JP2020002115A - Method for producing sulfonium salt - Google Patents

Abstract

［Ａｒ１、Ａｒ２及びＡｒ３は各々、置換／非置換のアリール基；Ｘは有機酸又は無機酸のアニオン残基］
【選択図】なしProvided is a simple method for producing a sulfonium salt useful as a quencher, particularly a triarylsulfonium having an arylthio group and having an anion residue such as a sulfonic acid or a carboxylic acid, without limitation to the structure of the sulfonium.
A method for producing a sulfonium salt of the formula (2), wherein the sulfonium salt of the formula (1) is reacted with a Lewis acid and then reacted with an alkali metal salt of an organic acid or an inorganic acid.

[Ar1, Ar2 and Ar3 are each a substituted / unsubstituted aryl group; X is an anionic residue of an organic acid or an inorganic acid]
[Selection diagram] None

Description

  The present invention relates to a method for producing a sulfonium salt. More specifically, the present invention relates to a method for producing a sulfonium salt suitable as a quencher for a chemically amplified resist used for forming a semiconductor pattern.

  Conventionally, as a cationic photopolymerization initiator for generating an acid upon irradiation with active energy rays such as light or an electron beam or a photoacid generator for a resist, a salt having an onium such as iodonium or sulfonium or a transition metal complex as a cation component is known. Have been. Among the cation components of these salts, those containing sulfonium, particularly sulfonium having an aryl group, have been awarded from the viewpoint of high acid generation efficiency by active energy ray irradiation and good storage stability in the resist composition. I have.

  On the other hand, a resist material used in a lithography process in the field of microfabrication represented by semiconductor production includes the photoacid generator and, for example, a tert-butyl ester group of carboxylic acid or a tert-butyl carbonate group of phenol. A quencher may be included in addition to the polymer having the quencher. This quencher has the role of improving the contrast between exposed and unexposed areas by trapping the acid generated by exposure and controlling diffusion, and is similar to a basic nitrogen-containing organic compound or a sulfonium salt or an iodonium salt. Photodegradable bases and the like. Since the photodegradable base has a weak acid anion residue such as sulfonic acid or carboxylic acid, the non-exposed part of light or radiation suppresses the diffusion of strong acid by salt exchange with the generated strong acid, while exposing to light or radiation. In the part, the compound is decomposed, so that the quenching ability is reduced, and the compound has a function of hardly causing a decrease in sensitivity, and exhibits an effect of improving characteristics such as roughness of a resist pattern.

  As a method for synthesizing a sulfonium salt having a weak acid anion residue such as a sulfonic acid or a carboxylic acid, an organometallic compound and a sulfoxide are reacted as a Lewis acid in the presence of an organosilicon compound, and then reacted with a carboxylic acid or a salt thereof. (Patent Document 1), a method of reacting an aryl halide with a sulfoxide in the presence of a Lewis acid, followed by a reaction with a carboxylic acid or a salt thereof (Patent Document 2), a method of reacting a diaryl sulfide having a carboxylic acid ester site with an iodonium salt. To obtain a sulfonium salt, and then decompose the ester with a base (Patent Document 3).

JP-A-2004-315430 JP 2009-84219 A JP 2017-202993 A

  However, the methods disclosed in Patent Documents 1, 2 and 3 all involve a sulfonium-forming reaction, and thus the structure of the resulting sulfonium salt is limited. Specifically, there are only triphenylsulfonium having a halogen atom, an alkyl group, or the like as a substituent, and sulfonium which forms a salt in the molecule.

Accordingly, the present invention provides a simple method for producing a sulfonium salt useful as a quencher, which is not limited to the structure of sulfonium, and is particularly a triarylsulfonium having an arylthio group and having a weak acid anion residue such as sulfonic acid or carboxylic acid. The purpose is to do.

The present inventors have studied to achieve the above object, and as a result, have reached the present invention.
That is, the present invention is characterized in that a sulfonium salt (A) represented by the following general formula (1) is reacted with a Lewis acid (B) and then with an alkali metal salt (C) of an organic or inorganic acid. This is a method for producing a sulfonium salt (D) represented by the following general formula (2).

[In the formulas (1) and (2), Ar1, Ar2 and Ar3 each represent an aryl group which may have a substituent, and X represents an anionic residue of an organic acid or an inorganic acid. ]

  According to the present invention, a sulfonium salt having a weak acid anion residue such as a sulfonic acid or a carboxylic acid can be produced.

<Sulfonium salt (A)>
In the present invention, the sulfonium salt (A) is represented by the general formula (1).

In the formula (1), Ar1, Ar2 and Ar3 each represent an aryl group which may have a substituent.

  An aryl group refers to a monocyclic aromatic hydrocarbon or a condensed polycyclic aromatic hydrocarbon having 6 to 30 carbon atoms, and a monocyclic heterocyclic compound or a condensed polycyclic heterocyclic compound having 4 to 30 carbon atoms. It is a group with a skeleton.

  Examples of the monocyclic aromatic hydrocarbon having 6 to 30 carbon atoms or the condensed polycyclic aromatic hydrocarbon of the aryl group include benzene, naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, benzanthracene, anthraquinone, fluorene, Naphthoquinone and the like.

  Examples of the monocyclic heterocyclic compound or fused polycyclic heterocyclic compound having 4 to 30 carbon atoms of the aryl group include thiophene, furan, pyrrole, oxazole, thiazole, pyridine, pyrimidine, pyrazine, indole, benzofuran, benzothiophene, Examples include quinoline, isoquinoline, quinoxaline, quinazoline, carbazole, acridine, phenothiazine, phenazine, xanthene, thianthrene, phenoxazine, phenoxatiin, chroman, isochroman, dibenzothiophene, xanthone, thioxanthone, and dibenzofuran.

  Examples of the substituent of the aryl group include an alkyl group, a hydroxy group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, and an aryl group. Group, a heterocyclic hydrocarbon group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, an alkyleneoxy group, an amino group, a cyano group, a nitro group and a halogen atom. Or two or more kinds.

  Examples of the alkyl group include those having 1 to 18 carbon atoms such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl and n-octadecyl. Linear alkyl group, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, branched alkyl group having 1 to 18 carbon atoms such as isohexyl and isooctadecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and A cycloalkyl group having 3 to 18 carbon atoms such as 4-decylcyclohexyl, or a linear or branched fluoroalkyl group having 1 to 4 carbon atoms such as trifluoromethyl, pentafluoroethyl, heptafluoropropyl, and nonafluorobutyl is exemplified.

  Examples of the alkoxy group include a linear or branched C1-C18 alkoxy group such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, hexyloxy, decyloxy, dodecyloxy and octadecyloxy. Is mentioned.

  Examples of the alkylcarbonyl group include acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, octanoyl, decanoyl, dodecanoyl, dodecanoyl, octadecanoyl, and the like. And a branched alkylcarbonyl group.

  Examples of the arylcarbonyl group include an arylcarbonyl group having 7 to 11 carbon atoms such as benzoyl and naphthoyl.

  Examples of the alkoxycarbonyl group include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, octyloxycarbonyl, tetradecyloxycarbonyl, and octadecyloxycarbonyl. A linear or branched alkoxycarbonyl group having 2 to 19 carbon atoms is exemplified.

  Examples of the aryloxycarbonyl group include an aryloxycarbonyl group having 7 to 11 carbon atoms such as phenoxycarbonyl and naphthoxycarbonyl.

  Examples of the arylthiocarbonyl group include arylthiocarbonyl groups having 7 to 11 carbon atoms, such as phenylthiocarbonyl and naphthoxythiocarbonyl.

  Examples of the acyloxy group include acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isopropylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octylcarbonyloxy, tetradecylcarbonyloxy, and octadecylcarbonyl. Examples thereof include a straight or branched acyloxy group having 2 to 19 carbon atoms such as oxy.

  Examples of the arylthio group include phenylthio, 2-methylphenylthio, 3-methylphenylthio, 4-methylphenylthio, 2-chlorophenylthio, 3-chlorophenylthio, 4-chlorophenylthio, 2-bromophenylthio, and 3-bromophenyl Thio, 4-bromophenylthio, 2-fluorophenylthio, 3-fluorophenylthio, 4-fluorophenylthio, 2-hydroxyphenylthio, 4-hydroxyphenylthio, 2-methoxyphenylthio, 4-methoxyphenylthio, 1-naphthylthio, 2-naphthylthio, 4- [4- (phenylthio) benzoyl] phenylthio, 4- [4- (phenylthio) phenoxy] phenylthio, 4- [4- (phenylthio) phenyl] phenylthio, 4- (phenylthio) phenylthio , 4 Benzoylphenylthio, 4-benzoyl-2-chlorophenylthio, 4-benzoyl-3-chlorophenylthio, 4-benzoyl-3-methylthiophenylthio, 4-benzoyl-2-methylthiophenylthio, 4- (4-methylthiobenzoyl) Phenylthio, 4- (2-methylthiobenzoyl) phenylthio, 4- (p-methylbenzoyl) phenylthio, 4- (p-ethylbenzoyl) phenylthio 4- (p-isopropylbenzoyl) phenylthio and 4- (p-tert-butylbenzoyl) ) Arylthio groups having 6 to 20 carbon atoms, such as phenylthio.

  Examples of the alkylthio group include methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, sec-butylthio, tert-butylthio, pentylthio, isopentylthio, neopentylthio, tert-pentylthio, octylthio, decylthio, dodecylthio, and isooctadecylthio. And linear or branched alkylthio groups having 1 to 18 carbon atoms.

  Examples of the aryloxy group include an aryloxy group having 6 to 10 carbon atoms such as phenoxy and naphthyloxy.

  Examples of the alkylsulfinyl group include methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, butylsulfinyl, isobutylsulfinyl, sec-butylsulfinyl, tert-butylsulfinyl, pentylsulfinyl, isopentylsulfinyl, neopentylsulfinyl, tert-pentylsulfinyl, Examples thereof include a linear or branched alkylsulfinyl group having 1 to 18 carbon atoms such as octylsulfinyl and isooctadecylsulfinyl.

  Examples of the arylsulfinyl group include arylsulfinyl groups having 6 to 10 carbon atoms such as phenylsulfinyl, tolylsulfinyl and naphthylsulfinyl.

  Examples of the alkylsulfonyl group include methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, tert-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, tert-pentylsulfonyl, Examples thereof include linear or branched alkylsulfonyl groups having 1 to 18 carbon atoms such as octylsulfonyl and octadecylsulfonyl.

  Examples of the arylsulfonyl group include arylsulfonyl groups having 6 to 10 carbon atoms such as phenylsulfonyl, tolylsulfonyl (tosyl group) and naphthylsulfonyl.

  The alkyleneoxy group is represented by the following general formula (3).

  In the formula, Q represents a hydrogen atom or a methyl group, and k represents an integer of 1 to 5.

Among these substituents, from the viewpoint of ease of synthesis, an alkyl group, an alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an alkylthio group, an aryl group, A heterocyclic hydrocarbon group, an aryloxy group, an arylsulfinyl group, an arylsulfonyl group, a fluorine atom and a chlorine atom are preferred, and an alkylcarbonyl group, an arylcarbonyl group, an arylthiocarbonyl group, an arylthio group, an aryl group, A cyclic hydrocarbon group, an aryloxy group, an arylsulfinyl group, and an arylsulfonyl group.
Particularly preferably, one of the substituents of Ar1, Ar2 and Ar3 is an arylthio group.

  Specific examples of the cation of the sulfonium salt (A) represented by the general formula (1) are shown below.

<Lewis acid (B)>
Examples of the Lewis acid (B) include zinc chloride, aluminum chloride, aluminum bromide, iron (II) chloride, and iron (III) chloride. From the viewpoints of reactivity and ease of extraction of the product, chloride is used. Aluminum is preferred.

<Alkali metal salt of organic acid or inorganic acid (C)>
Examples of the organic acid of the alkali metal salt (C) of an organic acid or an inorganic acid include alkylsulfonic acids such as methanesulfonic acid, propanesulfonic acid, and butanesulfonic acid, trifluoromethanesulfonic acid, pentafluoroethanesulfonic acid, and nonafluorobutanesulfonic acid. Fluorinated alkylsulfonic acid such as acid, benzenesulfonic acid, p-toluenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, aromatic sulfonic acid such as dodecylbenzenesulfonic acid, formic acid, acetic acid, propionic acid, butyric acid, Valeric acid, isovaleric acid, methylethylacetic acid, trimethylacetic acid, caproic acid, isocaproic acid, diethylacetic acid, 2,2-dimethylbutyric acid, enanthic acid, caprylic acid, pelargonic acid, 2-ethylhexanoic acid, n-undecylenic acid, Lauric acid, n-tridecylenic acid, myristic acid Fluorination of saturated aliphatic carboxylic acids such as n-pentadecylenic acid, palmitic acid, margaric acid, stearic acid, n-nonadecylenic acid, arachidic acid, n-henoic acid, trifluoroacetic acid, pentafluoropropionic acid, heptafluorobutyric acid and the like Saturated aliphatic carboxylic acid, acrylic acid, crotonic acid, isocrotonic acid, vinyl acetic acid, methacrylic acid, 2-pentenoic acid, 3-pentenoic acid, allyl acetic acid, angelic acid, tiglic acid, 3-methyl crotonic acid, 2-hexenoic acid , 3-hexenoic acid, 4-hexenoic acid, 5-hexenoic acid, 2-methyl-2-pentenoic acid, 3-methyl-2-pentenoic acid, 4-methyl-2-pentenoic acid, 4-methyl-2-pentene Acid, 4-methyl-3-pentenoic acid, 2-ethylcrotonic acid, 2-heptenoic acid, 2-octenoic acid, palmitole Acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, unsaturated aliphatic carboxylic acids such as elestearic acid, arachidonic acid, cyclopropanecarboxylic acid, cyclobutanecarboxylic acid, cyclobutenecarboxylic acid, cyclopentanecarboxylic acid, cyclopentene Carboxylic acids, cyclohexanecarboxylic acids, cyclohexenecarboxylic acids, cycloheptanecarboxylic acids, cycloaliphatic carboxylic acids such as cycloheptenecarboxylic acids, benzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 3-ethylbenzoic acid, Examples thereof include aromatic carboxylic acids such as 4-ethylbenzoic acid, salicylic acid, 4-hydroxybenzoic acid, 2-methoxybenzoic acid, 3-methoxybenzoic acid, and 4-methoxybenzoic acid.

  Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, hydrobromic acid, hydroiodic acid, phosphoric acid and the like.

Among the above organic acids and inorganic acids, sulfonic acids and carboxylic acids are preferable from the viewpoint of adaptability as a quencher, that is, acid strength and solubility of a sulfonium salt in a solvent, and alkylsulfonic acid, p-toluenesulfonic acid, -Ethylhexanoic acid, heptafluorobutyric acid and salicylic acid are particularly preferred.

  Examples of the alkali metal include lithium, sodium, and potassium, and sodium or potassium is preferable from the viewpoint of easy availability of a salt with the above acid.

  In the production method of the present invention, the molar ratio of the sulfonium salt (A) to the Lewis acid (B) is usually 1 to 10 mol, preferably 2 to 5 mol, of the Lewis acid (B) per 1 mol of the sulfonium salt (A). It is. When the amount of the Lewis acid (B) is less than 1 mol per mol of the sulfonium salt (A), the yield of the next salt exchange reaction is low. When the amount exceeds 10 mol, the Lewis acid (B) is used more than necessary. As a result, a large amount of acidic wastewater is generated, the operation becomes complicated, and the cost increases.

  In the production method of the present invention, the molar ratio of the sulfonium salt (A) to the alkali metal salt of an organic acid or inorganic acid (C) is usually 1 mole of the sulfonium salt (A) to the alkali metal salt of an organic acid or inorganic acid. (C) The amount is 1 to 5 mol, preferably 1.1 to 2 mol. When the amount of the alkali metal salt (C) of an organic acid or an inorganic acid is less than 1 mol per mol of the sulfonium salt (A), the yield of a target salt exchange reaction is low. Since an alkali metal salt (C) of an acid or an inorganic acid is used, the cost increases.

  In the production method of the present invention, the Lewis acid (B) is an essential component. Usually, in metathesis of a sulfonium salt, an anion exchange reaction proceeds to an anion corresponding to a conjugate base of a stronger acid. That is, since the anion of the sulfonium salt (A) of the present invention is hexafluorophosphate, the anion exchange reaction to the anionic residue of carboxylic acid or sulfonic acid, which is a weaker acid, does not usually proceed. However, by reacting the Lewis acid (B) of the present invention with the sulfonium salt (A) first, hexafluorophosphate which is an anion is decomposed, and a sulfonium salt having a Lewis acid-derived complex ion or halide ion as an anion is intermediate. Since it is formed as a body, an exchange reaction to a target anion becomes possible by a reaction with an alkali metal salt (C) of an organic acid or an inorganic acid in the next step. Therefore, the production method of the present invention cannot be established without the presence of the Lewis acid (B).

  In the production method of the present invention, the molar ratio of the sulfonium salt (A) to the alkali metal salt of an organic acid or inorganic acid (C) is usually 1 mole of the sulfonium salt (A) to the alkali metal salt of an organic acid or inorganic acid. (C) The amount is 1 to 5 mol, preferably 1.1 to 2 mol. When the amount of the alkali metal salt (C) of an organic acid or an inorganic acid is less than 1 mol per mol of the sulfonium salt (A), the yield of a target salt exchange reaction is low. Since an alkali metal salt (C) of an acid or an inorganic acid is used, the cost increases.

  In the production method of the present invention, the reaction between the sulfonium salt (A) and the Lewis acid (B) may be performed in the presence of a solvent, if necessary. The solvent used in that case is not particularly limited as long as it can dissolve the sulfonium salt (A), and examples thereof include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, and tert-butanol; Examples include ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ethers such as diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran and dioxane, chlorinated organic solvents such as dichloromethane and chloroform, and polar organic solvents such as acetonitrile. One of these solvents may be used, or two or more of them may be used in combination. Preferred among these solvents are ethers, ketones, and chlorinated organic solvents, and particularly preferred are diethyl ether, dichloromethane, and chloroform.

  The amount of the solvent used is such that the proportion of the sulfonium salt (A) is usually 1 to 50% by weight, preferably 5 to 20% by weight.

  In the production method of the present invention, the reaction temperature in the reaction of the sulfonium salt (A) with the Lewis acid (B) is from -30 ° C to 10 ° C, preferably from -20 ° C to 0 ° C. In the reaction with the metal salt (C), the temperature is 0 ° C to 60 ° C, preferably 10 ° C to 30 ° C.

  In the production method of the present invention, after the reaction between the sulfonium salt (A) and the Lewis acid (B), the reaction solution is preferably poured into water to decompose excess Lewis acid (B) and terminate the reaction. Since the reaction intermediate is soluble in an organic solvent, the reaction intermediate can be extracted by further adding an organic solvent such as diethyl ether or chloroform.

  When a triarylsulfonium has a halogen atom, an alkyl group, or the like as a substituent (Patent Document 5 or 6), the solubility of the reaction intermediate in water is high, so that extraction with an organic solvent becomes difficult, and the yield is extremely high. To decline. On the other hand, in the case of the sulfonium salt (A) in the production method of the present invention, since the extraction with an organic solvent is possible, a reaction by-product derived from the Lewis acid (B) can be separated, and the salt exchange reaction in the next step is performed. It proceeds easily, and the desired sulfonium salt (D) can be recovered in good yield.

  The obtained sulfonium salt (D) may be, if necessary, alcohols such as methanol, propanol, isopropanol, butanol, isobutanol, tert-butanol, ethers such as diethyl ether, diisopropyl ether, dibutyl ether, ethyl acetate, butyl acetate and the like. Or a mixture of two or more solvents, such as esters, aromatic hydrocarbons such as toluene and xylene, or aliphatic hydrocarbons such as pentane, hexane, cyclohexane and octane. The purity can be improved by recrystallization with one or two or more of the above-mentioned mixed solvents, or by arbitrarily combining the above-mentioned washing and recrystallization operations.

  Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified,% means% by weight and part means parts by weight.

<Production Example 1>
<Method for producing (4-phenylthiophenyl) diphenylsulfonium hexafluorophosphate [intermediate (1)]>
After uniformly mixing 4.3 parts of potassium hexafluorophosphate, 10 parts of acetonitrile, 3.6 parts of diphenyl sulfide, 4.1 parts of diphenyl sulfoxide and 5.9 parts of acetic anhydride, 2.3 parts of concentrated sulfuric acid is added at room temperature. It was dropped. After stirring at 40 ° C. for 1 hour, the mixture was cooled to room temperature, 20 parts of water was added, and the mixture was stirred for 10 minutes. The organic layer was washed with a 20% aqueous sodium hydroxide solution and water three times, and then the solvent was distilled off with an evaporator to obtain (4-phenylthiophenyl) diphenylsulfonium hexafluorophosphate [intermediate (1)]. 9.7 parts were obtained.

<Production Example 2>
<Method for producing [4- (4-biphenylylthio) phenyl] -4-biphenylylphenylsulfonium hexafluorophosphate [intermediate (2)]>
2.0 parts of 4- (phenylthio) biphenyl, 8.0 parts of acetonitrile, 0.37 parts of sulfuric acid and 0.43 parts of 30% hydrogen peroxide were uniformly mixed and reacted at 65 ° C. for 3 hours. After the reaction solution was cooled to room temperature, it was poured into water to precipitate a solid, which was collected by filtration to obtain a mixture containing 55% of 4- (phenylsulfinyl) biphenyl and 45% of 4- (phenylthio) biphenyl as a white solid. Got.
2.0 parts of a mixture containing 55% of the obtained 4- (phenylsulfinyl) biphenyl and 45% of 4- (phenylthio) biphenyl, 0.24 part of 4- (phenylthio) biphenyl, 1.2 parts of acetic anhydride, trifluoromethane 0.72 parts of sulfonic acid and 6.5 parts of acetonitrile were uniformly mixed and reacted at 60 ° C. for 2 hours. After cooling the reaction solution to room temperature, it was poured into 30 parts of water, extracted with 30 parts of dichloromethane, and washed with water until the pH of the aqueous layer became neutral. After washing the dichloromethane layer with 30 parts of toluene and then 30 parts of hexane, 8.4 parts of a 10% aqueous potassium hexafluorophosphate solution was added, stirred for 1 hour, and washed three times with water. The solvent was distilled off using an evaporator to obtain 2.6 parts of [4- (4-biphenylylthio) phenyl] -4-biphenylylphenylsulfonium hexafluorophosphate [intermediate (2)].

<Example 1>
<Method for producing (4-phenylthiophenyl) diphenylsulfonium salicylate (1)>

  5.0 parts of (4-phenylthiophenyl) diphenylsulfonium hexafluorophosphate [intermediate (1)] obtained in Production Example 1 was dissolved in 46 parts of chloroform, cooled to 0 ° C, and then cooled to 5.2 parts of aluminum chloride. And stirred. One hour later, the reaction mixture was poured into 52 parts of water, stirred for 30 minutes, and then left standing to remove an aqueous layer. The organic layer was washed with stirring five times with water, and then 32.5 parts of a 5% aqueous sodium salicylate solution was added, stirred for 1 hour, and allowed to stand, and then the aqueous layer was removed. After the organic layer was washed with water five times with stirring, the solvent was distilled off with an evaporator to obtain a brown viscous substance. Subsequently, the solvent was washed with tert-butyl methyl ether to obtain 4.4 parts of the title compound (1). The product was identified by 1H-NMR.

<Example 2>
<Method for producing (4-phenylthiophenyl) diphenylsulfonium (2) heptafluorobutanoate>

In the same manner as in Example 1, except that 32.5 parts of a 5% aqueous sodium salicylate solution was changed to 48.0 parts of a 5% aqueous sodium heptafluorobutanoate solution, the same operation as in Example 1 was carried out to obtain the title compound (2) 5. 1 part was obtained. The product was identified by 1H-NMR. Further, signals of 3F; t, 2F; m and 2F; t were confirmed by 19F-NMR.

<Example 3>
<Method for producing (4-phenylthiophenyl) diphenylsulfonium hexanesulfonate (3)>

In the same manner as in Example 1, except that 32.5 parts of a 5% aqueous sodium salicylate solution was changed to 38.2 parts of a 5% aqueous sodium hexanesulfonate solution, the same operation as in Example 1 was carried out to obtain the title compound (3). Six parts were obtained. The product was identified by 1H-NMR.

<Example 4>
<Production method of [4- (4-biphenylylthio) phenyl] -4-biphenylylphenylsulfonium (4) salicylate>

  5.0 parts of [4- (4-biphenylylthio) phenyl] -4-biphenylylphenylsulfonium hexafluorophosphate [intermediate (2)] obtained in Production Example 2 was dissolved in 36 parts of chloroform, and 0 ° C. After cooling, 4.0 parts of aluminum chloride was charged and stirred. One hour later, the reaction mixture was added to 40 parts of water, stirred for 30 minutes, and left standing to remove an aqueous layer. The organic layer was stirred and washed five times with water, and then 25.1 parts of a 5% aqueous sodium salicylate solution was added thereto, stirred for 1 hour, and allowed to stand, and then the aqueous layer was removed. After the organic layer was washed with water five times with stirring, the solvent was distilled off with an evaporator to obtain a brown viscous substance. Subsequently, the solvent was washed with tert-butyl methyl ether to obtain 4.4 parts of the title compound (4). The product was identified by 1H-NMR.

<Example 5>
<Method for producing [4- (4-biphenylylthio) phenyl] -4-biphenylylphenylsulfonium (5) heptafluorobutanoate>

In the same manner as in Example 4, except that 25.1 parts of a 5% aqueous sodium salicylate solution was changed to 37.1 parts of a 5% aqueous sodium heptafluorobutanoate solution, the same operation as in Example 4 was carried out to give the title compound (5). Obtained. The product was identified by 1H-NMR. Further, signals of 3F; t, 2F; m and 2F; t were confirmed by 19F-NMR.

<Example 6>
<Method for producing [4- (4-biphenylylthio) phenyl] -4-biphenylylphenylsulfonium (6) hexanesulfonate>

A title compound (6) was obtained in the same manner as in Example 4, except that 25.1 parts of a 5% aqueous sodium salicylate solution was changed to 29.5 parts of a 5% aqueous sodium hexanesulfonate solution. Was. The product was identified by 1H-NMR.

As described above, according to the production method of the present invention, a sulfonium salt having an anionic residue such as sulfonic acid or carboxylic acid can be easily synthesized. This sulfonium salt is useful as a quencher because it generates an acid having a low acid strength such as a sulfonic acid or a carboxylic acid by irradiation with active energy rays such as light or electron beams.

Claims (5)

The following general formula, wherein the sulfonium salt (A) represented by the following general formula (1) is reacted with a Lewis acid (B), and then reacted with an alkali metal salt (C) of an organic acid or an inorganic acid. A method for producing the sulfonium salt (D) represented by (2).

[In the formulas (1) and (2), Ar1, Ar2 and Ar3 each represent an aryl group which may have a substituent, and X represents an anionic residue of an organic acid or an inorganic acid. ]   The production method according to claim 1, wherein one of the substituents on Ar1, Ar2, and Ar3 of the sulfonium salt (A) and the sulfonium salt (D) is an arylthio group. 3. The method according to claim 1, wherein the Lewis acid (B) is aluminum chloride.   The production method according to any one of claims 1 to 3, wherein in the general formula (2), X is an anionic residue of a sulfonic acid or a carboxylic acid. The process according to any one of claims 1 to 4, further comprising a step of, after reacting the sulfonium salt (A) with the Lewis acid (B), extracting a component soluble in an organic solvent from a reaction mixture charged with water. Method.