Method for producing aromatic polysulfone

Abstract

The method for producing an aromatic polysulfone has a step for reacting an aromatic polysulfone precursor with a compound represented by (A). The aromatic polysulfone precursor has a repeating unit including a structure represented by formula (S-1) in the main chain and has a halogen atom at a main chain end. The step is carried out in an aprotic organic solvent in the presence of an alkali metal salt and a phase transfer catalyst. -ph1-SO2-ph2-O- … (S-1) [ph1, ph2: optionally substituted phenylene group] (Ra)x-Ar-OM … (A) [Ar: optionally substituted aromatic hydrocarbon group. Ra: one or more polar groups selected from the group consisting of acidic groups having a pKa equal to or less than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom. x: integer of 1 or more. M: hydrogen atom or monovalent cation ]

Description

Method for producing aromatic polysulfone

[0001] The present invention relates to a method for producing aromatic polysulfone. This application claims priority to Japanese Patent Application No. 2023-205613, filed December 5, 2023, the contents of which are incorporated herein by reference.

[0002] Aromatic polysulfone has excellent properties such as heat resistance, mechanical properties, electrical properties, and hot water resistance, and is therefore used in a variety of applications in the fields of electrical and electronics, machinery, automobiles, aircraft, medical and food industries, etc.

[0003] Depending on the application, hydrophilized aromatic polysulfone is required. Specific examples of such hydrophilized aromatic polysulfone include aromatic polysulfone having a polar group.

[0004] Patent Document 1 proposes an internal pressure type hollow fiber NF membrane using sulfonated polyethersulfone, which is a hydrophilized aromatic polysulfone, and discloses an internal pressure type hollow fiber NF membrane made of a mixture containing sulfonated polyethersulfone and polyethersulfone.

[0005] JP 2013-215640 A

[0006] When aromatic polysulfone is used as a material for forming a separation membrane, the separation membrane formed from the aromatic polysulfone is required to have high water permeability. High water permeability means that a large amount of water permeates the membrane per unit time under a predetermined pressure. In the above-mentioned Patent Document 1, a hollow fiber NF membrane with high water permeability is realized by using sulfonated polyethersulfone in which sulfonic acid groups are introduced as polar groups.

[0007] The sulfonated polyethersulfone used in Patent Document 1 is produced by sulfonating polyethersulfone using sulfuric acid or chlorosulfonic acid. However, reactions using such strong acids are limited in the equipment available for production. Furthermore, the reaction generates a large amount of salt during the neutralization reaction in the post-treatment. Therefore, a simpler method for producing polysulfone having polar groups such as sulfonic groups introduced therein has been desired.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing aromatic polysulfone that enables easy production of aromatic polysulfone having polar groups introduced therein.

[0009] In order to solve the above problems, one aspect of the present invention includes the following aspects.

[0010] [1] A method for producing an aromatic polysulfone, comprising a step of reacting an aromatic polysulfone precursor with at least one compound represented by the following formula (A), wherein the aromatic polysulfone precursor has a repeating unit containing a structure represented by the following general formula (S-1) in its main chain and has a halogen atom at the end of the main chain, and the step is carried out in an aprotic organic solvent in the presence of at least one alkali metal salt and at least one phase transfer catalyst. １ -SO ２ -ph ２ -O- ... (S-1) [In formula (S-1), ph １ and ph ２ each independently represents a phenylene group which may have a substituent.] (Ra) ｘ -Ar-OM (A) [In formula (A), Ar represents an aromatic hydrocarbon group which may have a substituent. Ra represents one or more polar groups selected from acidic groups having a pKa equal to or lower than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom. x represents an integer of 1 or greater. M represents a hydrogen atom or a monovalent cation.]

[0011] [2] The method for producing an aromatic polysulfone according to [1], wherein the amount of the phase transfer catalyst is 10 mol % or more and 1000 mol % or less relative to the alkali metal salt.

[0012] [3] The method for producing aromatic polysulfone according to [1] or [2], wherein the reaction temperature in the step is 130°C or higher but lower than 200°C.

[0013] [4] The method for producing aromatic polysulfone according to any one of [1] to [3], wherein the phase transfer catalyst is 18-crown-6-ether.

[0014] [5] The method for producing an aromatic polysulfone according to any one of [1] to [4], wherein the alkali metal salt is a potassium salt.

[0015] [6] The method for producing an aromatic polysulfone according to any one of [1] to [5], wherein Ra is a sulfonic acid group, a salt of a sulfonic acid group, or an amino group.

[0016] [7] The method for producing an aromatic polysulfone according to any one of [1] to [6], wherein Ra is a sulfonic acid group or a salt of a sulfonic acid group.

[0017] According to the present invention, it is possible to provide a method for producing aromatic polysulfone that allows easy production of aromatic polysulfone into which polar groups have been introduced.

[0018] In the following description, when a numerical range is described as, for example, "A to B," it means "A or more and B or less," including the lower limit A and the upper limit B.

[0019] <<Method for Producing Aromatic Polysulfone>> The method for producing aromatic polysulfone of this embodiment includes a step of reacting an aromatic polysulfone precursor having a repeating unit containing a structure represented by the following general formula (S-1) in its main chain and having a halogen atom at the end of the main chain with at least one compound represented by the following formula (A). This reaction step is carried out in an aprotic organic solvent in the presence of at least one alkali metal salt and at least one phase transfer catalyst. -ph １ -SO ２ -ph ２ -O- ... (S-1) [In formula (S-1), ph １ and ph ２ each independently represents a phenylene group which may have a substituent.] (Ra)ｘ -Ar-OM (A) [In formula (A), Ar represents an aromatic hydrocarbon group which may have a substituent. Ra represents one or more polar groups selected from acidic groups having a pKa equal to or lower than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom. x represents an integer of 1 or greater. M represents a hydrogen atom or a monovalent cation.]

[0020] The structure of the resulting aromatic polysulfone will be described below, followed by a detailed description of the method for producing the aromatic polysulfone of this embodiment.

[0021] [Aromatic Polysulfone] The aromatic polysulfone has, at the main chain terminal, one or more polar groups selected from acidic groups having a pKa equal to or lower than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom. In the following description, the aromatic hydrocarbon group having one or more polar groups selected from acidic groups having a pKa equal to or lower than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom may be referred to as "FG."

[0022] In the following description, the "acidic group having a pKa equal to or lower than the pKa of a carboxy group," the "salt of an acidic group having a pKa equal to or lower than the pKa of a carboxy group," and the "functional group containing a nitrogen atom" may be collectively referred to as "Ra" used in the above formula (A).

[0023] (Structure 1 of the Main Chain) The aromatic polysulfone has a repeating unit containing the structure represented by the above formula (S-1) in the main chain. １ and ph ２ The phenylene group in may be a p-phenylene group, an m-phenylene group, or an o-phenylene group, but is preferably a p-phenylene group.

[0024] Examples of the substituent that the phenylene group may have include an alkyl group, an aryl group, etc. The number of substituents that the phenylene group has is each independently 0 to 4, preferably 0 to 2, more preferably 0 to 1, and even more preferably 0. When the phenylene group has multiple substituents, the multiple substituents may be the same or different.

[0025] The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. Specific examples of suitable alkyl groups include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, and an n-decyl group.

[0026] The aryl group may be an aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Specific preferred examples include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, and a 2-naphthyl group.

[0027] More specifically, the aromatic polysulfone has a main chain structure represented by the following formula (S-1-1): In the repeating unit of the main chain structure represented by the following formula (S-1-1), the remainder excluding X corresponds to the structure represented by the above general formula (S-1).

[0028] [In the formula, R １ and R ２ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. n1 and n2 are each independently an integer of 0 to 4. When n1 or n2 is 2 or more, a plurality of R １ and R ２ may be the same or different. X is a single bond or a group derived from bisphenol or biphenol. n is an integer of 1 or more.

[0029] The group derived from bisphenol in X is a divalent group obtained by removing hydrogen atoms from two hydroxy groups of bisphenol. Specific examples include groups derived from bisphenol A (2,2-bis(4-hydroxyphenyl)propane), bisphenol AF (2,2-bis(4-hydroxyphenyl)hexafluoropropane), bis(4-hydroxyphenyl)sulfide, bis(4-hydroxy-3-methylphenyl)sulfide, and bis(4-hydroxyphenyl)ether. Of these, the group derived from bisphenol A is preferred.

[0030] Of X, the group derived from biphenol is a divalent group obtained by removing hydrogen atoms from two hydroxy groups of biphenol. Specific examples include groups derived from 4,4'-biphenol (4,4'-dihydroxybiphenyl), 2,2'-dihydroxybiphenyl, 3,5,3',5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-diphenyl-4,4'-dihydroxybiphenyl, and 4,4'-dihydroxy-p-quaterphenyl. Of these, the group derived from 4,4'-biphenol is preferred.

[0031] X is preferably a single bond.

[0032] n is preferably 5 to 600.

[0033] (Main Chain Structure 2) The aromatic polysulfone may have a repeating unit containing a structure represented by the following formula (S-2) or a structure represented by the following formula (S-3) in the main chain. ３ -R-ph ４ -O-...(S-2) -(ph ５ ) ｎ -O-...(S-3) [In formula (S-2), ph ３ and ph ４ are each independently a phenylene group which may have a substituent. R is an alkylidene group, an oxygen atom, or a sulfur atom. In formula (S-3), ph ５ is a phenylene group which may have a substituent. n is an integer of 1 to 3. When n is 2 or more, a plurality of Ph ５may be the same or different from each other.

[0034] ph ３ , ph ４ and ph ５ are the ph in formula (S-1), respectively. １ and ph ２ Examples of the phenylene group include the same groups as the optionally substituted phenylene group in the above formula (1).

[0035] The alkylidene group is preferably an alkylidene group having 1 to 5 carbon atoms, and examples thereof include a methylene group, an ethylidene group, an isopropylidene group, and a 1-butylidene group.

[0036] In formula (S-3), n is preferably 1 or 2.

[0037] (Structure of Main Chain Terminal) The aromatic polysulfone of this embodiment has the above-mentioned FG at the main chain terminal. In this specification, the term "polar group" refers to a group containing one or more heteroatoms. Specifically, the term "polar group" refers to one or more groups selected from the group consisting of "an acidic group having a pKa equal to or lower than the pKa of a carboxy group," "a salt of an acidic group having a pKa equal to or lower than the pKa of a carboxy group," and "a functional group containing a nitrogen atom."

[0038] In this specification, the term "an acidic group having a pKa value equal to or lower than the pKa value of a carboxy group" refers to an acidic group having such a property that, when a carboxy group of a compound having a carboxy group is converted into the acidic group, the pKa value of the compound having the acidic group becomes equal to or lower than the pKa value of the compound having a carboxy group.

[0039] Specific examples of the "acidic group having a pKa value equal to or lower than the pKa value of the carboxy group" in aromatic polysulfone include a carboxy group (-COOH), a sulfonic acid group (-SO ２ OH), sulfinic acid group (-SO ２ H), phosphate group (H ２ P.O. ４ Among these, a sulfonic acid group is preferred.

[0040] Furthermore, in this specification, the term "salt of an acidic group (salt of an acidic group having a pKa equal to or lower than the pKa of a carboxy group)" refers to a salt of the above-mentioned acidic group and a base (an inorganic base or an organic base), i.e., a group in which the above-mentioned acidic group and a base form a salt.

[0041] Examples of salts of an acidic group and an inorganic base include alkali metal salts such as sodium salts and potassium salts, and ammonium salts. Examples of salts of an acidic group and an organic base include imidazolium salts and pyridinium salts.

[0042] Examples of the imidazolium salt include N,N'-dialkylimidazolium salts such as 1-methylimidazolium salt, 1-ethyl-3-methylimidazolium salt, 1-propyl-3-methylimidazolium salt, 1-methyl-3-octylimidazolium salt, 1-decyl-3-methylimidazolium salt, 1-dodecyl-3-methylimidazolium salt, 1-methyl-3-dodecylimidazolium salt, 1-tetradecyl-3-methylimidazolium salt, 1-methyl-3-tetradecylimidazolium salt, 1-hexadecyl-3-methylimidazolium salt, 1-hexadecyl-4-methylimidazolium salt, 1-methyl-3-hexadecylimidazolium salt, and 1-dodecyl-2-methyl-3-benzylimidazolium salt.

[0043] Examples of pyridinium salts include N-alkylpyridinium salts such as 1-methylpyridinium salt, 1-butyl-4-methylpyridinium salt, 1-laurylpyridinium salt, 1-tetradecylpyridinium salt, 1-hexadecylpyridinium salt, 1-tetradecyl-4-methylpyridinium salt, and 1-hexadecyl-4-methylpyridinium salt.

[0044] The "salt of an acidic group" in the aromatic polysulfone is preferably a group consisting of an alkali metal salt, imidazolium salt, or pyridinium salt of a carboxy group, sulfonic acid group, sulfinic acid group, or phosphate group, more preferably a group consisting of an alkali metal salt of a sulfonic acid group, sulfinic acid group, or phosphate group, and even more preferably a group consisting of an alkali metal salt of a sulfonic acid group.

[0045] The "salt of an acidic group" includes a sodium sulfonate group (-SO ２ ONa) or potassium sulfonate group (-SO ２ OK) is preferred.

[0046] The "functional group containing a nitrogen atom" in aromatic polysulfone specifically includes an amino group (-NH ２ ) etc.

[0047] The aromatic polysulfone may have one or more FGs, and may have one or more of the above-mentioned acidic groups, salts of acidic groups, and nitrogen-containing functional groups.

[0048] The main chain terminal of the aromatic polysulfone is more preferably a terminal unit represented by the following formula (Se-1): (Ra) ｘ -Ar-O- (Se-1) [wherein Ar is an aromatic hydrocarbon group which may have a substituent; Ra is one or more polar groups selected from the group consisting of acidic groups having a pKa equal to or lower than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom; and x is an integer of 1 or greater.]

[0049] The aromatic hydrocarbon group represented by Ar has at least one aromatic ring. The aromatic ring may be monocyclic or polycyclic. The aromatic ring may also be an aromatic heterocyclic ring.

[0050] Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring, with a benzene ring or a naphthalene ring being preferred.

[0051] The substituents that Ar may have are the same as those in the above-mentioned ph １ , ph ２ Examples of the substituents include the same alkyl groups and aryl groups as those which may be contained in the group.

[0052] Ra in formula (Se-1) is the same as Ra in the above formula (A). Ra is preferably a sulfonic acid group or a salt of a sulfonic acid group.

[0053] The bonding position of Ra bonded to Ar is not particularly limited. When Ar is a phenylene group, Ra is preferably at the meta or para position relative to the oxygen atom bonded to the phenylene group.

[0054] (Amount of FG) In this embodiment, the amount of FG in the aromatic polysulfone is determined as the amount of FG per 100 repeating units forming the main chain (FG ratio; hereinafter, sometimes referred to as "FG amount").

[0055] The amount of FG at the main chain end is determined by the amount of the aromatic polysulfone. １ It is calculated from the peak area of ​​H-NMR. Specific calculation methods are as follows (i) to (v).

[0056] (i) Aromatic polysulfone １ H-NMR measurement was carried out, and the obtained １ The peak area A of hydrogen atoms contained in the repeating units of the main chain of the aromatic polysulfone is determined from the H-NMR spectrum. As the peak area A, the peak area of ​​all hydrogen atoms contained in the repeating unit (i-1) may be determined, or only the peak area of ​​easily attributable hydrogen atoms among the hydrogen atoms contained in the repeating unit (i-2) may be determined.

[0057] In the case of (i-2), for example, when the aromatic ring of the repeating unit is unsubstituted, the peak area of ​​the hydrogen atom at the α-position of the sulfonyl group can be taken as the peak area A. Furthermore, when the hydrogen atom of the aromatic ring of the repeating unit is substituted with a methyl group and the aromatic polysulfone as a whole has no other alkyl groups, the peak area of ​​the hydrogen atom of the methyl group can be taken as the peak area A.

[0058] (ii) The peak area A is divided by the number of hydrogen atoms bonded to the aromatic ring of the main chain to calculate a value corresponding to the number of repeating units (number of units). For example, if the peak area A is the peak area attributable to four hydrogen atoms bonded to the aromatic ring of the main chain, the peak area A is divided by 4. If the hydrogen atoms of the aromatic ring of the main chain are substituted with methyl groups and the peak area A is the peak area attributable to the hydrogen atoms of the methyl groups, the peak area A is divided by "3 × the number of methyl groups bonded to the aromatic ring."

[0059] (iii) the above １ From the H-NMR spectrum, the peak area B assigned to the α hydrogen of Ra in the aromatic ring at the end of the main chain of the aromatic polysulfone is determined.

[0060] (iv) The peak area B is divided by the number of α-hydrogens to calculate a value corresponding to the number of aromatic rings to which Ra is bonded. For example, if the peak area B is the peak area assigned to two α-hydrogens, the peak area B is divided by 2.

[0061] (v) The amount of FG per 100 repeating units forming the main chain of the aromatic polysulfone can be calculated by dividing the value obtained in (iv) by the value obtained in (ii) and then multiplying the result by 100 (units).

[0062] １ The measurement solvent in the H-NMR measurement may be any heavy solvent that can dissolve aromatic polysulfone, and deuterated dimethyl sulfoxide is preferred. １ The measurement conditions for H-NMR include the following: In the NMR sample, the concentration of the aromatic polysulfone to be measured is, for example, 80 mg / mL. (Measurement conditions) Measurement device: ECZ400S (manufactured by JEOL) Static magnetic field strength: 9.4 Tesla (resonance frequency: 400 MHz ( １ H) Spinning: 15 Hz Repetition time: 7.2 seconds Number of accumulations: 64 Temperature: room temperature Internal standard substance: dimethyl sulfoxide

[0063] For example, when the main chain of an aromatic polysulfone is composed of repeating units represented by the following formula (mc-1) and the main chain terminal has a structure represented by the following formula (e-1), the FG amount per 100 repeating units of the aromatic polysulfone is calculated by the calculation method shown below.

[0064] ​In the following formula, Xp is the peak area assigned to the "hydrogen atom at the α-position of the sulfonyl group" (hydrogen atom Hx) in formula (mc-1). Yp is the peak area assigned to the "hydrogen atom at the α-position of the sulfonate group" (hydrogen atom Hy) in formula (e-1) (aromatic ring at the end of the main chain). FG amount = [(Yp / 2) / (Xp / 4)] x 100 = Yp / Xp x 200

[0065]

[0066]

[0067] In the above example, the polar group at the end of the main chain is a sulfonate group, but the same can be said for the case where the polar group at the end of the main chain is an amino group.

[0068] When the main chain terminal has a structure represented by the following formula (e-2), the FG amount per 100 repeating units of the aromatic polysulfone is calculated by the following calculation method: FG amount = [Yp / (Xp / 4)] × 100 = Yp / Xp × 400

[0069]

[0070] [Method for Producing Aromatic Polysulfone] In this embodiment, the aromatic polysulfone is produced by reacting an aromatic polysulfone precursor with a compound having FG in the presence of at least one alkali metal salt and at least one phase transfer catalyst.

[0071] One embodiment of the method for producing aromatic polysulfone includes the steps of: preparing an aromatic polysulfone precursor having a halogen atom at the main chain terminal (step (i)); and reacting the aromatic polysulfone precursor with a compound having FG in the presence of at least one alkali metal salt and at least one phase transfer catalyst to produce an aromatic polysulfone having FG at the main chain terminal (step (ii)).

[0072] (Step (i)) As described above, the aromatic polysulfone precursor has a repeating unit containing a structure represented by the following general formula (S-1) in its main chain and has a halogen atom at the end of the main chain: １ -SO ２ -ph ２ -O-...(S-1)

[0073] The aromatic polysulfone precursor may be one synthesized by the method described below, or may be a commercially available product.

[0074] Commercially available aromatic polysulfone precursors include, for example, Sumikaexcel (registered trademark) PES 3600P, 4800P, and 5900P (all polyethersulfones, all manufactured by Sumitomo Chemical Co., Ltd.).

[0075] The weight average molecular weight of the aromatic polysulfone precursor is preferably 1,000 to 200,000, more preferably 8,000 to 150,000, and even more preferably 10,000 to 100,000.

[0076] The weight-average molecular weight (Mw) can be determined by gel permeation chromatography (GPC). Specifically, the weight-average molecular weight of the aromatic polysulfone precursor refers to a value calculated in terms of standard polystyrene based on a calibration curve obtained by measuring the molecular weight of standard polystyrene.

[0077] (Method for Producing Aromatic Polysulfone Precursor) The aromatic polysulfone precursor can be produced by using a halogenoaromatic sulfone compound having two or three halogen atoms bonded thereto, a dihydroxyaromatic compound, or the like as a monomer, and subjecting these monomers to a polycondensation reaction in an organic solvent in the presence of a base.

[0078] (Monomer) A halogenoaromatic sulfone compound is a compound having an aromatic ring, a sulfonyl group, and two or three halogen atoms bonded to the aromatic ring in one molecule. A dihydroxyaromatic compound is a compound having an aromatic ring and two hydroxy groups bonded to the aromatic ring in one molecule. The halogenoaromatic sulfone compound and the dihydroxyaromatic compound correspond to the repeating units constituting the aromatic polysulfone precursor.

[0079] The aromatic polysulfone precursor can be produced by using a compound represented by the following formula (mx-1) as the halogeno aromatic sulfone compound and a compound represented by the following formula (my-1) as the dihydroxy aromatic compound. １ -ph １ -SO ２ -ph ２ -(X ２ ) ｍ ...(mx-1) HO-ph １ -SO ２ -ph ２ -OH...(my-1) [in formula (mx-1), ph １ and ph ２ are each independently a phenylene group which may have a substituent. １ and X ２ are each independently a halogen atom, and m is 1 or 2. In formula (my-1), ph １ and ph ２ are each independently a phenylene group which may have a substituent.

[0080] Ph in formulas (mx-1) and (my-1) １ and ph ２ is the ph in the above general formula (S-1). １ and ph ２ is the same as

[0081] In formula (mx-1), X １ and X ２ are each independently a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a chlorine atom is preferred.

[0082] Examples of the compound represented by formula (mx-1) include 4,4'-dichlorodiphenyl sulfone, 4,4'-difluorodiphenyl sulfone, and 4-chlorophenyl-3',4'-dichlorophenyl sulfone.

[0083] Examples of the compound represented by formula (my-1) include bis(4-hydroxyphenyl)sulfone, bis(4-hydroxy-3,5-dimethylphenyl)sulfone, and bis(4-hydroxy-3-phenylphenyl)sulfone.

[0084] When the aromatic polysulfone precursor further has a repeating unit containing the structure represented by the above formula (S-2), a compound represented by the following formula (my-2) is used as the dihydroxy aromatic compound: ３ -R-ph ４ -OH...(my-2) [in formula (my-2), ph ３ and ph ４ are each independently a phenylene group which may have a substituent; R is an alkylidene group, an oxygen atom, or a sulfur atom.

[0085] In formula (my-2), ph ３ , ph ４ and R is the ph in the above formula (S-2). ３ , ph ４ and R, respectively.

[0086] Examples of the compound represented by formula (my-2) include bisphenol A: (2,2-bis(4-hydroxyphenyl)propane), bisphenol AF: 2,2-bis(4-hydroxyphenyl)hexafluoropropane, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxy-3-methylphenyl)sulfide, and bis(4-hydroxyphenyl)ether.

[0087] When the aromatic polysulfone precursor further has a repeating unit containing the structure represented by the above formula (S-3), a compound represented by the following formula (my-3) is used as the dihydroxy aromatic compound. ５ ) ｎ -OH...(my-3) [in formula (my-3), ph ５ is a phenylene group which may have a substituent. n is an integer of 1 to 3. When n is 2 or more, multiple ph5s may be the same or different.

[0088] In formula (my-3), ph ５ and n is the ph in the above formula (S-3). ５ and n, respectively.

[0089] Examples of the compound represented by formula (my-3) include hydroquinone, resorcinol, catechol, phenylhydroquinone, 4,4'-dihydroxybiphenyl, 2,2'-dihydroxybiphenyl, 3,5,3',5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,2'-diphenyl-4,4'-dihydroxybiphenyl, and 4,4'''-dihydroxy-p-quaterphenyl.

[0090] In the production of an aromatic polysulfone precursor, either one type of halogeno aromatic sulfone compound or one type of dihydroxy aromatic compound may be used alone or in combination, depending on the type of aromatic polysulfone desired.

[0091] (Base, Organic Solvent) The polycondensation of a halogenoaromatic sulfone compound and a dihydroxyaromatic compound is preferably carried out using an alkali metal carbonate or an alkali metal hydroxide as a base. The polycondensation is also preferably carried out in an organic solvent. It is more preferable that the polycondensation is carried out using an alkali metal carbonate or an alkali metal hydroxide as a base and in an organic solvent.

[0092] Examples of alkali metal hydroxides include potassium hydroxide, sodium hydroxide, cesium hydroxide, etc. The hydroxides may be anhydrous or hydrated, or may be a mixture thereof.

[0093] The alkali metal carbonate may be an alkali carbonate (an alkali metal carbonate), an alkali bicarbonate (an alkali metal hydrogen carbonate), or a mixture thereof.

[0094] Examples of alkali carbonates include sodium carbonate, potassium carbonate, cesium carbonate, etc. Examples of alkali bicarbonates include sodium bicarbonate (sodium hydrogen carbonate), potassium bicarbonate (potassium hydrogen carbonate), cesium bicarbonate (cesium hydrogen carbonate), etc.

[0095] The organic solvent is preferably an aprotic polar solvent, and the boiling point of the organic solvent is preferably 100°C or higher and 400°C or lower, and more preferably 100°C or higher and 350°C or lower.

[0096] Examples of such organic solvents include sulfoxides such as dimethyl sulfoxide; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfones such as sulfolane (1,1-dioxothiane), dimethyl sulfone, diethyl sulfone, diisopropyl sulfone, and diphenyl sulfone; and 1,3-dimethyl-2-imidazolidinone and 1,3-diethyl-2-imidazolidinone.

[0097] The organic solvent may be used alone or in combination of two or more kinds.

[0098] The polycondensation reaction temperature is preferably 180° C. or higher and 400° C. or lower, and the reaction time is preferably 4 to 10 hours.

[0099] (Step (ii)) In this embodiment, a compound represented by the following formula (A) is used as a compound having FG (hereinafter, sometimes referred to as an end capping agent): (Ra) ｘ -Ar-(OM) ｙ ...(A) [In formula (A), Ar represents an aromatic hydrocarbon group which may have a substituent. Ra represents one or more polar groups selected from the group consisting of acidic groups having a pKa equal to or lower than the pKa of a carboxy group, salts of the acidic groups, and functional groups containing a nitrogen atom. x represents an integer of 1 or greater. y represents 1 or 2. M represents a hydrogen atom or a monovalent cation.]

[0100] Ra and Ar in formula (A) are the same as Ra and Ar in formula (Se-1) above. Ra is preferably a sulfonic acid group, a salt of a sulfonic acid group, or an amino group.

[0101] Examples of the cation in M ​​include alkali metal ions and cations of organic bases such as imidazolium ions and pyridinium ions.

[0102] The end-capping agent is a compound represented by formula (A) and is not particularly limited as long as it can introduce FG into the main chain terminal of the aromatic polysulfone precursor. Examples of the end-capping agent include the following compounds depending on the value of Ra (x in formula (A)) possessed by the end-capping agent:

[0103] End-capping agents having one Ra 4-hydroxybenzoic acid and its alkali metal salts 4-hydroxybenzenesulfonic acid and its alkali metal salts 3-hydroxybenzenesulfonic acid and its alkali metal salts 4-hydroxybenzenesulfinic acid and its alkali metal salts 3-hydroxybenzenesulfinic acid and its alkali metal salts (4-hydroxyphenyl)phosphonic acid and its alkali metal salts (3-hydroxyphenyl)phosphonic acid and its alkali metal salts 4-aminophenol 3-aminophenol

[0104] End-capping agents having two Ra 2-hydroxy-6,8-naphthalenedisulfonic acid and its alkali metal salts 3-hydroxy-2,7-naphthalenedisulfonic acid and its alkali metal salts 3-hydroxy-2,6-naphthalenedisulfonic acid and its alkali metal salts 5-hydroxy-1,3-benzenedisulfonic acid and its alkali metal salts 6,8-dihydroxy-1,3-pyrenedisulfonic acid and its salts 3,6-dihydroxy-2,7-naphthalenedisulfonic acid and its salts 2,2'-dihydroxy-1,1'-binaphthyl-6,6'-disulfonic acid and its salts 4,5-dihydroxy-1,3-benzenedisulfonic acid and its salts 2,4-diaminophenol 2,5-diaminophenol

[0105] End-capping agents having three Ra: 7-hydroxy-1,3,6-naphthalenetrisulfonic acid and its alkali metal salts

[0106] (Aprotic Organic Solvent) Examples of the aprotic organic solvent used in the production of aromatic polysulfone include the aprotic polar solvents exemplified above in (Method for producing aromatic polysulfone precursor).

[0107] (Alkali Metal Salt) Examples of the alkali metal salt used in the production of aromatic polysulfone include the bases exemplified above in (Method for producing aromatic polysulfone precursor). As the alkali metal salt, sodium salt, potassium salt, and cesium salt are preferred, and potassium salt is more preferred.

[0108] (Phase Transfer Catalyst) In the method for producing aromatic polysulfone according to the present embodiment, a phase transfer catalyst is used during the reaction between the aromatic polysulfone precursor and the end-capping agent. The inventors consider the effect of the phase transfer catalyst as follows.

[0109] In the reaction between the aromatic polysulfone precursor and the end capping agent, it is believed that a reaction occurs between the aromatic polysulfone precursor and an anionic species of the end capping agent, which is generated by the reaction of the hydroxyl group of the end capping agent with an alkali metal salt, or an anionic species possessed by the end capping agent.

[0110] In this case, if the reactivity of the end-capping agent is low, it is thought that the generation of anionic species and the reaction between the anionic species and the aromatic polysulfone precursor are difficult to occur, and the overall reaction does not proceed easily. While it is conceivable to carry out the reaction at a high reaction temperature as a means of accelerating the reaction, this increases the energy consumption during the reaction and is disadvantageous in terms of production efficiency.

[0111] In contrast, in the method for producing aromatic polysulfone of this embodiment, a phase transfer catalyst is used to increase the reactivity of the end-capping agent, which is difficult to react with. According to the method for producing aromatic polysulfone of this embodiment, the aromatic polysulfone precursor and the end-capping agent can be reacted at a relatively low temperature compared to when a phase transfer catalyst is not used, thereby reducing energy consumption during the reaction. Furthermore, because the reaction is carried out at a relatively low temperature, there are more options for the organic solvent used in the reaction and the type of heat medium used to heat the reactor, thereby increasing the degree of freedom during production.

[0112] Examples of the phase transfer catalyst include quaternary ammonium salts, crown ethers, and phosphonium compounds. These phase transfer catalysts may be used alone or in combination of two or more.

[0113] (Quaternary Ammonium Salt) The quaternary ammonium salt is not particularly limited, but preferred are: tetrabutylammonium salts such as tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium 2-ethylhexanoate, tetrabutylammonium hydrogensulfate, tetrabutylammonium chloride, tetrabutylammonium fluoride trihydrate, tetrabutylammonium nitrate, tetrabutylammonium nitrite, tetrabutylammonium acetate, and tetrabutylammonium triiodide; tetraethylammonium salts such as tetraethylammonium bromide, tetraethylammonium chloride, and tetraethylammonium fluoride dihydrate; tetrapropylammonium salts such as tetrapropylammonium bromide and tetrapropylammonium chloride; tetramethylammonium salts such as tetramethylammonium chloride; benzyltriethylammonium salts such as benzyltriethylammonium chloride and benzyltriethylammonium bromide; benzyltrimethylammonium salts such as benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, and benzyltrimethylammonium dichloroiodate; The ammonium salt is at least one selected from the group consisting of benzyltributylammonium salts such as benzyltributylammonium chloride and benzyltributylammonium bromide, methyltributylammonium salts such as methyltributylammonium chloride and methyltributylammonium bromide, methyltriethylammonium salts such as methyltriethylammonium chloride and methyltriethylammonium bromide, and phenyltrimethylammonium salts such as phenyltrimethylammonium chloride.

[0114] The quaternary ammonium salt may also be an ammonium salt having a linear alkyl group having more than 8 carbon atoms. Examples of such quaternary ammonium salts include: behenyl group (22 carbon atoms): behentrimonium chloride (behenyltrimethylammonium chloride), cetyl group (16 carbon atoms): cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, cetyltrimethylammonium hydrogen sulfate, cetalkonium chloride (benzylcetyldimethylammonium chloride), cetalkonium bromide (benzylcetyldimethylammonium bromide), cetyldimethylethylammonium bromide, cetyl group (14 carbon atoms): cetrimide (myristyltrimethylammonium bromide), decyl group (10 carbon atoms): didecyldimethylammonium chloride, dodecyl group (12 carbon atoms): dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, Octyl group (carbon number: 8): At least one selected from the group consisting of methyltrioctylammonium chloride, tetra-n-octylammonium bromide, trimethyl-n-octylammonium bromide, and trioctylmethylammonium bromide is preferred.

[0115] Among these, tetrabutylammonium salts are preferred because they are easily available, and examples thereof include tetrabutylammonium chloride.

[0116] (Crown Ether) There is no particular limitation on the crown ether, and it is represented by the general structural formula (-CH ２ -CH ２ -O-) ｎ (n is an integer), a thiacrown ether in which some or all of the oxygen atoms (—O—) in the ether bonds constituting the crown ether ring have been substituted with sulfur atoms (—S—), or an azacrown ether in which some or all of the ether bonds have been substituted with —NR— (R is a substituent) or the like.

[0117] The crown ether may be modified or may be an unmodified crown ether in the narrow sense. When the crown ether is modified, the methylene chain of the general structural formula may have a substituent, or the methylene chain may be fused to a ring.

[0118] The crown ether is preferably 4'-acetylbenzo-15-crown-5-ether, 4'-acetylbenzo-18-crown-6-ether, 4'-aminobenzo-15-crown-5-ether, 1-aza-12-crown-4-ether, 1-aza-15-crown-5-ether, 1-aza-18-crown-6-ether, benzo-12-crown-4-ether, benzo-15-crown-5-ether, benzo-18-crown-6-ether, bis(1,4-phenylene)-34-crown-10-ether, 4'-bromobenzo-15-crown-5-ether, 4'-bromobenzo-18-crown-6-ether, 4'-carboxybenzo-15-crown-5-ether), 4'-carboxybenzo-18-crown-6-ether, 15-crown-4 [4-(2,4-dinitrophenylazo)phenol], 18-crown-5 [4-(2,4-dinitrophenylazo)phenol], 12-crown 4-ether, 15-crown 5-ether, 18-crown 6-ether, 24-crown 8-ether, 4,10-diaza-12-crown 4-ether, 4,10-diaza-15-crown 5-ether, 4,13-diaza-18-crown 6-ether, dibenzo-15-crown 5-ether, dibenzo-18-crown 6-ether, dibenzo-21-crown 7-ether, dibenzo-24-crown 8-ether, dibenzo-30-crown 10-ether, N,N'-dibenzyl-4,13-diaza-18-crown 6-ether, dicyclohexano-18-crown 6-ether, 4'-formylbenzo-15-crown 5-ether, 4'-formylbenzo-18-crown 6-ether, 1,4,7,10,13,16-hexaazacyclooctadecane, 1,4,7,10,13,16-hexaazacyclooctadecane hexahydrochloride, 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane, 2-(hydroxymethyl)-12-crown-4-ether, 2-(hydroxymethyl)-15-crown-5-ether, 2-(hydroxymethyl)-18-crown-6-ether, 4'-methoxycarbonylbenzo-15-crown-5-ether, 4'-nitrobenzo-15-crown-5-ether, 4'-nitrobenzo-18-crown-6-ether, N-phenylaza-15-crown-5-ether, 1,4,7,10-tetraazacyclododecane, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, 1,4,7,10-tetraazacyclododecane tetrahydrochloride, 1,4,8,12-tetraazacyclopentadecane, 1,4,8,11-tetraazacyclotetradecane, 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane, tetraethyl-1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetate, 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, 1,4,8,11-tetrathiacyclotetradecane, 1,5,9-triazacyclododecane, 1,4,7-triazacyclononane, 1,4,7-triazacyclononane trihydrochloride, tri-tert-butyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate, tri-tert-butyl-1,4,7,10-tetraazacyclododecane-1,4,7-triacetate, 1,4,7-trimethyl-1,4,7-triazacyclononane (NaHCO, ３ stabilized), 1,4,7-trithiacyclononane, and

[0119] More preferred crown ethers include 18-crown 6-ether, 4,13-diaza-18-crown 6-ether, 15-crown 5-ether, and 24-crown 8-ether. It is preferable to use a crown ether having a ring of an appropriate size depending on the ionic radius of the metal ion constituting the alkali metal salt used. When a potassium salt is used as the alkali metal salt, 18-crown 6-ether is preferred.

[0120] (Phosphonium Compound) Examples of the phosphonium compound include quaternary phosphonium salts such as tetraphenylphosphonium bromide, tributylhexadecylphosphonium bromide, and tributyldodecylphosphonium bromide.

[0121] The amount of the phase transfer catalyst is preferably 10 mol % to 1000 mol % of the alkali metal salt used, more preferably 55 mol % to 800 mol %, and even more preferably 85 mol % to 750 mol %. The upper and lower limits of the amount of the phase transfer catalyst can be combined in any manner.

[0122] The reaction temperature in the step of reacting the aromatic polysulfone precursor with the end capping agent is preferably 150-100°C or higher and lower than 200°C, more preferably 130°C or higher and 190°C or lower, and even more preferably 150°C or higher and 180°C or lower.

[0123] The reaction time for the above step is preferably 4 to 15 hours.

[0124] The amount of the end-capping agent used in the above step is preferably 0.1 to 50 parts by mass, more preferably 0.6 to 25 parts by mass, per 100 parts by mass of the aromatic polysulfone precursor.

[0125] The amount of the alkali metal salt used in the above step is preferably 0.3 to 30 parts by mass, more preferably 0.4 to 10 parts by mass, per 100 parts by mass of the aromatic polysulfone precursor.

[0126] In this reaction, in addition to the aromatic polysulfone precursor, end-capping agent, alkali metal salt, phase transfer catalyst, etc., a halogenoaromatic sulfone compound or a dihydroxyaromatic compound may be added as an optional component. The halogenoaromatic sulfone compound may be the compound listed in formula (mx-1) above. The dihydroxyaromatic compound may be the compound listed in formula (my-1).

[0127] According to the method for producing aromatic polysulfone having the above-mentioned configuration, aromatic polysulfone into which polar groups have been introduced can be easily produced.

[0128] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. The combination of each configuration shown in the above-described embodiment is merely an example, and various modifications can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0129] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0130] In this example, the following raw materials and reagents were used.

[0131] Polyethersulfone (PES) PES1: Sumikaexcel PES 3600P manufactured by Sumitomo Chemical Co., Ltd. PES2: Sumikaexcel PES 5900P manufactured by Sumitomo Chemical Co., Ltd.

[0132] End-capping agents Capping agent 1: sodium 4-hydroxybenzenesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) Capping agent 2: dipotassium 2-hydroxy-6,8-naphthalenedisulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) Capping agent 3: 4-aminophenol (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0133] By using capping agent 1, one salt-type sulfonic acid group containing a sodium sulfonate group and a potassium sulfonate group is introduced to the main chain terminal of the aromatic polysulfone. That is, by using capping agent 1, ideally, a total of two salt-type sulfonic acid groups containing a sodium sulfonate group and a potassium sulfonate group are introduced, one at each end of the main chain of the aromatic polysulfone.

[0134] Two salt-type sulfonic acid groups containing a potassium sulfonate group are introduced to the main chain terminal (one end) of the aromatic polysulfone by using capping agent 2. In other words, when capping agent 2 is used, ideally, a total of four salt-type sulfonic acid groups containing a sodium sulfonate group and a potassium sulfonate group are introduced to both ends of the main chain of the aromatic polysulfone.

[0135] An amino group is introduced into the main chain terminal (one end) of the aromatic polysulfone by using the capping agent 3. That is, when the capping agent 3 is used, ideally, two amino groups are introduced, one at each end of the main chain of the aromatic polysulfone.

[0136] Phase transfer catalysts Catalyst 1: 18-crown 6-ether (manufactured by Tokyo Chemical Industry Co., Ltd.) Catalyst 2: 4,13-diazo-18-crown 6-ether (manufactured by Tokyo Chemical Industry Co., Ltd.) Catalyst 3: 15-crown 5-ether (manufactured by Tokyo Chemical Industry Co., Ltd.) Catalyst 4: tetrabutylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0137] ・Alkali metal salt K ２ CO ３ : Potassium carbonate

[0138] Solvent: NMP: N-methyl-2-pyrrolidone DMAc: N,N-dimethylacetamide

[0139] Dihalogeno aromatic sulfone compounds DCDPS: 4,4'-dichlorodiphenyl sulfone DFDPS: 4,4'-difluorodiphenyl sulfone

[0140] Example 1 Into a polymerization vessel equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser with a receiver at its tip, PES1 (100 g), capping agent 1 (4.06 g), K ２ CO ３ (1.79 g), DCDPS (1.80 g), catalyst 1 (5.00 g), and NMP (150 g) were added and mixed in. The resulting mixture was heated to 150° C. and reacted for 15 hours.

[0141] The resulting reaction solution was then cooled to room temperature (25°C) to precipitate unreacted potassium carbonate and by-produced potassium chloride. The reaction solution (slurry) from which the salts had precipitated was added dropwise to water to precipitate aromatic polysulfone, and unnecessary NMP was removed by filtration to obtain a precipitate.

[0142] The resulting precipitate was thoroughly washed repeatedly with methanol and water and dried by heating at 150° C. to obtain aromatic polysulfone 1 having polar groups derived from capping agent 1 at the main chain terminals.

[0143] Example 2 Aromatic polysulfone 2 was obtained in the same manner as in Example 1, except that 3.00 g of catalyst 1 was used.

[0144] Example 3 Aromatic polysulfone 3 was obtained in the same manner as in Example 1, except that 2.00 g of catalyst 1 was used.

[0145] Example 4 Aromatic polysulfone 4 was obtained in the same manner as in Example 1, except that 23.0 g of catalyst 1 was used.

[0146] Example 5 Aromatic polysulfone 5 was obtained in the same manner as in Example 1, except that PES2 was used instead of PES1 and 2.48 g of DCDPS was used.

[0147] Example 6 Aromatic polysulfone 6 was obtained in the same manner as in Example 2, except that PES2 was used instead of PES1 and 2.48 g of DCDPS was used.

[0148] Example 7 Aromatic polysulfone 7 was obtained in the same manner as in Example 4, except that PES2 was used instead of PES1 and 2.48 g of DCDPS was used.

[0149] Example 8 Aromatic polysulfone 8 was obtained in the same manner as in Example 1, except that DMAc was used instead of NMP.

[0150] Example 9 Aromatic polysulfone 9 was obtained in the same manner as in Example 1, except that 1.59 g of DFDPS was used instead of DCDPS.

[0151] Example 10 Aromatic polysulfone 10 was obtained in the same manner as in Example 9, except that PES2 was used instead of PES1 and 2.19 g of DFDPS was used.

[0152] Example 11 Aromatic polysulfone 11 was obtained in the same manner as in Example 10, except that 3.00 g of catalyst 1 was used.

[0153] Example 12 Aromatic polysulfone 12 was obtained in the same manner as in Example 10, except that 23.0 g of catalyst 1 was used.

[0154] Example 13 Aromatic polysulfone 13 was obtained in the same manner as in Example 1, except that 8.90 g of catalyst 2 was used instead of catalyst 1.

[0155] Example 14 Aromatic polysulfone 14 was obtained in the same manner as in Example 1, except that 15.0 g of catalyst 3 was used instead of catalyst 1.

[0156] Example 15 Aromatic polysulfone 15 was obtained in the same manner as in Example 1, except that 5.25 g of catalyst 4 was used instead of catalyst 1.

[0157] Example 16 Aromatic polysulfone 16 was obtained in the same manner as in Example 15, except that 1.59 g of DFDPS was used instead of DCDPS.

[0158] Example 17 Aromatic polysulfone 17 was obtained in the same manner as in Example 1, except that 7.90 g of capping agent 2 was used instead of capping agent 1, the reaction temperature was changed to 180° C., and the reaction time was changed to 10 hours.

[0159] Example 18 Aromatic polysulfone 18 was obtained in the same manner as in Example 1, except that 2.26 g of capping agent 3 was used instead of capping agent 1 and the reaction time was changed to 8 hours.

[0160] Comparative Example 1 An aromatic polysulfone C1 was obtained in the same manner as in Example 1, except that no phase transfer catalyst was added.

[0161] Comparative Example 2 An aromatic polysulfone C2 was obtained in the same manner as in Example 5, except that no phase transfer catalyst was added.

[0162] Comparative Example 3 Aromatic polysulfone C3 was obtained in the same manner as in Example 17, except that no phase transfer catalyst was added and the reaction temperature was changed to 200°C.

[0163] [Calculation of FG amount per 100 repeating units of aromatic polysulfone] The aromatic polysulfones obtained in the examples and comparative examples were dissolved in deuterated dimethyl sulfoxide to prepare samples so that the concentration of the aromatic polysulfone to be measured was 80 mg / ml. The samples were then analyzed under the following measurement conditions: １H-NMR was measured. (Measurement conditions) Measurement device: ECZ400S (manufactured by JEOL) Static magnetic field strength: 9.4 Tesla (resonance frequency: 400 MHz ( １ H) Spinning: 15 Hz Repetition time: 7.2 seconds Number of accumulations: 64 Temperature: 25°C Chemical shift standard: dimethyl sulfoxide

[0164] The following two peak areas were determined from the obtained NMR spectrum. Xp: Peak area assigned to the "hydrogen atom at the α-position of the sulfonyl group" in the above general formula (S-1). Integrated value from 7.17 to 7.34 ppm. Yp: Peak area assigned to the "hydrogen atom at the α-position of the sulfonate group or amino group" in the aromatic ring at the main chain terminal of the aromatic polysulfone. When capping agent 1 was used as the end capping agent, the integrated value was from 7.00 to 7.07 ppm. When capping agent 2 was used as the end capping agent, the integrated value was from 8.48 to 8.53 ppm. When capping agent 3 was used as the end capping agent, the integrated value was from 6.72 to 6.84 ppm.

[0165] The FG amount was calculated using the obtained peak area based on the following formulas (a1) and (a2): When capping agent 1 or capping agent 3 was used as the end-capping agent: FG amount = [(Yp / 2) / (Xp / 4)] x 100 = Yp / Xp x 200 (a1) When capping agent 2 was used as the end-capping agent: FG amount = [Yp / (Xp / 4)] x 100 = Yp / Xp x 400 (a2)

[0166] The results are shown in Table 1 below. In Table 1, the "amount added" of the phase transfer catalyst indicates the ratio (mol %) to the potassium carbonate used.

[0167]

[0168] In Examples 1 to 18, the amount of FG was larger than in Comparative Examples 1 to 3, and it was confirmed that a large amount of FG was introduced into the main chain terminals.

[0169] From the above results, it was confirmed that the present invention is useful.

Claims

1. A method for producing an aromatic polysulfone, comprising the step of reacting an aromatic polysulfone precursor with at least one compound represented by the following formula (A), the aromatic polysulfone precursor having a repeating unit containing a structure represented by the following general formula (S-1) in its main chain and having a halogen atom at the end of the main chain, the step being carried out in an aprotic organic solvent in the presence of at least one alkali metal salt and at least one phase transfer catalyst. １ -SO ２ -ph ２ -O- ... (S-1) [In formula (S-1), ph １ and ph ２ each independently represents a phenylene group which may have a substituent. ｘ -Ar-OM (A) [In formula (A), Ar is an aromatic hydrocarbon group which may have a substituent. Ra is one or more polar groups selected from an acidic group having a pKa equal to or lower than the pKa of a carboxy group, a salt of the acidic group, and a functional group containing a nitrogen atom. x is an integer of 1 or more. M is a hydrogen atom or a monovalent cation] 2. The method for producing aromatic polysulfone according to claim 1, wherein the amount of the phase transfer catalyst is 10 mol % or more and 1000 mol % or less based on the alkali metal salt.

3. The method for producing aromatic polysulfone according to claim 1 or 2, wherein the reaction temperature in the above step is 130°C or higher and lower than 200°C.

4. The method for producing aromatic polysulfone according to claim 1 or 2, wherein the phase transfer catalyst is 18-crown-6-ether.

5. The method for producing aromatic polysulfone according to claim 1 or 2, wherein the alkali metal salt is a potassium salt.

6. The method for producing an aromatic polysulfone according to claim 1 or 2, wherein Ra is a sulfonic acid group, a salt of a sulfonic acid group, or an amino group.

7. The method for producing an aromatic polysulfone according to claim 1 or 2, wherein Ra is a sulfonic acid group or a salt of a sulfonic acid group.

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