Catalyst for alcoholysis of polycarbonate resin, method for decomposing polycarbonate resin, and method for producing diol

Abstract

To provide a catalyst for alcoholysis of a polycarbonate resin, a method for decomposing a polycarbonate resin, and a method for producing a diol, which enable alcoholysis of the polycarbonate resin to proceed under moderate reaction conditions and allow efficient acquisition of a diol compound formed as a reaction product.SOLUTION: There are provided a catalyst for alcoholysis of a polycarbonate resin comprising a rare earth metal complex containing a rare earth metal (A) and a ligand (B), wherein the ligand (B) includes at least one compound represented by a specific general formula, a method for decomposing a polycarbonate resin using the catalyst for alcoholysis of a polycarbonate resin, and a method for producing a diol.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a catalyst for alcoholysis of a polycarbonate resin, a method for decomposing a polycarbonate resin, and a method for producing a diol. [Background technology]

[0002] Plastic is easily accessible, durable, and inexpensive, and is therefore produced in large quantities not only in Japan but all over the world. Because much of this plastic is used as a "disposable" item, it is not properly disposed of and some ends up in the environment. Specifically, plastic waste flows from rivers into the ocean, where it is degraded by waves and ultraviolet light, becoming smaller than 5mm. These tiny pieces of plastic waste are called microplastics. Animals and fish can accidentally ingest these microplastics. Plastic waste thus has a significant impact on ecosystems, and in recent years, the marine plastic problem has become a global concern. Polycarbonate resins are used in a wide range of fields due to their transparency, mechanical properties, flame retardancy, dimensional stability, and electrical properties, and this polycarbonate resin is no exception.

[0003] One method of recycling polycarbonate resin is chemical recycling, in which polycarbonate resin is chemically decomposed and returned to bisphenol, which can then be reused.Alcoholysis is also known as a method of decomposing polycarbonate resin. For example, Non-Patent Document 1 discloses a method for obtaining bisphenol A by reacting poly(bisphenol A carbonate) in methanol in the presence of a catalytic amount of a lanthanum complex having a β-diketone type ligand. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Chemical Society of Japan, 104th Spring Annual Meeting (2024), Abstracts, E1142-2pm-06 Summary of the Invention [Problem to be solved by the invention]

[0005] The invention disclosed in Non-Patent Document 1 leaves room for improvement in the yield of bisphenol A, which is the reaction product in the depolymerization reaction of poly(bisphenol A carbonate). Therefore, there has been a demand for an efficient production of a diol compound, which is a reaction product, in the alcoholysis of a polycarbonate resin.

[0006] An object of one aspect of the present disclosure is to provide a catalyst for alcoholysis of a polycarbonate resin, which allows alcoholysis of a polycarbonate resin to proceed under mild reaction conditions and efficiently produce a diol compound as a reaction product, a method for decomposing a polycarbonate resin, and a method for producing a diol. [Means for solving the problem]

[0007] The means for solving the above problems include the following aspects. <1> A catalyst for alcoholysis of a polycarbonate resin (C), comprising a rare earth complex containing a rare earth metal (A) and a ligand (B), wherein the ligand (B) comprises a compound represented by the following general formula (1):

[0008] [ka]

[0009] [In general formula (1), R 1 and R 2 are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, and R 3 and R 4 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. <2> In general formula (1), R 1 is a substituted or unsubstituted benzene ring having 6 to 8 carbon atoms, and R2 is an unsubstituted alkyl group having 1 to 3 carbon atoms, and R 3 and R 4 is a hydrogen atom, <1> Catalyst for alcoholysis of polycarbonate resin according to claim 1. <3> The rare earth metal (A) comprises at least one metal selected from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium; <1> or <2> Catalyst for alcoholysis of polycarbonate resin according to claim 1. <4> <1> ~ <3> 1. A method for decomposing a polycarbonate resin, comprising reacting a polycarbonate resin (C) with an aliphatic alcohol having 1 to 10 carbon atoms in the presence of the alcoholysis catalyst for a polycarbonate resin described in any one of 1. to 10. <5> reacting the polycarbonate resin (C) with an aliphatic alcohol having 1 to 3 carbon atoms at a temperature equal to or lower than the boiling point of the aliphatic alcohol; <4> 1. A method for decomposing a polycarbonate resin according to claim 1. <6> reacting the polycarbonate resin (C) with an aliphatic alcohol having one carbon atom at a temperature equal to or lower than the boiling point of the aliphatic alcohol; <4> 1. A method for decomposing a polycarbonate resin according to claim 1. <7> The polycarbonate resin (C) contains at least one selected from the group consisting of aromatic polycarbonates (C-1) and aliphatic polycarbonates (C-2). <4> ~ <6> 10. The method for decomposing a polycarbonate resin according to claim 9, wherein the polycarbonate resin is a polycarbonate resin. <8> The polycarbonate resin (C) contains an aromatic polycarbonate (C-1). <4> ~ <6> 1. A method for decomposing a polycarbonate resin according to claim 1. <9> <1> ~ <3> 1. A method for producing a diol, comprising reacting a polycarbonate resin (C) with an aliphatic alcohol in the presence of the catalyst for alcoholysis of a polycarbonate resin according to any one of the above items 1 to 8. <10> reacting the polycarbonate resin (C) with an aliphatic alcohol having one carbon atom at a temperature equal to or lower than the boiling point of the aliphatic alcohol; <9> 1. A method for producing the diol described in <11> The polycarbonate resin (C) contains an aromatic polycarbonate (C-1). <9> 1. A method for producing the diol described in <12> Producing aromatic diols, <9> 1. A method for producing the diol described in [Effects of the Invention]

[0010] According to one aspect of the present disclosure, there are provided a catalyst for alcoholysis of a polycarbonate resin, a method for decomposing a polycarbonate resin, and a method for producing a diol, which allow alcoholysis of a polycarbonate resin to proceed under mild reaction conditions and efficiently produce a diol compound as a reaction product. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure will be described below. However, although the following description of the components may be based on representative embodiments of the present disclosure, the present disclosure is not limited to such embodiments.

[0012] In the present disclosure, combinations of preferred aspects are more preferred aspects. In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In the numerical ranges described in stages in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. In the present disclosure, when a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified. In the present disclosure, "contains mainly" means that the target substance is contained in the largest amount relative to the whole. For example, this means that the content of the target substance is 50% by mass or more relative to the whole. In this disclosure, "mass%" and "wt%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. In this disclosure, "%" indicating the amount of a component is based on mass unless otherwise specified. In this disclosure, boiling points are those under standard conditions (1 atmosphere, 25°C).

[0013] A catalyst for alcoholysis of a polycarbonate resin (hereinafter also referred to as an alcoholysis catalyst) according to one embodiment of the present disclosure comprises a rare earth complex containing a rare earth metal (A) and a ligand (B), wherein the ligand (B) has a structure represented by a specific general formula:

[0014] (1) Alcoholysis catalyst The alcoholysis catalyst comprises a rare earth complex comprising a rare earth metal (A) and a ligand (B).

[0015] (2) Rare earth complexes The rare earth complex contains a rare earth metal (A) and a ligand (B). The rare earth complex preferably has one or more ligands (B) coordinated to one rare earth metal (A). For example, two or three ligands (B) may be coordinated to one rare earth metal (A). There is no particular upper limit on the number of ligands (B) coordinated to one rare earth metal (A), but, for example, the number of ligands (B) may be 10 or less. The rare earth complex can be obtained as a solid that is poorly soluble in water or methanol by ligand exchange between a chloride or hydrate of a rare earth metal (A) and a ligand (B) in water or methanol under basic conditions.

[0016] (3) Rare earth metals (A) From the viewpoint of promoting alcoholysis of the polycarbonate resin under milder reaction conditions and efficiently obtaining a diol, the rare earth metal (A) preferably contains at least one metal selected from the group consisting of yttrium (Y) and lanthanoid elements (e.g., lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu)). Mild reaction conditions include, for example, mild conditions for the reaction temperature, reaction pressure, etc. The alcoholysis of the polycarbonate resin can be carried out at a relatively low reaction temperature (e.g., 65°C to 140°C) below the boiling point of the aliphatic alcohol that is the raw material for the alcoholysis, and at a standard pressure (atmospheric pressure) rather than under pressurized conditions.

[0017] From the viewpoint of efficiently obtaining a diol, it is more preferable to have at least one metal selected from the group consisting of yttrium, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, it is even more preferable to have at least one metal selected from the group consisting of yttrium, lanthanum, neodymium, gadolinium, and ytterbium, it is particularly preferable to include lanthanum, and it is extremely preferable to be lanthanum. The rare earth metal (A) contained in the rare earth complex may contain two or more different rare earth metals (A), but preferably contains one type. Furthermore, the rare earth complex may further contain a metal other than the rare earth metal (A) listed above. Examples of metals other than the rare earth metal (A) include transition metals, and any metal contained in transition metals, such as iron and copper, may be contained.

[0018] (4)Ligand (B) The ligand (B) includes a compound represented by the following general formula (1).

[0019] [ka]

[0020] In general formula (1), R 1 and R 2 are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, and R 3 and R 4 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms.

[0021] In one embodiment of the present disclosure, the inventors speculate that the alcoholysis reaction of polycarbonate resin (C) catalyzed by a rare earth complex containing a rare earth metal (A) and a ligand (B) proceeds by forming an intermediate in which two or more rare earth complexes (e.g., lanthanum complexes) are crosslinked with a solvent-derived alkoxide, and by the concerted nucleophilic attack of the alkoxide and the activation of the carbonyl group of the rare earth element (e.g., lanthanum). The inventors speculate that, as a result, the structure of the ligand (B) has an appropriate amount of electron-donating substituent, i.e., an ester group at the end, as in one embodiment of the present disclosure, which stabilizes the intermediate, and as a result, the diol compound, which is the product, can be efficiently obtained.

[0022] (4-1)R 1 and R 2 In the following general formula (1), R 1 and R 2 are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms.

[0023] [ka]

[0024] R 1 Specific examples of the substituted or unsubstituted alkyl group having 1 to 10 carbon atoms in the formula (I) include linear alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group; Isopropyl, isobutyl, sec-butyl, isopentyl, sec-pentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 1-ethylpentyl, 2-ethylpentyl, 3-ethylpentyl, 1-n-propylbutyl, 1-isopropylbutyl, 1-isopropyl-2-methylpropyl, 1-methylheptyl monoalkyl-substituted alkyl groups having 2 to 10 carbon atoms, such as a 2-methylheptyl group, a 3-methylheptyl group, a 4-methylheptyl group, a 5-methylheptyl group, a 6-methylheptyl group, a 1-ethylhexyl group, a 2-ethylhexyl group, a 3-ethylhexyl group, a 4-ethylhexyl group, a 1-n-propylpentyl group, a 2-n-propylpentyl group, a 1-iso-propylpentyl group, a 2-iso-propylpentyl group, a 1-n-butylbutyl group, a 1-iso-butylbutyl group, a 1-sec-butylbutyl group, a 1-tert-butylbutyl group, and a 2-tert-butylbutyl group;

[0025] tert-Butyl group, tert-pentyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1,1-dimethylpentyl group, 1,2-dimethylpentyl group, 1,3-dimethylpentyl group, 1,4-dimethylpentyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 3,4-dimethylpentyl group butyl group, 1-ethyl-1-methylbutyl group, 1-ethyl-2-methylbutyl group, 1-ethyl-3-methylbutyl group, 2-ethyl-1-methylbutyl group, 2-ethyl-3-methylbutyl group, 1,1-dimethylhexyl group, 1,2-dimethylhexyl group, 1,3-dimethylhexyl group, 1,4-dimethylhexyl group, 1,5-dimethylhexyl group, 2,2-dimethylhexyl group, 2,3-dimethylhexyl group, 2,4-dimethylhexyl group, 2,5-dimethylhexyl group, 3 ,3-dimethylhexyl group, 3,4-dimethylhexyl group, 3,5-dimethylhexyl group, 4,4-dimethylhexyl group, 4,5-dimethylhexyl group, 1-ethyl-2-methylpentyl group, 1-ethyl-3-methylpentyl group, 1-ethyl-4-methylpentyl group, 2-ethyl-1-methylpentyl group, 2-ethyl-2-methylpentyl group, 2-ethyl-3-methylpentyl group, 2-ethyl-4-methylpentyl group, 3-ethyl-1-methylpentyl group, 3-ethyl-2 dialkyl-substituted alkyl groups having 3 to 10 carbon atoms, such as a 1-methylpentyl group, a 3-ethyl-3-methylpentyl group, a 3-ethyl-4-methylpentyl group, a 1-n-propyl-1-methylbutyl group, a 1-n-propyl-2-methylbutyl group, a 1-n-propyl-3-methylbutyl group, a 1-iso-propyl-1-methylbutyl group, a 1-iso-propyl-2-methylbutyl group, a 1-iso-propyl-3-methylbutyl group, a 1,1-diethylbutyl group, and a 1,2-diethylbutyl group;

[0026] 1,1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group, 1,1,2-trimethylbutyl group, 1,1,3-trimethylbutyl group, 1,2,3-trimethylbutyl group, 1,2,2-trimethylbutyl group, 1,3,3-trimethylbutyl group, 2,3,3-trimethylbutyl group, 1,1,2-trimethylpentyl group, 1,1,3-trimethylpentyl group, 1,1,4-trimethylpentyl group, 1,2,2-trimethylpentyl group, 1,2,3-trimethylpentyl group, 1,2,4-trimethylpentyl group, 1,3,4-trimethylpentyl group, 2,2,3-trimethylpentyl group, 2,2,4-trimethylpentyl group trialkyl-substituted alkyl groups having 4 to 10 carbon atoms, such as a methyl group, a 2,3,4-trimethylpentyl group, a 1,3,3-trimethylpentyl group, a 2,3,3-trimethylpentyl group, a 3,3,4-trimethylpentyl group, a 1,4,4-trimethylpentyl group, a 2,4,4-trimethylpentyl group, a 3,4,4-trimethylpentyl group, a 1-ethyl-1,2-dimethylbutyl group, a 1-ethyl-1,3-dimethylbutyl group, a 1-ethyl-2,3-dimethylbutyl group, a 2-ethyl-1,1-dimethylbutyl group, a 2-ethyl-1,2-dimethylbutyl group, a 2-ethyl-1,3-dimethylbutyl group, and a 2-ethyl-2,3-dimethylbutyl group;

[0027] cyclic alkyl groups having 3 to 10 carbon atoms, such as a cyclopentyl group and a cyclohexyl group; alkyl-substituted cyclic alkyl groups having 4 to 10 carbon atoms, such as a methylcyclopentyl group, a methylcyclohexyl group, a 1,2-dimethylcyclohexyl group, a 1,3-dimethylcyclohexyl group, a 1,4-dimethylcyclohexyl group, and an ethylcyclohexyl group; aryl-substituted alkyl groups having 7 to 10 carbon atoms, such as a benzyl group and a 4-methylbenzyl group; halogenated alkyl groups having 1 to 10 carbon atoms, some or all of which are substituted with halogen atoms, such as a fluoromethyl group, a trifluoromethyl group, a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a fluoroethyl group, a chloroethyl group, a bromoethyl group, a trifluoroethyl group, a pentafluoroethyl group, a tetrachloroethyl group, and a hexafluoroisopropyl group; Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0028] Specific examples of the substituted or unsubstituted aryl group having 6 to 10 carbon atoms include: an aryl group having 6 to 10 carbon atoms, such as a phenyl group or a naphthyl group; monoalkyl-substituted aryl groups having 7 to 10 carbon atoms, such as a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 2-ethylphenyl group, a propylphenyl group, and a butylphenyl group; dialkyl-substituted aryl groups having 8 to 10 carbon atoms, such as a 2,3-dimethylphenyl group, a 2,4-dimethylphenyl group, a 2,5-dimethylphenyl group, a 2,6-dimethylphenyl group, a 3,4-dimethylphenyl group, a 3,5-dimethylphenyl group, and a 3,6-dimethylphenyl group; trialkyl-substituted aryl groups having 9 or 10 carbon atoms, such as a 2,3,4-trimethylphenyl group, a 2,3,5-trimethylphenyl group, a 2,3,6-trimethylphenyl group, a 2,4,5-trimethylphenyl group, a 2,4,6-trimethylphenyl group, or a 3,4,5-trimethylphenyl group;

[0029] a monoalkoxyaryl group having 7 to 10 carbon atoms substituted with a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a 2-methoxyphenyl group, a 3-methoxyphenyl group, a 4-methoxyphenyl group, a 2-ethoxyphenyl group, a propoxyphenyl group, or a butoxyphenyl group; dialkoxyaryl groups having 8 to 10 carbon atoms substituted with a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a 2,3-dimethoxyphenyl group, a 2,4-dimethoxyphenyl group, a 2,5-dimethoxyphenyl group, a 2,6-dimethoxyphenyl group, a 3,4-dimethoxyphenyl group, a 3,5-dimethoxyphenyl group, or a 3,6-dimethoxyphenyl group; trialkoxyaryl groups having 9 or 10 carbon atoms substituted with a substituted or unsubstituted alkoxy group having 4 or less carbon atoms, such as a 2,3,4-trimethoxyphenyl group, a 2,3,5-trimethoxyphenyl group, a 2,3,6-trimethoxyphenyl group, a 2,4,5-trimethoxyphenyl group, a 2,4,6-trimethoxyphenyl group, or a 3,4,5-trimethoxyphenyl group; an aryl group having 6 to 10 carbon atoms substituted with a halogen atom, such as a chlorophenyl group, a dichlorophenyl group, a trichlorophenyl group, a bromophenyl group, a dibromophenyl group, an iodophenyl group, a fluorophenyl group, a chloronaphthyl group, a bromonaphthyl group, a difluorophenyl group, a trifluorophenyl group, a tetrafluorophenyl group, or a pentafluorophenyl group;

[0030] halogenated alkylaryl groups having 7 to 10 carbon atoms substituted with alkyl groups having 4 or less carbon atoms and which are partially or fully substituted with halogen, such as trifluoromethylphenyl groups and trichloromethylphenyl groups; N,N-dimethylaminophenyl group, N,N-diethylaminophenyl group, N,N-disubstituted amino-substituted aryl groups having 10 or less carbon atoms, such as N-tolyl-N-ethylaminophenyl group and N,N-ditolylaminophenyl group; alkylthioaryl groups such as a methylthiophenyl group and an ethylthiophenyl group; and the like.

[0031] R 1 is preferably a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms or a substituted or unsubstituted benzene ring having 6 to 8 carbon atoms, more preferably a substituted or unsubstituted benzene ring having 6 to 8 carbon atoms, and even more preferably an unsubstituted benzene ring having 6 carbon atoms. R 2As the alkyl group, a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms is preferred, and a substituted or unsubstituted alkyl group having 1 to 2 carbon atoms is more preferred.

[0032] (4-2)R 3 and R 4 In the above general formula (1), R 3 and R 4 are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms. Specific examples of the substituted or unsubstituted alkyl group having 1 to 3 carbon atoms include: linear alkyl groups having 1 to 3 carbon atoms, such as a methyl group, an ethyl group, or an n-propyl group; a monoalkyl-substituted alkyl group having 2 to 3 carbon atoms, such as an isopropyl group; a dialkyl-substituted alkyl group having 3 carbon atoms, such as a tert-butyl group; halogenated alkyl groups having 1 to 3 carbon atoms, some or all of which are substituted with halogen atoms, such as a fluoromethyl group, a trifluoromethyl group, a chloromethyl group, a dichloromethyl group, a trichloromethyl group, a bromomethyl group, a dibromomethyl group, a tribromomethyl group, a fluoroethyl group, a chloroethyl group, a bromoethyl group, a trifluoroethyl group, a pentafluoroethyl group, a tetrachloroethyl group, and a hexafluoroisopropyl group; Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0033] R 3 and R 4 are each preferably independently a hydrogen atom or an unsubstituted methyl group, and R 3 and R 4 It is more preferable that all of the groups are hydrogen atoms.

[0034] (4-3) Examples of Ligand (B) The ligand (B) is represented by the general formula (1) above, R 1 is a substituted or unsubstituted benzene ring having 6 to 8 carbon atoms, and R 2 is an unsubstituted alkyl group having 1 to 3 carbon atoms, and R3 and R 4 are preferably both hydrogen atoms.

[0035] Specific examples of the ligand (B) include ethyl 3-oxobutyrate and ethyl 3-oxo-3-phenylpropanoate. Of these, ethyl 3-oxobutyrate and ethyl 3-oxo-3-phenylpropanoate are preferably used as the ligand (B).

[0036] (5) Polycarbonate resin (C) The polycarbonate resin (C) is a resin containing a polymer composition containing a carbonate bond (—O—C(═O)—O—). The polycarbonate resin (C) preferably contains at least one selected from the group consisting of aromatic polycarbonates (C-1) and aliphatic polycarbonates (C-2) described below, more preferably contains aromatic polycarbonate (C-1), and even more preferably contains only aliphatic polycarbonate resin (C-2). The polycarbonate resin (C) may contain polycarbonate resins other than those mentioned above, as long as the effects of the present disclosure are not impaired.

[0037] (5-1) Aromatic polycarbonate (C-1) The aromatic polycarbonate (C-1) is a polycarbonate resin having an aromatic ring (benzene ring) in the molecule. The aromatic polycarbonate (C-1) may be any polycarbonate resin having an aromatic ring (benzene ring) in the molecule.

[0038] A specific example of the aromatic polycarbonate (C-1) includes a polymer containing a structural unit derived from bisphenol, which is represented by the following general formula (2).

[0039] [ka]

[0040] In general formula (2), R21 ~R 24 The substituents of each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, etc. Examples thereof include a hydrogen atom, a fluoro group, a chloro group, a bromo group, an iodo group, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, and a t-butoxy group. Examples of such groups include an n-pentyloxy group, an i-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, and a 2,6-dimethylphenyl group.

[0041] R 25 and R 26 The substituents of each independently include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, etc. Examples thereof include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a t-butoxy ... i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, an i-pentyl group, Examples of such an alkyl group include an n-butyloxy group, an i-pentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, and a 2,6-dimethylphenyl group.

[0042] R 25 and R 26 may be bonded or bridged to each other to form a cycloalkylidene group, such as cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclododecylidene, fluorenylidene, xanthonylidene, and thioxanthonylidene.

[0043] As the aromatic polycarbonate (C-1), particularly, R 21 ~R 24 are hydrogen atoms, and R 25 and R 26 are each a methyl group (bisphenol A polycarbonate resin). That is, the aromatic polycarbonate (C-1) is preferably poly[2,2-bis(4-hydroxyphenyl)propane]. In the general formula (2), n is not particularly limited, but is, for example, 2 to 1,000. The mass average molecular weight (Mw) of the aromatic polycarbonate (C-1) is not particularly limited, but may be, for example, about 500 to 250,000.

[0044] (5-2) Aliphatic polycarbonate (C-2) The aliphatic polycarbonate (C-2) is not particularly limited as long as the main chain contains only aliphatic groups. For example, aliphatic polycarbonates obtained by copolymerization of a cyclic ether and carbon dioxide, aliphatic polycarbonates obtained by polycondensation of an aliphatic diol with carbon dioxide, phosgene, a carbonate diester, or the like, aliphatic polycarbonates obtained by ring-opening polymerization of a cyclic carbonate, and aliphatic polycarbonates obtained by polycondensation of an aliphatic dihalide with a carbonate can be used.

[0045] The aliphatic polycarbonate (C-2) specifically includes, for example, a structural unit having a carbonate bond represented by the following general formula (3).

[0046] [ka]

[0047] Here, in general formula (3), R 31 , R 32 , R 33 , and R 34 are the same or different and represent a hydrogen atom, a linear or branched alkyl group having 1 to 5 carbon atoms which may be substituted, or an aryl group having 6 to 20 carbon atoms which may be substituted. 31 , R 32 , R 33 , and R 34 Two of these may be bonded to each other to form an aliphatic ring having 3 to 10 ring members which may be substituted with a substituent. In the general formula (3), the linear or branched alkyl group having 1 to 5 carbon atoms is a linear or branched alkyl group. The number of carbon atoms in this alkyl group is preferably 1 to 4, and more preferably 1 or 2. More specific examples include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. In the general formula (3), the aryl group having 6 to 20 carbon atoms preferably has a carbon number of 6 to 14. Examples thereof include a phenyl group, a naphthyl group, and a tetrahydronaphthyl group. In general formula (3), R 31 , R 32 , R 33 , and R 34 can be the same, or some or all may be different. In general formula (3), R 31 , R 32 , R 33 , and R 34 Two of these may be bonded to each other to form an aliphatic ring having 3 to 10 ring members which may be substituted with a substituent.

[0048] The aliphatic polycarbonate (C-2) preferably contains one or more polycarbonate resins selected from the group consisting of polyethylene carbonate, polypropylene carbonate, and polybutylene carbonate, and more preferably contains polypropylene carbonate. In the aliphatic polycarbonate (C-2), the proportion of ether bonds relative to the total amount of carbonate bonds and ether bonds is preferably 10 mol% or less, and the lower limit of this proportion is not particularly limited, but may be, for example, 0.05 mol% or more.

[0049] The aliphatic polycarbonate (C-2) can be produced, for example, by polymerizing epoxide with carbon dioxide. The epoxide used to produce the aliphatic polycarbonate (C-2) is not particularly limited, but preferred examples include ethylene oxide, propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. The mass average molecular weight (Mw) of the aliphatic polycarbonate (C-2) is not particularly limited, but may be, for example, about 200 to 200,000.

[0050] The polycarbonate resin (C) may be not only a polycarbonate resin alone, but also a composition containing a resin other than a polycarbonate resin, such as a copolymer or a polymer alloy. Examples of compositions containing a resin other than polycarbonate resin include polycarbonate / polyester copolymer, polycarbonate / polyester alloy, polycarbonate / polyarylate copolymer, polycarbonate / polyarylate alloy, etc. When using a composition containing a resin other than polycarbonate resin, it is preferable to use one in which polycarbonate resin is the main component (the composition contains 50% by mass or more of polycarbonate resin). The polycarbonate resin (C) may be a mixture of two or more different polycarbonate resins, although a single polycarbonate resin may simply be called polycarbonate.

[0051] In addition, waste aromatic polycarbonate can be used as the polycarbonate resin (C). For example, waste optical discs such as CDs, CD-Rs, and DVDs that have been discarded or have been defectively molded during the manufacturing process and are discarded as unwanted products can be used as the polycarbonate resin (C), either as is or after removing the printed film or metal film. The waste aromatic polycarbonate used may also be a solid product obtained by removing the solvent from a solution of polycarbonate that did not reach the target molecular weight during polycarbonate production and was not powdered or pelletized, and then dried.

[0052] (6) Method for decomposing polycarbonate resin and method for producing diol A method for decomposing a polycarbonate according to one embodiment of the present disclosure (hereinafter also referred to as a polycarbonate decomposition method) comprises reacting a polycarbonate resin (C) with an aliphatic alcohol having 1 to 10 carbon atoms in the presence of any of the alcoholysis catalysts described above. The polycarbonate resin (C) is decomposed using the above-mentioned catalyst for alcoholysis of polycarbonate resin and an aliphatic alcohol having 1 to 10 carbon atoms to obtain a diol.

[0053] An aliphatic alcohol having 1 to 10 carbon atoms is represented by "Z-OH." Z is preferably an unsubstituted alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a 1-methylpropyl group, a pentyl group, a 1-methylbutyl group, a hexyl group, a 1-methylpentyl group, a heptyl group, an octyl group, a 1-methylheptyl group, a nonyl group, and a decyl group. Among these, from the viewpoint of efficiency of the decomposition reaction, unsubstituted alkyl groups having 1 to 5 carbon atoms are more preferred (e.g., methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, tert-butanol, 1-methylpropanol, pentanol, 1-methylbutanol), unsubstituted alkyl groups having 1 to 3 carbon atoms are even more preferred (e.g., methanol, ethanol, propanol), and unsubstituted alkyl groups having 1 carbon atom are particularly preferred (e.g., methanol).

[0054] Preferably, an aliphatic alcohol having 1 to 10 carbon atoms is used as the solvent, more preferably, the solvent contains methanol, and even more preferably, the solvent contains only methanol.

[0055] The concentration (mol / L; hereinafter also referred to as "M") of the amount of substance (mol) of the raw material polycarbonate resin (C) relative to the volume (L) of the solvent is preferably 1.0 M or less, more preferably 0.8 M or less, even more preferably 0.6 M or less, and particularly preferably 0.4 M or less. There is no particular lower limit, but it may be, for example, 0.05 M or more, or 0.1 M or more.

[0056] The method for decomposing the polycarbonate resin is preferably a method in which the polycarbonate resin (C) is reacted with an aliphatic alcohol having 1 to 10 carbon atoms at a temperature equal to or lower than the boiling point of the aliphatic alcohol. In the method for decomposing a polycarbonate resin, since the above-mentioned specific catalyst for alcoholysis of a polycarbonate resin is used, even when the reaction is carried out at a temperature below the boiling point of the aliphatic alcohol used, a diol compound as a reaction product can be efficiently obtained. Carrying out the reaction at a temperature below the boiling point of the aliphatic alcohol used is a milder reaction condition than carrying out the reaction at a temperature above the boiling point. Furthermore, in the method for decomposing polycarbonate resin, the reaction is carried out at a reaction temperature below the boiling point of the aliphatic alcohol used, which eliminates the need for pressurized conditions, simplifies the equipment, and also reduces costs. The method for decomposing a polycarbonate resin allows the alcoholysis of the polycarbonate resin to proceed under such milder reaction conditions, and is also excellent in the yield of the diol compound, which is the reaction product, and in the amount recovered per unit time, making it a method for efficiently obtaining a diol. From the viewpoint of the balance between energy efficiency and diol yield, the reaction temperature for the decomposition reaction of the polycarbonate resin (C) is preferably 140°C or lower, more preferably 120°C or lower, even more preferably 100°C or lower, particularly preferably 80°C or lower, and extremely preferably 65°C or lower. There is no particular restriction on the lower limit, but it may be, for example, 45°C or higher or 50°C or higher. The boiling point of the aliphatic alcohol used in the method for decomposing the polycarbonate resin (C) is preferably within the above range.

[0057] The method for decomposing a polycarbonate resin is preferably a method of reacting a polycarbonate resin (C) with an aliphatic alcohol having 1 to 3 carbon atoms at a temperature equal to or lower than the boiling point of the aliphatic alcohol. A specific example of an aliphatic alcohol having 3 carbon atoms is propanol. Since the boiling point of propanol is 97.0°C under standard conditions (1 atmosphere, 25°C), the method for decomposing a polycarbonate resin is preferably a method of reacting a polycarbonate resin (C) with methanol at a temperature equal to or lower than 97.0°C. Furthermore, the method for decomposing a polycarbonate resin is preferably a method of reacting a polycarbonate resin (C) with an aliphatic alcohol having one carbon atom at a temperature equal to or lower than the boiling point of the aliphatic alcohol having one carbon atom. Specifically, the aliphatic alcohol having one carbon atom is methanol. Since the boiling point of methanol is 64.7°C under standard conditions (1 atmosphere, 25°C), the method for decomposing a polycarbonate resin is preferably a method of reacting a polycarbonate resin (C) with methanol at a temperature equal to or lower than 64.7°C. These allow the alcoholysis of the polycarbonate resin (C) to proceed under milder reaction conditions, and the diol reaction product can also be obtained efficiently. The reaction temperature means the decomposition temperature at which the polycarbonate resin (C) is subjected to a decomposition reaction.

[0058] From the viewpoint of the balance between energy efficiency and diol yield, the decomposition reaction time is preferably 10 hours or less, more preferably 8 hours or less, even more preferably 6 hours or less, and particularly preferably 4 hours or less. The lower limit is not particularly limited, but may be, for example, 0.5 hours or more or 1 hour or more. The ratio (mol%) of the amount (mol) of catalyst to the amount (mol) of raw material is preferably 25 mol% or less, more preferably 10 mol% or less, and even more preferably 5 mol% or less. There is no particular lower limit, but it may be, for example, 0.25 mol% or more, or 0.5 mol% or more.

[0059] (7) Method for producing diol A diol production method according to one embodiment of the present disclosure (hereinafter also referred to as a diol production method) involves reacting a polycarbonate resin (C) with an aliphatic alcohol in the presence of any of the above-described alcoholysis catalysts. That is, the diol production method involves decomposing the polycarbonate resin (C) using any of the above-described alcoholysis catalysts and an aliphatic alcohol having 1 to 10 carbon atoms to obtain a diol. Therefore, the diol production method is similar in conditions to the above-described polycarbonate decomposition method. The diol is obtained by decomposing the polycarbonate resin (C) described above. The diol obtained by decomposing the polycarbonate resin (C) preferably contains at least one selected from the group consisting of aromatic diols containing an aromatic ring and aliphatic diols not containing an aromatic ring, more preferably contains an aromatic diol, and further preferably contains only an aromatic diol.

[0060] The method for producing the diol is preferably an aromatic diol. Specifically, the aromatic diol obtained by decomposition of the polycarbonate resin (C) is preferably bisphenol A (2,2-bis(4-hydroxyphenyl)propane) obtained by decomposition of poly[2,2-bis(4-hydroxyphenyl)propane]. The diol obtained by decomposition of the polycarbonate resin (C) can be purified by removing the reaction residue and catalyst by filtration or other procedures, and then by distilling off the solvent or by crystallization. The purified diol may be recrystallized to increase its purity depending on its subsequent use.

[0061] The diol production method according to one embodiment of the present disclosure is similar to the above-described polycarbonate resin decomposition method in terms of conditions, etc., and is therefore preferably a production method in which polycarbonate resin (C) is reacted with an aliphatic alcohol having 1 to 10 carbon atoms at a temperature equal to or lower than the boiling point of the aliphatic alcohol. More preferably, the diol production method is a production method in which polycarbonate resin (C) is reacted with an aliphatic alcohol having 1 carbon atom at a temperature equal to or lower than the boiling point of the aliphatic alcohol. In the diol production method of the present disclosure, the specific catalyst for alcoholysis of a polycarbonate resin described above is used, and therefore, even when the reaction is carried out at a temperature equal to or lower than the boiling point of the aliphatic alcohol used, a diol compound as a reaction product can be efficiently obtained. Furthermore, in the diol production method of the present disclosure, the reaction is carried out under reaction conditions such as at or below the boiling point of the aliphatic alcohol used, which eliminates the need for pressurized conditions, allowing for simplification of the apparatus and leading to cost reduction. The diol production method of the present disclosure is a production method for efficiently obtaining a diol, since it can proceed with alcoholysis of a polycarbonate resin under such milder reaction conditions and is excellent in the yield of the diol compound, which is the reaction product, the amount recovered per unit time, and the like.

[0062] (8) Uses of diols The solid aromatic dihydroxy compound, which is the aromatic diol recovered by the method of the present disclosure, can be reused in the production process of aromatic polycarbonate. In the melt polymerization method, the solid aromatic dihydroxy compound can be used as is. In the interfacial polymerization method, the solid aromatic dihydroxy compound can be dissolved at a desired concentration in an aqueous solution of alkali metal hydroxide and used as a raw material for polycarbonate. In this case, it is also preferable to heat a solution in which the dihydroxy compound is dissolved in an aqueous solution of alkali metal hydroxide to volatilize the remaining organic solvent.

[0063] Alternatively, the recovered diol dihydroxy compound and a new dihydroxy compound may be mixed together and used to produce a polycarbonate. In this case, the proportion of the new dihydroxy compound is preferably in the range of 5 to 95 mol% of the total hydroxy compounds. The recovered aromatic dihydroxy compound and the new aromatic dihydroxy compound may be mixed by any of the following methods: solid-solid mixture, solid-liquid mixture, and liquid-liquid mixture.

[0064] The polycarbonate obtained using the dihydroxy compound recovered by the method of the present disclosure can be used by appropriately adding modifying agents such as heat stabilizers, antioxidants, release agents (fatty acid esters, etc.), lubricants, plasticizers, antistatic agents, brighteners, ultraviolet absorbers, weather resistance agents, antibacterial agents, pigments, dyes, fillers, reinforcing agents, other polymers such as resins and rubbers, and flame retardants. As the heat stabilizer, a phosphorus-based heat stabilizer is preferably used, and the blending amount of such a heat stabilizer is preferably 0.001 to 0.1 part by weight based on 100 parts by weight of the polycarbonate. The heat stabilizer may be added to the polycarbonate either by adding it to the polycarbonate solution after the polymerization reaction or by adding it to the polycarbonate powder. The heat stabilizer may be added as it is or dissolved in a solvent.

[0065] Thus, one preferred embodiment of the present disclosure is a method for producing a polycarbonate suitable for remanufacturing optical discs from optical discs or defective products from the manufacturing process thereof. Specifically, according to the present disclosure, an optical disc or a defective product from the manufacturing process thereof, which is made of an aromatic polycarbonate (polycarbonate resin (C)), is decomposed in an aqueous solution of an alkali metal hydroxide to obtain an aqueous solution of an alkali metal salt of an aromatic dihydroxy compound that constitutes the aromatic polycarbonate. This aqueous solution is then used to produce a polycarbonate by interfacial polymerization. The polycarbonate thus produced is designated as polycarbonate (D).

[0066] The polycarbonate (D) obtained by the above-mentioned method has excellent color and thermal stability, and can therefore be suitably used as a material for optical disk substrates such as magneto-optical disks, various write-once disks, digital audio disks (so-called compact disks), optical video disks (so-called laser disks), and digital versatile disks (DVDs).

[0067] The solid aromatic dihydroxy compound, which is the diol recovered by the method of the present disclosure, can be reused in the production process of the corresponding epoxy resin. One method for reuse is to blend a curing agent with the diol. Furthermore, other epoxy compounds, curing accelerators, and other components can be appropriately blended as needed.

[0068] In the method for producing a composition containing an epoxy resin, it is preferable to use, as the curing agent, at least one selected from the group consisting of polyfunctional phenols, polyisocyanate compounds, amine compounds, acid anhydride compounds, imidazole compounds, amide compounds, cationic polymerization initiators, and organic phosphines. The epoxy resin composition obtained by the above-mentioned method can be suitably used in the fields of paints, electric and electronic materials, adhesives, fiber reinforced plastics (FRP), etc. [Example]

[0069] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples. The materials, amounts used, proportions, and processing procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present disclosure.

[0070] (1) Ligand (B) used in the examples In the examples, ligands (B-1) and (B-2) containing the following compounds were used. In the following, the notation ">98.0%" indicates the purity of each ligand (B). Furthermore, the notation "(GC)" means that the analysis was performed by gas chromatography, and the notation "(Capillary GC)" means that the analysis was performed by capillary gas chromatography.

[0071] (B-1) Ethyl 3-oxobutyrate (Tokyo Chemical Industry Co., Ltd., >98.0%) (B-2) Ethyl 3-oxo-3-phenylpropanoate (Tokyo Chemical Industry Co., Ltd., >95.0% (GC))

[0072] (2) Ligand (B) used in the comparative example In the comparative examples, ligands (B-3) and (B-4) containing the following compounds were used. (B-3) 1-Phenyl-1,3-butanedione (Tokyo Chemical Industry Co., Ltd., >98.0% (GC)) (B-4) Diethyl malonate (Fujifilm Wako Pure Chemical Industries, Ltd., 98.0+% (Capillary GC) (3) Example 1 (3-1) Preparation of rare earth complexes 20 mmol of the ligand (B-1) was dissolved in methanol under basic conditions by adding a sodium hydroxide methanol solution to obtain a ligand solution. A solution of 2 mmol of a lanthanum compound (lanthanum (III) chloride heptahydrate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) in methanol was prepared and added dropwise to the ligand solution prepared above while stirring. The resulting solid was filtered and dried to obtain a lanthanum complex (rare earth complex). The metal species of the rare earth metal (A) and the type of the ligand (B) used for the obtained rare earth complexes are shown in Table 1. The numbers of the rare earth metal (A) and the numbers of the ligand (B) are assigned in accordance with the metal species of the rare earth metal (A) and the type of the ligand (B), respectively.

[0073] (3-2) Polycarbonate resin (C) As the polycarbonate resin (C), the following aromatic polycarbonate (C-1) was prepared. C-1: Poly[2,2-bis(4-hydroxyphenyl)propane] (trade name: Polycarbonate resin, manufactured by Thermo Fisher Scientific)

[0074] (3-3) Decomposition of polycarbonate resin (C) and production of diol (3-3-1) Preparation (3-3-1-1) Production of polycarbonate resin (C) powder The aromatic polycarbonate (C-1) pellets were stirred overnight in toluene at room temperature to obtain a white dispersion of polycarbonate resin (C-1). This was filtered through a 500 μm SUS mesh, the solvent was evaporated, and the resulting mixture was powdered in a mortar. The particle size of the resulting powder was 250 μm on average.

[0075] (3-3-1-2) Catalyst The rare earth complex (B-1) prepared as described above was dried overnight under reduced pressure at room temperature.

[0076] (3-3-1-3) Fatty alcohol Methanol was refluxed with Mg / iodine and then distilled to obtain dehydrated methanol, which was then placed in activated molecular sieves 3A and allowed to stand overnight.

[0077] (3-3-2) Decomposition of polycarbonate resin (C) 0.4 mmol of the aromatic polycarbonate (C-1) powder, 0.004 mmol of the catalyst, and 4 mL of methanol were placed in a sealed reaction vessel, and the atmosphere in the system was replaced with argon. The reaction vessel was stirred in a 60°C oil bath for 2 hours, and then air-cooled to room temperature. Decane was added as an internal standard, diluted with methanol, and stirred for 5 minutes. The solution was passed through a membrane filter and analyzed by GC, and the yield of the diol compound, which was the decomposition product, was calculated. In the column "Yield of diol form" in Table 1 below, the mass of the diol form relative to the total mass of the obtained decomposition products is shown as "%" and is described as the yield.

[0078] (4) Example 2 and Comparative Examples 1 and 2 A lanthanum complex was obtained under the same conditions as in Example 1, except that the ligand (B-1) was changed to each of the ligands (B-2) to (B-4) shown in Table 1, and further, decomposition of the aromatic polycarbonate (C-1) and production of a diol were carried out. The rare earth metal species (A) and the type of ligand (B) used for the obtained rare earth complexes are shown in the table. In each of Example 2 and Comparative Examples 1 and 2, the mass of the diol relative to the total mass of the obtained decomposition products is shown in "%" in the column "Yield of diol" in Table 1, and is recorded as the yield.

[0079] [Table 1]

[0080] (5) Evaluation results The results shown in Table 1 demonstrate that Examples 1 and 2, which used the alcoholysis catalyst of the present disclosure, allowed the alcoholysis of polycarbonate resin to proceed at 60°C, which is below the boiling point of the solvent, methanol, and also allowed the diol compound, which is the reaction product, to be efficiently obtained. In Comparative Examples 1 and 2, which used catalysts that do not fall under the alcoholysis catalysts of the present disclosure, it was clear that the yield of diol was lower than that of the present disclosure.

Claims

1. A rare earth complex containing a rare earth metal (A) and a ligand (B), The ligand (B) contains a compound represented by the following general formula (1): A catalyst for alcoholysis of polycarbonate resin (C). 【Chemistry 1】 [In general formula (1), R １ and R ２ are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms, R ３ and R ４ are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms.

2. In the general formula (1), R １ is a substituted or unsubstituted benzene ring having 6 to 8 carbon atoms, R ２ is an unsubstituted alkyl group having 1 to 3 carbon atoms, R ３ and R ４ is a hydrogen atom, 2. A catalyst for alcoholysis of polycarbonate resin according to claim 1.

3. 2. The catalyst for alcoholysis of a polycarbonate resin according to claim 1, wherein the rare earth metal (A) comprises at least one metal selected from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

4. A method for decomposing a polycarbonate resin, comprising reacting the polycarbonate resin (C) with an aliphatic alcohol having 1 to 10 carbon atoms in the presence of the catalyst for alcoholysis of a polycarbonate resin according to any one of claims 1 to 3.

5. 5. The method for decomposing a polycarbonate resin according to claim 4, wherein the polycarbonate resin (C) is reacted with an aliphatic alcohol having 1 to 3 carbon atoms at a temperature equal to or lower than the boiling point of the aliphatic alcohol.

6. 5. The method for decomposing a polycarbonate resin according to claim 4, wherein the polycarbonate resin (C) is reacted with an aliphatic alcohol having one carbon atom at a temperature equal to or lower than the boiling point of the aliphatic alcohol.

7. 5. The method for decomposing a polycarbonate resin according to claim 4, wherein the polycarbonate resin (C) comprises at least one selected from the group consisting of aromatic polycarbonates (C-1) and aliphatic polycarbonates (C-2).

8. 5. The method for decomposing a polycarbonate resin according to claim 4, wherein the polycarbonate resin (C) contains an aromatic polycarbonate (C-1).

9. A method for producing a diol, comprising reacting the polycarbonate resin (C) with an aliphatic alcohol in the presence of the catalyst for alcoholysis of a polycarbonate resin according to any one of claims 1 to 3.

10. The method for producing a diol according to claim 9 , wherein the polycarbonate resin (C) is reacted with an aliphatic alcohol having one carbon atom at a temperature equal to or lower than the boiling point of the aliphatic alcohol.

11. The method for producing a diol according to claim 9, wherein the polycarbonate resin (C) contains an aromatic polycarbonate (C-1).

12. The method for producing a diol according to claim 9, wherein an aromatic diol is produced.

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