JPS61212554A - Production of aromatic sulfonium salt - Google Patents

Abstract

PURPOSE:To obtain a compound useful as a cationic polymerization initiator, etc., having improved photosensitive properties, by a simple operation in high purity in high yield, by reacting a specific aromatic sulfide compound with a sulfoxide compound in sulfuric acid. CONSTITUTION:An aromatic sulfide compound containing at least two benzene nuclei directly bonded by a sulfide bond and hydrogen bonded to at least one p-position of the benzene nuclei is reacted with a sulfoxide compound shown by the formula I (R1 and R2 are aliphatic or aromatic group, which may be bonded to form ring) in sulfuric acid at room temperature to give the aimed substance. The aimed substance is a sulfate or hydrogensulfate of an aromatic sulfonium containing a sulfonio group shown by the formula II at the para- position to which hydrogen of at least one benzene nucleus of the aromatic sulfide compound is bonded. The amount of the sulfuric acid used is >= an equimolar amount, preferably >= three times the molar amount of the compound shown by the formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing aromatic sulfonium salts. More specifically, the present invention relates to a method for producing aromatic sulfonium salts in high yield through simple operations.

[Conventional technology and problems]

Aromatic sulfonium salts have excellent photosensitivity and are therefore used as cationic polymerization initiators. In particular, those that combine with sulfur atoms to form sulfonium and have a diphenyl sulfide skeleton in one group have a wavelength of 3.
It has absorption at 00 mμ or more and exhibits excellent photosensitivity.

However, such methods for producing aromatic sulfonium salts are generally not easy, and there is a need for a method for producing aromatic sulfonium salts in high yield through simple operations.

An excellent production method is disclosed in JP-A-55-125105, in which diphenyl sulfide is reacted with chlorine gas in the presence of a large amount of Friedel's catalyst to obtain bis-[4-(diphenylsulfonio)phenyl]sulfide dichloride. However, this production method has the disadvantages that the method for isolating the target compound is complicated, that the purity and yield are poor, and that the yield is not acceptable.

An object of the present invention is to provide a method for producing aromatic sulfonium salts in high yield and purity (by simple operations).

[A quick way to solve problems]

In order to achieve the above object, the method of the present invention has at least two benzene nuclei directly bonded by a sulfide bond, and a hydrogen atom is bonded to at least one para-position of the benzene nucleus (formula In sulfuric acid, R1 and R2 are aliphatic groups, and R1 and R2 are aromatic groups, which may be bonded to each other to form a ring, in sulfuric acid to form a sulfonio group. The present invention is characterized by obtaining a sulfate or hydrogen sulfate of aromatic sulfonium introduced at the para-position to which the hydrogen atom of at least one benzene nucleus of the aromatic sulfide compound was bonded.

The above-mentioned aromatic sulfide compound has two benzene nuclei that are directly bonded by a sulfide bond, and a hydrogen atom is bonded to at least one para-position of the benzene nucleus. , other places 1f/
Ii Various atoms and substituents: e.g. halogen, nitro group,
Two benzene nuclei that may be substituted with atoms or substituents that are stable under acidic conditions such as alkyl groups, thiophenoxy groups, phenoxy groups, alkoxy groups, sulfone groups, etc. Value groups, e.g. -〇-
, -S-.

(2) It may be further bonded with -C-, C-middle group, etc. to form a ring containing a sulfide bond. Furthermore, in addition to aromatic sulfide compounds that can be used in the present invention, sulfonium groups,
There is no problem even if it has an onium salt structure such as an ammonium group. Specific examples of such aromatic sulfide compounds include the following.

R, , R2 are aliphatic groups or aromatic groups, and may be bonded to each other to form a ring). R12 is, for example, an alkyl group such as methyl, ethyl, propyl, butyl, a cycloalkyl group such as cyclohexyl, an allyl group such as phenyl, tolyl, naphthyl, anthryl, or alkoxy, alkyl, nitro, halogen, hydroxy, etc. Substituted groups such as aromatic heterocyclic groups such as pyridyl and furfuryl, such as benzyl and phenylacyl groups, such as tetramethylene groups formed by bonding with R, R2, etc., are mentioned. Specific examples of such compounds include the following.

The concentration of sulfuric acid used is preferably 20% or more, more preferably 50% or more.

The amount of sulfuric acid used is at least equimolar, preferably at least 3 times the molar amount of the sulfoxide compound represented by the above general formula (13).

The ratio of the aromatic sulfide compound and the sulfoxide compound represented by the general formula (1) can be selected relatively freely depending on whether the aromatic sulfonium salt to be obtained is a mono-sulfonium salt or a polysulfonium salt. I can do it. The order of charging the raw materials is usually to mix the sulfoxide compound and sulfur rR, then drop the aromatic sulfide compound (however, in some cases, for example, after charging the aromatic sulfide compound and the sulfoxide compound, filE+[
- Dropwise addition method t Very good The reaction between the aromatic sulfide compound and the sulfoxide compound proceeds quickly in sulfuric acid and is completed within a few minutes to a few hours even at room temperature without the need for particular heating. Since the reaction generally generates heat, it is preferable to cool the reaction in some cases. The treatment method after the completion of the reaction varies depending on the properties of the sulfonium salt obtained. If the water solubility of the sulfonium salt is low, it can be recovered as a precipitate by pouring it into the reaction mixture Wt-water, or the anion portion of the sulfonium salt can be used as a photosensitive polymerization catalyst with PF6. AIIF6. If you want to change to a less nucleophilic anion such as SbF, salt, etc., you can directly convert the reaction mixture into a water-bathable salt or acid having these structures (for example, Na5bF6.KPF6.KAIIF6.HP
An aromatic sulfonium salt having a desired anion structure can be obtained by pouring it into an aqueous solution containing 1-F, etc.). These sulfonium salts are generally a-soluble in water and well soluble in polar organic solvents, so they can be easily recovered.

The aromatic sulfonium salt obtained in the present invention has a sulfonio group represented by the above-mentioned aromatic sulfide compound (from an aromatic sulfonium sulfate having a para-IC to which one hydrogen atom of a benzene nucleus is bonded). When hydrogen sulfate is used on an aromatic sulfide compound that has several layers of a structure in which a hydrogen atom is bonded to the para-position of a benzene nucleus bonded to the p1 sulfur atom, each para of the several benzene nuclei is Companions by introducing the above-mentioned sulfonio group into the - position can also be obtained according to the present invention.

〔Effect of the invention〕

The advantage of the present invention is that it provides a method for producing aromatic sulfonium salts with high yield and purity through simple operations. Furthermore, according to the method of the present invention, a &-substituted sulfonium salt can be easily obtained by using a sulfoxide compound having a desired substituent as a raw material. The subsulfonium salt obtained by the method of the present invention exhibits excellent photosensitivity without special purification.

〔Example〕

The effectiveness of the present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples as long as it does not go beyond the gist of the invention (Example 1 Diphenylsulfoxide (a, 1g)
Diphenyl sulfide (1,89) was added dropwise to this liquid over 2 minutes. After that, stirring was continued for 1 hour at room temperature, and the reaction mixture changed from deep blue to transparent with a slight pinkish tinge. The reaction mixture was then poured into an aqueous solution of KPF6, yielding a white solid. When recrystallized once from methanol, 7.69 crystals were obtained.

By comparing this crystal with known compounds, it was found that bis-
It was confirmed that it was [4-(diphenylsulfonio]phenyl]sulfide bishexafluorophosphate. The purity was also 98% or more.

A similar sulfonium salt produced by the method described in JP-A-55-125105 had a yield of less than 50% and a purity of less than 70%, making it difficult to purify by tp recrystallization.

Example 2 4.4' Difluorophenyl sulfonate (909) was dissolved in sulfuric acid C40C40O, and diphenyl sulfide (59,11) was added dropwise while cooling in a water bath. After the completion of the dropwise addition, the reaction mixture was dissolved in 6 containing 9090KPF6. % aqueous solution to give a white color (1701). Recrystallized from methylene chloride/ethanol and having a melting point of 22Q°C, a-NMR,
IR (f) This crystal was confirmed to be 4,4/-bis[bis(p-fluorophenyl]sulfonio]phenylsulfide bisshekitefluorophosphate.

This example shows that aromatic sulfonium salts having t substituents can also be easily obtained in high yield and high purity according to the method of the present invention.

Example 5 A sulfuric acid (20 mt) was added to a mixture of diphenyl sulfide (5,0Ii) and dimethyl sulfoxide (6,0#).
was dripped. When the obtained milky white solution was poured into an aqueous solution containing KPF6, a white solid (9,On) was precipitated. This solid was recrystallized from acetone/ethanol and had a melting point of 176-7°C.
Needle-shaped crystals were obtained. This compound was analyzed by O-NMR (TMS)
Internal standard, DM30-(16 in ppm);
14tl, 2,131.8, 130.9°125.9
, 28.1), 'I(-NMR(TMB internal cotton')
$1.

0M80-(16 in (ppm); 8,05(4)1
), 7, 62 (4H).

3.25 (12H)], bis[4
-(Dimethylsulfonio]phenyl]sulfide bishexafluorophosphate was confirmed.

Claims (1)

[Scope of Claims] An aromatic sulfide compound having at least two benzene nuclei directly bonded through a sulfide bond, and a hydrogen atom bonded to at least one para-position of the benzene nucleus, and the general formula : ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (In the formula, R_1 and R_2 are aliphatic groups or aromatic groups and may be bonded to each other to form a ring.) is reacted in sulfuric acid and the sulfonio group represented by the general formula: ▲There are mathematical formulas, chemical formulas, tables, etc. 1. A method for producing an aromatic sulfonium salt, which comprises obtaining a sulfate or hydrogen sulfate of an aromatic sulfonium having a hydrogen atom at the para-position.