilanes having 4 to 15 carbon atoms, and alkoxycarbonylalkanethiols having 3 to 15 carbon atoms.

6. The method for decomposing a compound according to any one of claims 1 to 3, wherein a dehydrating agent is further used in the decomposition step.

7. The method for decomposing a compound according to any one of claims 1 to 3, wherein the hydroxide is an alkali metal hydroxide.

8. 7. The method for decomposing a compound according to claim 6, wherein the dehydrating agent is one or more selected from the group consisting of sodium hydride, potassium hydride, calcium hydride, calcium oxide, cesium chloride, calcium chloride, magnesium sulfate, and zeolite.

9. The compound represented by the following general formula (11), obtained by the method for decomposing a compound according to any one of claims 1 to 3: (In the formula, Z １１ , Z １２ , m １１ and m １２ is the same as above.) a compound represented by the formula (I) or a salt thereof, The following general formula (121) (In the formula, X １１ , X １２ , l １１ and l １２ is the same as above.) and salts thereof, The following general formula (122) (In the formula, X ２１ and l ２１ are the same as above.) and salts thereof, The following general formula (123) (In the formula, X ３１ , X ３２ , l ３１ and l ３２ is the same as above.) and salts thereof, The following general formula (21) (In the formula, Z ２１ , Z ２２ , m ２１ and m ２２ is the same as above.) and a compound represented by the following general formula (22) (In the formula, Z ２３ and m ２３ is the same as above.) and salts thereof, Or the following general formula (41) (In the formula, Z ４１ , Z ４２ , m ４１ and m ４２ is the same as above.) and salts thereof. Etherification of one or more phenolic hydroxyl groups or groups resulting from the formation of salts of the phenolic hydroxyl groups to obtain an ether compound.

10. The following general formula (3) (In the formula, n ３ is an integer of 2 or more; Z ３１ , Z ３２ , Z ３３ , Z ３４ and Z ３５ are each independently a group other than a hydrogen atom; m ３１ and m ３２ are each independently an integer of 0 to 3, and m ３３ , m ３４ and m ３５ are each independently an integer of 0 to 4, and m ３１ When n is an integer of 1 or more, ３ ×m ３１ Z ３１ may be the same or different, m ３２ When n is an integer of 1 or more, ３ ×m ３２ Z ３２ may be the same or different, m ３３ When n is an integer of 1 or more, ３ ×m ３３ Z ３３ may be the same or different, m ３４ When n is an integer of 1 or more, ３ ×m ３４ Z ３４ may be the same or different, m ３５ When n is an integer of 1 or more, ３ ×m ３５ Z ３５ may be the same or different.) and a fifth compound represented by In the presence of a base, a compound represented by the following general formula (8) R ８ -SMH (8) (In the formula, R ８ represents an alkyl group, an aryl group, or an aralkyl group, and one or more hydrogen atoms in the alkyl group, aryl group, or aralkyl group may be substituted with a halogen atom, a hydroxyl group, a mercapto group, or a trialkoxysilyl group, and when the alkyl group, aryl group, or aralkyl group has one or more trimethylene groups therein, the central methylene group in the trimethylene group may be substituted with an oxycarbonyl group or a carbonyloxy group. and a second compound represented by a decomposition step of decomposing the fifth compound, How compounds are broken down.

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