JP2006131612A - Method for producing sulfonium compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sulfonium compound, more concretely, the method for efficiently and in high purity and good efficiency producing the compound useful as a curing initiator of a photo- and/or heat-curable epoxy resin composition or a polymerization and curing initiator of a cationically polymerizable vinyl compound such as styrene. <P>SOLUTION: The method for producing a 4-acyloxyphenyldialkylsulfonium compound involves reacting a 4-acyloxyphenylalkylsulfide compound with dimethyl sulfate in an acetic ester as a solvent to afford a sulfonium salt, and subjecting the sulfonium salt to salt exchange. In the second embodiment, the method for producing the 4-acyloxyphenyldialkylsulfonium compound involves reacting a 4-hydroxyphenyldialkylsulfonium compound with an acid anhydride represented by R<SB>1</SB>OR<SB>1</SB>(wherein, R<SB>1</SB>is an acyl group or an alkylsulfonyl group) in the presence of dicyclohexylamine in ethyl acetate as a solvent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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 having an effect as a curing initiator of a light and / or thermosetting epoxy resin composition or as a polymerization curing initiator of a cationically polymerizable vinyl compound such as styrene.

Published Patent Publication No. 200071 Published Patent Publication No. 1996/88569 Published Patent Publication No. 290658, Heisei 1 Published Patent Publication No. 172967

According to Patent Document 1, a sulfonium compound that can be produced by the production method of the present invention, and this production method are disclosed. Here, the alkali metal salt or ammonium salt of a predetermined acid starting from 4-substituted oxyphenyl dialkylsulfonium chloride corresponding to the first, or 4-substituted oxyphenyl dialkylsulfonium methyl sulfate, such as NaSbF ₆ ,
A method of synthesis by reacting with any of KSbF ₆ , NaPF ₆ , KPF ₆ , KBF ₄ , NH ₄ SbF _{6 in} a predetermined anhydrous or hydrous ethyl acetate solvent, and secondly, 4-hydroxyphenyl dialkylsulfonium compound and acetyl chloride A method has been proposed in which an acid halide such as methyl chloroformate is reacted in the presence of a tertiary amine to give a 4-substituted oxyphenyl dialkylsulfonium compound.

By the way, the method of patent document 1 was not necessarily a satisfactory manufacturing method. For example, in the first method, methoxycarbonyloxy group, acetoxy group, benzyloxycarbonyloxy group and dimethylamino group are exemplified as 4-substituted oxy groups, but these groups are added to the system as raw materials, for example. It is slightly degraded by acidic inorganic salts such as NaSbF _6.

In addition, it has been found that the second method has a high reactivity of the raw material acid halide and performs a side reaction with a solvent or the like. In addition, although common to the first and second methods, the halogen ions derived from the raw material remain in the product, and further purification is necessary to use it as a polymerization curing initiator for electronic materials that repels halogen ions. Not industrially satisfactory.

According to Patent Document 2, a manufacturing method similar to the manufacturing method of the present invention is disclosed. Here, 4-acyloxyphenyl dialkylsulfonium halide is derived from a 4-acyloxyphenyl alkylsulfide compound and an alkyl halide in water, and ethyl acetate is added. In this two-phase system of water-ethyl acetate, for example, NaSbF ₆ ,
KSbF ₆ , NaPF ₆ , KPF ₆ , KBF ₄ , NH ₄ SbF ₆ is allowed to act to obtain 4-acyloxyphenyl dialkylsulfonium polyfluoro submetallic salt. The feature of this Patent Document 2 is that the reaction is carried out in a water-ethyl acetate two-phase system, so that the necessary 4-acyloxyphenyl dialkylsulfonium polyfluorometallate is transferred to the ethyl acetate layer and the inorganic salt is transferred to the water layer. . Therefore, the target product can be obtained only by treating the ethyl acetate layer.

Patent Document 3 is a method for producing a sulfonium compound, and discloses a production method similar to the previous step of the production method of the present invention. Here, thioanisole derivative and dimethyl sulfate are allowed to act to lead to 4-acyloxyphenyl dialkylsulfonium methyl sulfate, and toluene is shown as the solvent. However, Patent Document 3 does not disclose the superiority of acetate solvents.

Patent Document 4 is also a method for producing a sulfonium compound, and a production method similar to the production method of the present invention is disclosed. Here, there is a description of a dicarbonate diester as an acylating agent for a hydroxyphenyl dialkylsulfonium compound in the presence of dicyclohexylamine or the like. However, Patent Document 4 does not disclose the superiority of acetate solvents.

Therefore, the present invention relates to a method for producing a compound useful as a curing initiator disclosed in Patent Document 1 with high purity and efficiency.

Unlike the prior art document 1, the present invention reacts a 4-hydroxyphenyldialkylsulfonium compound represented by Chemical Formula ₁ with an acid anhydride represented by R ₁ OR ₁ in the presence of dicyclohexylamine using ethyl acetate as a solvent. In this way, the 4-acyloxyphenyldialkylsulfonium compound represented by Chemical Formula 2 is produced. This method is similar to the second method described in Patent Document 1, except that the reactant is not an acid halide but an acid anhydride, and the amine to be present is not a tertiary amine but dicyclohexylamine. There is a difference in that the solvent is limited to ethyl acetate, and a high-purity compound can be obtained in a high yield from the structural difference.

Wherein R ₁ is an R—CO— group or an R—SO ₂ — group (R is a C ₁ -C ₄ alkyl group optionally substituted with one or more halogens), R ₂ hydrogen, an alkyl group of C ₁ -C _4, or halogen, R ₃ is an alkyl group of C ₁ -C _4, benzyl group, any one of a naphthylmethyl group, R ₄ is C ₁ -C _And X represents SbF ₆ , PF ₆ , or BF ₄ .

Examples of 4-hydroxyphenyldialkylsulfonium compounds represented by Chemical Formula 1, which are raw materials for this reaction, include 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate, 4-hydroxyphenylbenzylmethylsulfonium hexafluoroantimonate, 4-hydroxyphenyl. Examples include dimethylsulfonium hexafluorophosphate, 4-hydroxyphenylmethyl-2-naphthylmethylsulfonium hexafluoroantimonate. Examples of the acid anhydride represented by R ₁ OR ₁ include acetic anhydride, propionic anhydride, butyric anhydride, trifluoroacetic anhydride, methanesulfonic anhydride, and trifluoromethanesulfonic anhydride.

Only dicyclohexylamine is effective as a base to be added for the purpose of neutralizing and removing carboxylic acid and sulfonic acid by-produced after the reaction. The reason for this is not clear, but it is presumed that the amine having steric hindrance controls the reaction by taking in carboxylic acid and sulfonic acid by-produced from the reaction.

Other tertiary amines such as triethylamine and trimethylamine are frequently used in the chemical industry as deoxidizers, but in this reaction, the yield is not improved, which is not preferable. When a strong base such as alkali hydroxide is used as a deoxidizer, hydrogen ions are extracted from the S-CH ₃ moiety to generate iowilide (S = CH ₂ ), or SbF ₆ ions and OH ions are ₅ It is expected that ionic reactions such as (OH) will occur and reduce the yield and purity of the product.

Therefore, amines other than dicyclohexylamine, such as triethylamine, trimethylamine and bases such as alkali hydroxide are not effective in the method of the present invention. The amount of dicyclohexylamine added is 0.9 to 1.1 mol, preferably 0.95 to 1.05 mol, per 1 mol of the raw material sulfonium compound.

Similarly, only ethyl acetate is effective for the solvent. The present invention has been made based on the finding that only ethyl acetate can dissolve and separate only the necessary products without dissolving the by-products of this reaction. Therefore, as described in the examples, after the reaction, by-products can be removed by filtration. Other protic solvents such as benzene, toluenes, DMF, dimethyl sulfoxides, water, methanol and ethanol do not have such advantages.

Further, in the present invention, a 4-hydroxyphenyldialkylsulfonium compound represented by Chemical Formula 3 is dissolved in ethyl acetate and NaSbF ₆ is allowed to act to produce a sulfonium compound represented by Chemical Formula 1 in the solution, A one-pot method is also proposed in which an acid anhydride is reacted with the ethyl acetate solution in the presence of dicyclohexylamine to produce a 4-acyloxyphenyldialkylsulfonium compound represented by Chemical Formula 2.

(Where R ₂ is hydrogen, a C ₁ -C ₄ alkyl group or halogen, R ₃ is a C ₁ -C ₄ alkyl group, benzyl group or naphthylmethyl group, R ₄ is C ₁ -C ₄ alkyl group, Y represents methyl sulfate ion or halogen ion.)

The raw material compound represented by Chemical Formula 3 used here is exemplified by 4-hydroxyphenyldialkylsulfonium chloride or 4-hydroxyphenyldialkylsulfonium methylsulfate in which R ₃ and R ₄ may be the same or different. . Starting from this, an alkali metal salt or ammonium salt of a predetermined acid such as NaSbF ₆ ,
Salt exchange is performed by reacting any one of KSbF ₆ , NaPF ₆ , KPF ₆ , KBF ₄ , and NH ₄ SbF _{6 in} an ethyl acetate solvent.

The solution from which the inorganic substance has been removed is subjected to the reaction described above, that is, by reacting the produced 4-hydroxyphenyldialkylsulfonium compound with an acid anhydride in the presence of dicyclohexylamine. -An acyloxyphenyl dialkylsulfonium compound can be produced. In the present invention, by using ethyl acetate as a solvent, the reaction can be continuously performed only by filtration of by-products.

  Also, the second present invention is different from the prior art in that the 4-acyloxyphenyl dialkylsulfonium represented by the chemical formula 4 is obtained by reacting the 4-acyloxyphenyl alkylsulfide compound represented by the chemical formula 4 with dimethyl sulfate using the acetate ester as a solvent. This is a method for producing a 4-acyloxyphenyldialkylsulfonium compound represented by Chemical Formula 6, characterized in that a compound is obtained, then the sulfonium compound is extracted with water, and a salt represented by MX is allowed to act on the aqueous layer. .

(In the above chemical formulas 4 to 6, etc., R ₁ is an R—CO— group, an R—SO ₂ — group (R is a C _{1 to} C ₄ optionally substituted with one or more halogen atoms). Alkyl group), R ₂ is hydrogen, C ₁ -C ₄ alkyl group, halogen, R ₃ is C ₁ -C ₄ alkyl group, benzyl group, naphthylmethyl group, R ₄ is methyl group, Y is methyl sulfate Ion, M is alkali metal, NH ₄ , X is SbF ₆ , PF ₆ , BF ₄

This method is similar to the methods described in Prior Patent Documents 2 and 3, except that the reactant in the first reaction is limited to dimethyl sulfate, the sulfoniumated solvent is limited to acetate, and the resulting sulfonium compound is Utilizing the water-solubility, the product is purified by extraction with water, and an alkali metal salt or ammonium salt of a predetermined acid represented by MX, such as NaSbF ₆ ,
It is characterized by salt exchange in water by acting any one of KSbF ₆ , NaPF ₆ , KPF ₆ , KBF ₄ , and NH ₄ SbF ₆ . From the structural difference, a compound useful as a curing initiator can be obtained with high purity and high yield without containing impurities such as halogen ions.

Examples of the sulfide compound represented by Chemical Formula 4 that is a raw material for this reaction include 4-acetoxyphenyl methyl sulfide and 4-methanesulfonyloxyphenyl methyl sulfide. The compounds produced by this reaction represented by Chemical Formula 6 include 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenyldimethylsulfonium hexafluorophos Fert, 4-acetoxyphenylmethyl-2-naphthylmethylsulfonium hexafluoroantimonate, 4-methanesulfonyloxyphenyldimethylsulfonium hexafluoroantimonate, 4-methanesulfonyloxyphenylbenzylmethylsulfonium hexafluoroantimonate, 4-methanesulfonyloxy Illustrative is phenyldimethylsulfonium hexafluorophosphate.

As the solvent for this reaction, only acetate esters are effective. Examples of the acetate according to the present invention include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isooctyl acetate, and ethoxyethyl acetate. And only these acetates are made from the knowledge that only the necessary products can be dissolved and separated without dissolving the by-products of this reaction.

Then, as described in the Examples, after the intermediate reaction, the by-product can be separated from the necessary intermediate by a simple operation of extraction with water. Protic solvents such as benzene, toluenes, dimethylformamide, dimethyl sulfoxides, water, methanol, and ethanol other than acetates do not have such advantages as solvents. The addition amount of the acetate may be obtained by dissolving the sulfide compound of Chemical Formula 4 as a solvent.

Further, the reaction temperature in all the inventions according to this specification is preferably 20 ° C. or lower, and particularly preferably 5 ° C. or lower in order to avoid decomposition of the product.

Examples of the first aspect of the present invention are shown below, but the scope of the present invention is not limited thereto.
Example 1
Synthesis of 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate 11.73 g (0.030 mol) of 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate was dissolved in 200 ml of ethyl acetate, and 5.44 g (0,4) of dicyclohexylamine was stirred. 0.030 mol) is mixed, and 3.06 g (0.030 mol) of acetic anhydride is further added dropwise over 3 minutes. Precipitation occurs from the time of dropping. After the addition, the mixture is further stirred for 1 hour. The produced dicyclohexylamine salt is filtered off and the solvent is concentrated to obtain 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate as white crystals. The yield was 11.52 g (yield 88.7%). The purity by high performance liquid chromatography (HPLC) was 99.3%.

Example 2
Synthesis of 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate 5.72 g (0.030 mol) of 4-hydroxyphenyldimethylsulfonium chloride was dissolved in 250 ml of ethyl acetate, and 8.24 g (0.030 mol) of KSbF6 was stirred. Add the powder. The inorganic substance produced by stirring for 1 hour is filtered off. While stirring this solution, 5.44 g (0.030 mol) of dicyclohexylamine is mixed, and 3.06 g (0.030 mol) of acetic anhydride is added dropwise over 5 minutes. Precipitation occurs from the time of dropping. After the addition, the mixture is further stirred for 1 hour. The same treatment as in Example 1 is carried out to obtain 11.09 g (yield 85.4%) of 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate. The purity by high performance liquid chromatography (HPLC) was 99.0%.

Example 3
4. Synthesis of 4-trifluoromethanesulfonyloxyphenyldimethylsulfonium hexafluoroantimonate 11.73 g (0.030 mol) of 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate is dissolved in 200 ml of ethyl acetate and stirred with dicyclohexylamine. 44 g (0.030 mol) is mixed, and 8.46 g (0.030 mol) of trifluoromethanesulfonic anhydride is added dropwise over 5 minutes. Precipitation occurs from the time of dropping. After the addition, the mixture is further stirred for 1 hour. The same treatment as in Example 1 is carried out to obtain 4-crystalline trifluoromethanesulfonyloxyphenyldimethylsulfonium hexafluoroantimonate as white crystals. The yield was 13.11 g (yield 83.6%). The purity by high performance liquid chromatography (HPLC) was 99.4%.

Example 4
Synthesis of 4-propionyloxyphenyldimethylsulfonium hexafluoroantimonate 11.73 g (0.030 mol) of 4-hydroxyphenyldimethylsulfonium hexafluoroantimonate was dissolved in 200 ml of ethyl acetate, and 5.44 g of dicyclohexylamine was stirred. 0.030 mol) is mixed, and 3.90 g (0.030 mol) of propionic anhydride is added dropwise over 3 minutes. Precipitation occurs from the time of dropping. After the addition, the mixture is further stirred for 1 hour. The produced dicyclohexylamine salt of propionate is filtered off and the solvent is concentrated to obtain 4-propionyloxyphenyldimethylsulfonium hexafluoroantimonate as white crystals. The yield was 11.0 g (yield 82.0%). The purity by high performance liquid chromatography (HPLC) was 99.5%.

Comparative Example 1
The same procedure as in Example 1 was conducted except that 3.03 g (0.030 mol) of triethylamine was used instead of dicyclohexylamine. White crystalline 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate is obtained. The yield was 5.69 g (43.8% yield). The purity by high performance liquid chromatography (HPLC) was 98.3%.

Comparative Example 2
Example 1 was carried out except that 200 mL of ethyl acetate was replaced with 200 mL of dimethylformamide as a solvent. Since separation from by-products was not possible, water was added after the reaction was completed, and the product was taken out and recrystallized. 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate is obtained as white slightly yellow crystals. The yield was 8.04 g (yield 61.9%). The purity by high performance liquid chromatography (HPLC) was 97.1%, even after recrystallization.

Comparative Example 3
Example 1 was carried out except that 1.20 g (0.030 mol) of sodium hydroxide was used instead of dicyclohexylamine. White crystalline 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate is obtained. The yield was 2.99 g (yield 23.0%). The purity by high performance liquid chromatography (HPLC) was 96.4%.

The second embodiment of the present invention will be described below.
Reference Example 4-Synthesis of 4-acetoxyphenyl methyl sulfide The 4-acetoxyphenyl methyl sulfide was synthesized according to the method described in French Published Patent No. 2456773. 4.24 g (0.03 mol) of 4-hydroxyphenylmethyl sulfide and 3.37 g (0.033 mol) of acetic anhydride were mixed and stirred while cooling, and when 3 drops of concentrated sulfuric acid was added thereto, an exothermic reaction started. did. After stirring for 2 hours, excess acetic anhydride was removed by distillation. After allowing to stand overnight and cooling, the solid was recrystallized with hexane to obtain 4.26 g of 4-acetoxyphenyl methyl sulfide. Yield 75.4%

Example 5
Synthesis of 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate 5.65 g (0.030 mol) of 4-acetoxyphenylmethylsulfide synthesized in Reference Example was dissolved in 100 ml of ethyl acetate, and 3.78 g ( 0.030 mol) is added dropwise in 3 minutes. Precipitation occurs from the time of dropping. After the addition, the mixture is further stirred for 1 hour. Thereafter, 50 mL of water is added, and the product 4-acetoxyphenyldimethylsulfonium methyl sulfate is transferred to the aqueous layer by vigorously stirring for 3 minutes. The aqueous layer is separated, and 50 mL of an aqueous solution of 7.7 g (0.030 mol) of NaSbF ₆ is added dropwise over 10 minutes to obtain 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate as white crystals. The yield was 12.03 g (yield 92.6%). The purity by high performance liquid chromatography (HPLC) was 99.3%.

Example 6
Example 5 was performed except that 100 mL of butyl acetate was used instead of ethyl acetate. White crystalline 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate is obtained. The yield was 11.78 g (90.7% yield). The purity by high performance liquid chromatography (HPLC) was 99.3%.

Example 7
Synthesis of 4-methanesulfonyloxyphenyldimethylsulfonium hexafluoroantimonate 6.55 g (0.030 mol) of 4-methanesulfonyloxyphenyl methylsulfide was dissolved in 100 ml of ethyl acetate, and 3.78 g (0 0.030 mol) is added dropwise in 3 minutes. Precipitation occurs from the time of dropping. After the addition, the mixture is further stirred for 1 hour. Thereafter, 50 mL of water is added, and the product, 4-methanesulfonyloxyphenyldimethylsulfonium methyl sulfate, is transferred to the aqueous layer by vigorously stirring for 3 minutes. The aqueous layer is separated, and 50 mL of an aqueous solution of 7.7 g (0.030 mol) of NaSbF ₆ is added dropwise thereto over 10 minutes to obtain 4-methanesulfonyloxyphenyldimethylsulfonium hexafluoroantimonate. The yield was 12.48 g (yield 88.7%). The purity by high performance liquid chromatography (HPLC) was 99.0%.

Comparative Example 4
Example 5 was performed except that 100 mL of toluene was used instead of ethyl acetate. White crystalline 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate is obtained. The yield was 5.69 g (43.8% yield). The purity by high performance liquid chromatography (HPLC) was 98.3%.

Comparative Example 5
The procedure was as in Example 5, except that 100 mL of methylene chloride was used instead of ethyl acetate. 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate having slightly yellowish white crystals is obtained. The yield was 10.29 g (yield 79.2%). The purity by high performance liquid chromatography (HPLC) was 95.0%.

As apparent from the examples, according to the method for producing a dialkylsulfonium compound of the present invention, a sulfonium salt used as an epoxy curing initiator that requires high purity can be produced by a simple method.

Claims (3)

A 4-hydroxyphenyldialkylsulfonium compound represented by Chemical Formula ₁ and an acid anhydride represented by R ₁ OR ₁ are reacted in the presence of dicyclohexylamine using ethyl acetate as a solvent. A method for producing a 4-acyloxyphenyldialkylsulfonium compound.
(Where R ₁ is an R—CO— group, an R—SO ₂ — group (R is a C ₁ -C ₄ alkyl group optionally substituted with one or more halogens), and R ₂ is hydrogen, an alkyl group of C ₁ -C _4, halogen, R ₃ is an alkyl group of C ₁ -C _4, benzyl group, naphthylmethyl group, R ₄ is a is .X alkyl group C ₁ -C ₄ SbF ₆ , PF ₆ and BF ₄ are shown.)

A 4-hydroxyphenyldialkylsulfonium compound represented by Chemical Formula 3 is dissolved in ethyl acetate to act on a salt represented by MX, and then the ethyl acetate solution is represented by R ₁ OR ₁ in the presence of dicyclohexylamine. A method for producing a 4-acyloxyphenyldialkylsulfonium compound represented by Chemical Formula 4, wherein an acid anhydride is reacted.
Wherein R ₁ is an R—CO— group or an R—SO ₂ — group (R is a C ₁ -C ₄ alkyl group optionally substituted with one or more halogens), R ₂ hydrogen, an alkyl group of C ₁ -C _4, or halogen, R ₃ is an alkyl group of C ₁ -C _4, benzyl group, any one of a naphthylmethyl group, R ₄ is C ₁ -C ₍ M is an alkali metal, NH ₄ , X is SbF ₆ , PF ₆ , BF ₄ , and Y is a methyl sulfate ion or a halogen ion.)

The 4-acyloxyphenyl alkylsulfide compound represented by Chemical Formula 5 is reacted with dimethyl sulfate using an acetic ester as a solvent to form a 4-acyloxyphenyldialkylsulfonium compound represented by Chemical Formula 6, which is then extracted with water, A method for producing a 4-acyloxyphenyldialkylsulfonium compound represented by Chemical Formula 7, wherein a salt represented by MX is allowed to act on the layer.
Wherein R ₁ is an R—CO— group, an R—SO ₂ — group (R is a C ₁ -C ₄ alkyl group optionally substituted with one or more halogens), R ₂ is hydrogen, an alkyl group of C ₁ -C _4, halogen, R ₃ is an alkyl group of C ₁ -C _4, benzyl group, naphthylmethyl group, R ₄ is a methyl group, Y is methyl sulfate ion, M is an alkali metal , NH ₄ , X represents SbF ₆ , PF ₆ , BF _4. )