JPH08188569A - Production of sulfonium compound - Google Patents

Abstract

PURPOSE: To continuously obtain the subject compound useful as a polymerization curing agent without isolating a sulfonium halide compound which is an intermediate by reacting a sulfonium compound in water without using an organic solvent. CONSTITUTION: (A) A sulfide compound is reacted with (B) a halide compound of the formula R4 X (R4 is a 1-4C alkyl, benzyl, naphthylmethyl or cinnamyl, preferably benzyl, a halogenobenzyl, etc.; X is a halogen) in water and the resultant compound is then reacted with (C) a salt of the formula MY (M is an alkali metal; Y is SbF6 , PF6 , AsF6 or BF4 ) in the presence of an ester-based organic solvent to provide a sulfonium compound. Furthermore, a compound of formula I (R<1> is H, methyl, acetyl, benzoyl, etc.; R2 is H, a halogen or a 1-4C alkyl; R3 is a 1-4C alkyl or benzyl) can preferably be used as the component (A) to afford the sulfonium compound of formula II.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a sulfonium compound. More specifically, the present invention relates to a method for producing a sulfonium compound which is useful as a polymerization catalyst for a photo and / or thermosetting composition and is particularly effective as a polymerization curing agent for a cationically polymerizable vinyl compound such as epoxy resin or styrene.

[0002]

2. Description of the Related Art Conventionally, many methods have been proposed as a method for producing a sulfonium compound. The most versatile method is the reaction of highly reactive alkyl halides with sulfide compounds. In this reaction, an organic solvent is required to dissolve the raw materials, and an organic solvent is usually used as the reaction solvent. When an organic solvent is used, it is industrially unfavorable in consideration of handling and environmental pollution.

Further, in order to obtain sulfonium hexafluoroantimonates useful as a cationic polymerization catalyst, it is necessary to cause NaSbF ₆ or the like to act on the sulfonium halide for salt exchange, but in order to carry out the anion exchange reaction, It is necessary to create a state in which the ions are dissociated, and a step of taking out a sulfonium halide compound which is a reaction intermediate is required. A method of reacting without a solvent is also conceivable, but this method is not industrially preferable because the reaction product is solidified in the reaction vessel.

Further, JP-A-49-55657 discloses an aqueous method as a method for producing a specific bissulfonium salt. However, this method is effective only for specific sulfonium compounds, and further,
It is characterized by the reaction in a strongly acidic aqueous solution, and there is a problem in handling and it is necessary to adjust the acidity of the aqueous solution in advance.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, in producing a sulfonium compound useful as a polymerization catalyst, a sulfide compound and a halide compound represented by R ₁ X are reacted in water, and a sulfonium halide, which is an intermediate product thereof, is simply reacted. Without separating, continuously add the ester organic solvent,
It is produced by the action of a salt represented by MY and an anion exchange reaction. More specifically, the reaction to obtain a sulfonium halide by reacting a sulfide compound with an alkyl halide having 1 to 4 carbon atoms, a substituted or unsubstituted benzyl halide, naphthylmethyl halide, or cinnamyl halide is a water solvent. It was found that this is possible only by subsequently adding an ester organic solvent such as ethyl acetate or butyl acetate to the reaction solution, and causing the salt represented by MY to act on the anion exchange reaction. By carrying out the above, the polymerization catalyst can be easily produced. (However, R ₁ has 1 carbon atom
~ 4 alkyl group, benzyl group, halogenobenzyl group,
Methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, methoxybenzyl group, chlorobenzyl group, dichlorobenzyl group, trichlorobenzyl group, nitrobenzyl group, dinitrobenzyl group, trinitrobenzyl group,
α-naphthylmethyl group, β-naphthylmethyl group, vinylbenzyl group, cinnamyl group, X is a halogen atom, M is an alkali metal, Y is SbF ₆ , PF ₆ ,
Either AsF ₆ or BF ₄ is shown. )

In carrying out the present invention, the sulfide compound as a starting material is not limited and may be a sulfide having any structure. Specific examples include 4-hydroxyphenylmethyl sulfide, 4-acetoxyphenylmethyl sulfide, 4- (methoxycarbonyloxy) phenylmethyl sulfide, tetrahydrothiophene, thiophene, dimethyl sulfide, benzylmethyl sulfide, dibenzyl sulfide, (α-naphthyl Methyl) methyl sulfide, di (α-naphthylmethyl) sulfide and the like.

The above R which is reacted with this sulfide compound
_{As the} halide compound represented by ₁ X, methyl chloride,
Benzyl chloride, chlorobenzyl chloride, methylbenzyl chloride, methoxybenzyl chloride,
Examples include nitrobenzyl chloride, α-naphthylmethyl chloride, β-naphthylmethyl chloride, cinnamyl chloride, benzyl bromide, methylbenzyl bromide, nitrobenzyl bromide, α-naphthylmethyl bromide, and cinnamyl bromide.

These are 1.0 with respect to the sulfide compound.
~ 3.0 molar ratio used. Preferably 1.0 to 1.2
It is a molar ratio. The amount of water used as a medium may be at least a stirrable amount. Further, the reaction catalyst, sulfuric acid, hydrochloric acid, etc. may be added or coexistent. The reaction temperature is 60 ° C. or lower, preferably 25 to 45 ° C.
The reaction time is 0.5 to 120 hours, preferably 10 to 24
Time. This gives a sulfonium halide compound in high yield.

The sulfonium halide obtained by the above reaction is subsequently subjected to ion exchange. An ester organic solvent is essential for this reaction. The ester organic solvent may be one that separates from water and dissolves the produced sulfonium compound, and representative one is ethyl acetate. Examples of the alkali metal salt having a non-nucleophilic anion used in the anion exchange reaction include KSbF ₆ , NaSbF ₆ , KPF ₆ , NaPF ₆ and K.
AsF ₆ , NaAsF ₆ , NaBF ₄ , LiBF _{4 and the} like. It is preferable to add the alkali metal salt in the presence of an ester organic solvent. The reaction temperature is 40 ° C or lower, preferably 20 ° C or lower. The reaction time is 3 hours or less, preferably 1 hour or less. The sulfonium compound extracted into the ester organic solvent is isolated by a known method,
It can be purified.

The sulfonium compounds produced by the present invention include 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate, 4-hydroxyphenylbenzylmethylsulfonium hexafluorophosphate, 4-hydroxyphenylbenzylmethylsulfonium hexafluoroarsenate, and 4-hydroxyphenylbenzylmethylsulfonium hexafluoroarsenate. -Hydroxyphenylbenzylmethylsulfonium tetrafluoroborate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluorophosphate, 4- (methoxycarbonyloxy) phenylbenzylmethylsulfonium hexafluoroantimonate, 4 -Hydroxyphenyl (O-methylbenzyl) methyl Sulfo hexafluoroantimonate, 4-hydroxyphenyl (O-methylbenzyl) methyl sulfonium hexafluorophosphate,
4-hydroxyphenyl (O-methylbenzyl) methylsulfonium hexafluoroarsenate, 4-hydroxyphenyl (O-methylbenzyl) methylsulfonium tetrafluoroborate, 4- (benzoyloxy)
Phenyl (O-methylbenzyl) methylsulfonium hexafluorophosphate, 4-hydroxyphenyl (p-nitrobenzyl) methylsulfonium hexafluoroantimonate, 4-hydroxyphenyl (p-nitrobenzyl) methylsulfonium hexafluorophosphate, 4-acetoxyphenyl (P-Nitrobenzyl) methylsulfonium tetrafluoroborate, 4-
Hydroxyphenyl (α-naphthylmethyl) methylsulfonium hexafluoroantimonate, 4-hydroxyphenyl (α-naphthylmethyl) methylsulfonium hexafluorophosphate, 4-hydroxyphenylcinnamyl methylsulfonium hexafluoroantimonate, 4-hydroxyphenylcinnamyl Methylsulfonium hexafluorophosphate, 4- (methoxycarbonyloxy) phenylcinnamylmethylhexafluoroantimonate, benzyltetramethylenesulfonium hexafluoroantimonate, benzyltetramethylenesulfonium hexafluorophosphate, O
-Methylbenzyltetramethylenesulfonium hexafluoroantimonate, p-nitrobenzyltetramethylenesulfonium hexafluoroantimonate, (α
-Naphthylmethyl) tetramethylenesulfonium hexafluoroantimonate, cinnamyltetramethylenesulfonium hexafluoroantimonate, benzyldimethylsulfonium hexafluoroantimonate,
(Α-naphthylmethyl) dimethylsulfonium hexafluoroantimonate, (α-naphthylmethyl) dimethylsulfonium hexafluoroantimonate, cinnamyldimethylsulfonium hexafluoroantimonate, (α-naphthylmethyl) benzylmethylsulfonium hexafluoroantimonate, Tribenzyl sulfonium hexafluoroantimonate etc. are mentioned.

[0011]

EXAMPLES Examples of the present invention will be shown below, but the scope of the present invention is not limited thereto.

Comparative Example 1 A stirrer, a thermometer and a condenser are installed in a 500 ml four-necked Kolben. The same device is used in the following comparative examples and examples. 4-hydroxyphenylmethyl sulfide 14.5 g, benzyl chloride 1
Charge 4.4 g. When the reaction was started at 40 ° C. in the absence of a solvent, it solidified after 1 hour and could not be stirred.

Comparative Example 2 14.5 g of 4-hydroxyphenylmethyl sulfide,
Charge 14.4 g of benzyl chloride. Methanol 1
Add 00 ml and react at 40 ° C. for 20 hours. After the reaction, methanol was recovered by an evaporator and white crystals 1
8.9 g was obtained. Add water to a 300 ml Erlenmeyer flask.
ml and 100 ml of ethyl acetate are added, and 18.9 g of the above white crystals are charged. Furthermore, NaSbF ₆ was added to 18.3.
g Preparation React at 15 ° C for 1 hour. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 21.8 g. The results of NMR analysis, IR analysis, and elemental analysis,
It was confirmed that the product was 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate. The yield is 66.0%, and the melting point is 109.5-1.
It was 13.0 ° C. The content concentration of chlorine ions determined by ion chromatography was 218 ppm.

Comparative Example 3 4-hydroxyphenylmethyl sulfide 14.5 g,
Charge 14.4 g of benzyl chloride. Add 300 ml of water and react at 40 ° C. for 20 hours. After the reaction, charge 100 ml of toluene and 23.0 g of NaSbF ₆ at 15 ° C.
React for 1 hour. After the reaction, the toluene layer was separated by liquid separation and concentrated under reduced pressure, but only a very small amount of oily matter was obtained, and no crystalline substance was obtained.

Example 1 14.5 g of 4-hydroxyphenylmethyl sulfide,
Charge 14.4 g of benzyl chloride. Add 300 ml of water and react at 40 ° C. for 20 hours. After the reaction, 100 ml of ethyl acetate and 23.0 g of NaSbF _{6 were} charged, and 15
React at 1 ° C for 1 hour. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 37.3 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate. Yield 8
The melting point was 9.8% and the melting point was 113.5 to 115.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 2 14.5 g of 4-hydroxyphenylmethyl sulfide,
Charge 14.4 g of benzyl chloride. Add 300 ml of water and react at 40 ° C. for 20 hours. After the reaction, 100 ml of ethyl acetate and 16.4 g of KPF _{6 are} charged and reacted at 15 ° C. for 30 minutes. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 30.7 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was 4-hydroxyphenylbenzylmethylsulfonium hexafluorophosphate. Yield is 9
The melting point was 1.6% and the melting point was 140.0 to 143.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 3 28.0 g of 4-hydroxyphenylmethyl sulfide,
Charge 30.9 g of O-methylbenzyl chloride. Water 3
Add 00 ml and react at 35 ° C. for 20 hours. After the reaction, 100 ml of ethyl acetate and 47.2 g of KSbF ₆ are charged and reacted at 15 ° C. for 30 minutes. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 78.6g. As a result of NMR analysis, IR analysis, and elemental analysis, the product was 4-hydroxyphenyl (O-methylbenzyl).
It was confirmed to be methylsulfonium hexafluoroantimonate. Yield 95.0%, melting point 1
It was 38.0-139.5 degreeC. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 4 11.8 g of 4-hydroxyphenylmethyl sulfide,
Charge 19.9 g of p-nitrobenzyl bromide. Water 2
Add 00 ml and react at 35 ° C. for 20 hours. After the reaction, 200 ml of ethyl acetate and 20.2 g of NaSbF _{6 were} charged, and the reaction was carried out at 15 ° C. for 30 minutes. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 37.5 g. As a result of NMR analysis, IR analysis, and elemental analysis, the product was 4-hydroxyphenyl (p-nitrobenzyl).
It was confirmed to be methylsulfonium hexafluoroantimonate. The yield is 93.7% and the melting point is 1.
It was 61.0 to 162.5 ° C.

Example 5 13.0 g of 4-hydroxyphenylmethyl sulfide,
Charge 18.1 g of α-naphthylmethyl chloride. Water 3
Add 00 ml and react at 35 ° C. for 20 hours. After the reaction, 150 ml of ethyl acetate and 20.7 g of NaSbF _{6 are} charged, and the mixture is reacted at 15 ° C. for 30 minutes. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 40.0 g. As a result of NMR analysis, IR analysis, and elemental analysis, the product was 4-hydroxyphenyl (α-naphthylmethyl).
It was confirmed to be methylsulfonium hexafluoroantimonate. The yield is 96.6%, and the melting point is 1.
It was 23.0-125.0 degreeC. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 6 7.0 g of 4-hydroxyphenylmethyl sulfide and 8.4 g of cinnamil chloride are charged. Add 300 ml of water and react at 35 ° C. for 20 hours. After the reaction, charge 100 ml of ethyl acetate and 11.6 g of NaSbF ₆ at 15 ° C.
React for 1 hour. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 20.4 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was 4-hydroxyphenylcinnamylmethylsulfonium hexafluoroantimonate. The yield was 92.1%, and the melting point was 124.0 to 126.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 7 4- (Methoxycarbonyloxy) phenylmethyl sulfide 19.8 g, α-naphthylmethyl chloride 1
Charge 9.4g. Add 300 ml of water and run at 35 ° C for 20
React for hours. After the reaction, 100 ml of ethyl acetate, KS
Charge 23.6 g of bF _{6 and} react at 15 ° C. for 30 minutes.
After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 45.0 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was 4- (methoxycarbonyloxy) phenyl (α-naphthylmethyl) methylsulfonium hexafluoroantimonate. The yield is 90.9%, and the melting point is 125.0-12.
It was 7.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 8 Tetrahydrothiophene (7.0 g) and benzyl chloride (11.1 g) were charged. Add 250 ml of water, 4 at 40 ℃
Incubate for 8 hours. After the reaction, 100 ml of ethyl acetate, N
Charge 19.0 g of aSbF _{6 and} react at 15 ° C. for 1 hour. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried.
The yield was 26.2 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was benzyltetramethylenesulfonium hexafluoroantimonate. The yield is 86.0%, and the melting point is 125.
It was 0-127.0 degreeC. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 9 Tetrahydrothiophene (7.0 g) and benzyl chloride (11.1 g) were charged. Add 250 ml of water, 4 at 40 ℃
Incubate for 8 hours. After the reaction, 100 ml of ethyl acetate, K
Charge 12.6 g of PF _{6 and} react at 15 ° C. for 30 minutes.
After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 19.7 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was benzyltetramethylenesulfonium hexafluorophosphate. The yield is 88.7%, and the melting point is 141.0 to 1.
It was 43.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 10 Tetrahydrothiophene (7.0 g) and α-naphthylmethyl chloride (15.4 g) were charged. Add 300 ml of water,
The reaction is carried out at 40 ° C. for 48 hours. After the reaction, ethyl acetate 10
0 ml, 17.7 g of NaSbF ₆ was charged, 30 at 15 ° C
React for minutes. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 28.0 g. NMR analysis, I
As a result of R analysis and elemental analysis, it was confirmed that the product was α-naphthylmethyltetramethylenesulfonium hexafluoroantimonate. Yield 88.2%,
The melting point was 130.0 to 132.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 11 Tetrahydrothiophene (7.0 g) and cinnamil chloride (13.3 g) were charged. Add 250 ml of water and react at 40 ° C. for 48 hours. After the reaction, 100 ml of ethyl acetate,
Charge 17.7 g of NaSbF _{6 and} react at 15 ° C. for 30 minutes. After the reaction, the ethyl acetate layer was separated by liquid separation and concentrated under reduced pressure to give white crystals. The crystals obtained were dried. The yield was 27.1 g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was cinnamyltetramethylenesulfonium hexafluoroantimonate. The yield was 90.1%, and the melting point was 89.0 to 90.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

Example 12 5.0 g of dimethyl sulfide and 15.6 g of α-naphthylmethyl chloride are charged. Add 200 ml of water, 35
React at 48 ° C. for 48 hours. After the reaction, ethyl acetate 100m
1, 17.9 g of NaSbF _{6 was} charged and reacted at 15 ° C. for 30 minutes. After the reaction, the ethyl acetate layer was taken out by liquid separation,
Concentration under reduced pressure gave white crystals. The crystals obtained were dried. The yield was 26.6g. As a result of NMR analysis, IR analysis, and elemental analysis, it was confirmed that the product was dimethyl α-naphthylmethylsulfonium hexafluoroantimonate. The yield was 87.5%, and the melting point was 133.0 to 135.0 ° C. The chlorine ion content concentration determined by ion chromatography analysis was 10 ppm or less.

[0027]

According to the production method of the present invention, a sulfonium compound is reacted in water without using an organic solvent as a reaction medium, and a sulfonium halide compound as an intermediate is continuously isolated from the medium without isolation. Anion exchange reaction can be carried out. Further, it is understood that after the anion exchange reaction, the concentration of halogen ions contained as impurities is low, and the ion exchange reaction proceeds quantitatively. Therefore, the method of the present invention can contribute to an efficient synthetic reaction of a sulfonium compound.

Claims (10)

[Claims] 1. A sulfonium compound characterized by reacting a sulfide compound and a halide compound represented by R ₄ X in water, and subsequently reacting the salt represented by MY in the presence of an ester organic solvent after the reaction. Manufacturing method. (However, R ₄ is an alkyl group having 1 to 4 carbon atoms, a substituted or unsubstituted benzyl group, a naphthylmethyl group, or a cinnamyl group, X is a halogen atom, M is an alkali metal, and Y is SbF. ₆ , PF ₆ , AsF ₆ , or BF ₄ is shown.) 2. R _{4 according} to claim 1, wherein benzyl group, halogenobenzyl group, methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, methoxybenzyl group, chlorobenzyl group, dichlorobenzyl group, trichlorobenzyl group, nitro A method for producing a sulfonium compound represented by any of a benzyl group, a dinitrobenzyl group, a trinitrobenzyl group, an α-naphthylmethyl group, a β-naphthylmethyl group and a vinylbenzyl group. 3. A sulfide compound represented by Chemical formula 1 and R ₄
A method for producing a sulfonium compound represented by Chemical formula 2, which comprises reacting the halide compound represented by X in water, and subsequently reacting the salt represented by MY in the presence of an ester organic solvent after the reaction. Embedded image Embedded image (In the formula, R ₄ is an alkyl group having 1 to 4 carbon atoms, benzyl group, halogenobenzyl group, methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, methoxybenzyl group, chlorobenzyl group, dichlorobenzyl group, trichloro group. Benzyl group, nitrobenzyl group, dinitrobenzyl group, trinitrobenzyl group, α-naphthylmethyl group, β-naphthylmethyl group, vinylbenzyl group, cinnamyl group, R ₁ is hydrogen, methyl group, acetyl group , Methoxycarbonyl group, ethoxycarbonyl group,
A benzoyl group, a phenoxycarbonyl group, a chloroacetyl group, a dichloroacetyl group, a trichloroacetyl group, or a trifluoroacetyl group, and R ₂ is hydrogen, a halogen, or an alkyl group having 1 to 4 carbon atoms, ₃
Is an alkyl group having 1 to 4 carbon atoms or a benzyl group, X
Is a halogen atom, M is an alkali metal, Y is SbF
₆ , ₆ , PF ₆ , AsF ₆ , or BF ₄ . ) 4. A sulfide compound represented by R ₅ —S—R ₆ is reacted with a halide compound represented by R ₄ X in water, and after the reaction, MY is added in the presence of an ester organic solvent.
R ₄ R ₅ R ₆ characterized by acting a salt represented by
A method for producing a sulfonium compound represented by S ⁺ Y ⁻ . (In the formula, R ₄ is an alkyl group having 1 to 4 carbon atoms, benzyl group, halogenobenzyl group, methylbenzyl group, dimethylbenzyl group, trimethylbenzyl group, methoxybenzyl group, chlorobenzyl group, dichlorobenzyl group, trichloro group. Benzyl group, nitrobenzyl group, dinitrobenzyl group, trinitrobenzyl group, α-naphthylmethyl group, β
A naphthylmethyl group, a vinylbenzyl group, or a cinnamyl group, and R ₅ and R ₆ are each an alkyl group having 1 to 4 carbon atoms, a benzyl group, a halogenobenzyl group, or
R ₅ and R ₆ may form a sulfur-containing heterocycle together with the adjacent sulfur atom. X represents a halogen atom, M represents an alkali metal, and Y represents SbF ₆ , PF ₆ , AsF ₆ , or BF ₄ . ) 5. The method for producing a sulfonium compound according to claim 4, wherein R ₆ is a methyl group. 6. A method for producing a sulfonium compound, wherein the sulfide compound represented by R ₅ —S—R _{6 according} to claim 4 is tetrahydrothiophene. 7. A method for producing a sulfonium compound, wherein the reaction temperature is 45 ° C. or lower in the reaction in water according to claim 1. 8. A method for producing a sulfonium compound, wherein the charged molar ratio of the halide compound represented by R ₄ X according to any one of claims 1 to 6 is 1.0 or more and 1.2 or less with respect to the sulfide compound. 9. A method for producing a sulfonium compound, wherein the ester organic solvent according to claim 1 is ethyl acetate. 10. A process for producing a sulfonium compound, wherein the reaction temperature is 20 ° C. or lower in the action of the salt represented by MY according to claim 1.