CN103980181B - Triarylsulfonium salt containing 1-methyl-2-phenylindone skeleton and preparation method thereof - Google Patents

Abstract

The present invention relates to an aromatic sulfonium salt compound, in particular to a triarylsulfonium salt containing a 1-methyl-2-phenylindole skeleton and a preparation method and application thereof. The method is based on 1-methyl-2-phenylindole As a raw material, diphenyl disulfide is used as a sulfur source to carry out a C-S bond coupling reaction to synthesize an aromatic sulfide, and then react with a diaryliodonium salt under copper-catalyzed conditions to prepare it; the ultraviolet absorption wavelength of this type of compound The range can be broadened and can be red-shifted to above 290nm. It can be used as a cationic photoinitiator for UV-curable compositions, especially in UV-curable coatings, and has good reactivity, surface curing ability and solubility. 1-Methyl- The introduction of this special group of 2-phenylindole effectively improved its photoinitiation performance.

Description

Triarylsulfonium salt containing 1-methyl-2-phenylindole skeleton and preparation method thereof

technical field

The present invention relates to a triaryl sulfonium salt, specifically a triaryl sulfonium salt containing a 1-methyl-2-phenylindole skeleton and a preparation method thereof, and the salt is used as a photoinitiator in an ultraviolet light curing composition, especially It is used in UV curing coatings.

Background technique

Photocuring technology is a rapidly developing green new technology. The photocuring system is generally composed of unsaturated resin, reactive diluent, photoinitiator and auxiliary agent. Among them, the photoinitiator is the key component, which generates active free radicals or cations after absorbing ultraviolet light, triggers the double bond opening polymerization of the unsaturated group in the resin, and the ring-opening polymerization of the epoxy resin to quickly cure and form a film. Compared with free radical photoinitiators, although the curing speed of cationic photoinitiators is slow, the shrinkage rate of the coating after curing is small, and the comprehensive properties such as adhesion are better. It is well known that cobalt salts can be used as initiators of cationic polymerization in curing systems, but in practical applications, there are disadvantages of low solubility and the formation of small molecules (such as benzene and diphenyl sulfide) due to C-S bond breakage during curing radiation. Therefore, the development of a new type of columium salt photoinitiator, which has the advantages of excellent solubility, low mobility, and small benzene release, has aroused the interest of many scholars. The present invention starts from simple and easy-to-obtain raw materials, and synthesizes cationic triarylsulfonium salts with strong conjugation degree, maximum ultraviolet absorption above 290nm, and low migration indole ring by a simple method.

Contents of the invention

The object of the present invention is to provide a kind of triaryl sulfonium salt containing 1-methyl-2-phenylindole skeleton and preparation method thereof, and the salt is used as a photoinitiator in UV-curable compositions, especially UV-curable coatings in the application. As a photoinitiator, the compound has the characteristics of low odor, low mobility and fast curing speed.

A kind of triaryl sulfonium salt containing 1-methyl-2-phenylindole skeleton provided by the present invention, its structural formula is:

A kind of preparation method that contains the triaryl sulfonium salt of 1-methyl-2-phenylindole skeleton provided by the invention, comprises the steps:

1) Add 1-methyl-2-phenylindole and diphenyl disulfide into the reactor, add DMSO to dissolve them, then add cuprous iodide, heat up to 110°C, react for 2.5 hours, and transfer to Liquid funnel, separated the organic layer, washed the organic layer with distilled water, dried with anhydrous sodium sulfate, filtered, spin-dried the solvent, and separated by column chromatography to obtain 1-methyl-2-phenyl-3-phenylsulfide ind Indole;

2) Add 1-methyl-2-phenyl-3-phenylsulfide indole and diaryl iodide trifluoromethanesulfonate into the reactor, and use 1,1,2,2-tetrachloroethane Or dimethyl sulfoxide or N,N-dimethylformamide (preferably 1,1,2,2-tetrachloroethane) after dissolving it, add cuprous iodide and copper powder, heat up to 100-130 °C (preferably 110 °C), reacted for 3 hours, returned to room temperature, monitored by TLC, and separated by column chromatography to obtain the target product diaryl-[3-(1-methyl-2-phenyl)indole]sulfonium tri Flate.

The diaryl iodide triflate is diphenyl iodide triflate or bis-(4-tolyl) iodine triflate.

The molar ratio of the 1-methyl-2-phenyl-3-phenylsulfide indole, diaryl iodide trifluoromethanesulfonate, cuprous iodide and copper powder is 1: 1.1: 0.1: 0.05.

This type of compound contains 1-methyl-2-phenylindole group, and its conjugation degree is relatively high, and the ultraviolet absorption wavelength is red-shifted to 295nm, which is higher than the ultraviolet absorption wavelength of general triarylsulfonium salts.

The application of the triarylsulfonium salt containing 1-methyl-2-phenylindole group skeleton as photoinitiator in ultraviolet light curing composition, especially ultraviolet light curing coating.

The photocurable composition provided by the present invention contains the triarylsulfonium salt with the above-mentioned structure containing 1-methyl-2-phenylindole skeleton.

In the present invention, the triarylsulfonium salt containing 1-methyl-2-phenylindole skeleton is applied to the photocurable composition, which not only has good reactivity, surface curing ability and solubility, but also has indole in the molecule The group has a high degree of molecular conjugation, which effectively increases the range of ultraviolet absorption and reduces the release of benzene.

Description of drawings

Figure 1 UV spectrum of diphenyl-(1-methyl-2-phenylindole)sulfonium trifluoromethanesulfonate I

Figure 2 The H NMR spectrum of diphenyl-(1-methyl-2-phenylindole)sulfonium trifluoromethanesulfonate I

Figure 3 UV spectrum of phenyl-(4-methylbenzene)-(1-methyl-2-phenylindole)sulfonium trifluoromethanesulfonate II

Figure 4 The H NMR spectrum of phenyl-(4-methylbenzene)-(1-methyl-2-phenylindole)sulfonium trifluoromethanesulfonate II

detailed description

Example 1

Put a magnetic stirring bar in a two-necked flask equipped with a condenser, add diphenyl disulfide (1.1mmol) and 1-methyl-2-phenylindole (2mmol) respectively, drop DMSO until just dissolved, Cuprous iodide (0.1 mmol) was added, and the temperature was raised to 110° C., followed by reaction for 6 hours. After the reaction, the solvent was removed by rotary evaporation, and column chromatography was carried out to obtain 1-methyl-2-phenyl-3-phenylindole sulfide as white crystals. The yield was 78%, and the melting point was 102- 104°C. 1HNMR (300MHz, CDCl3): 3.75(s, CH3, 3H), 7.01-7.19(m, ArH, 7H), 7.22-7.26(m, ArH, 1H), 7.32-7.37(m, ArH, 5H), 7.41 (m, ArH, 1H).

Example 2:

A magnetic stirring bar was placed in a two-necked flask equipped with a condenser, and diphenyl iodide trifluoromethanesulfonate (1.1 mmol) and 1-methyl-2-phenyl-3-phenylsulfide ind Indole (1mmol), add 1,1,2,2-tetrachloroethane dropwise until just dissolved, then add cuprous iodide (0.1mmol), copper powder (0.05mmol), rise to 110°C, react for 2.5 hours . After the reaction liquid was cooled to room temperature, the solvent was spun off, and the mixture was subjected to column chromatography using dichloromethane and ethyl acetate as eluents successively to obtain compound (I) as white crystals.

Compound (I): white crystals, yield 61.3%, melting point 204-205°C. See Figure 1 for the UV spectrum; see Figure 2 for the H NMR spectrum; ¹ HNMR (300MHz, CDCl ₃ ): 3.83(s, N-CH ₃ , 3H), 7.17～7.19(m, ArH, 4H), 7.22～7.44(m , ArH, 5H), 7.45-7.64 (m, ArH, 5H), 7.67-7.73 (m, ArH, 5H).

Example 3:

A magnetic stirrer was placed in a two-necked flask equipped with a condenser, and bis-(4-methylphenyl)iodotrifluoromethanesulfonate (1.1 mmol) and 1-methyl-2-phenyl-3- Phenylsulfide indole (1mmol), add 1,1,2,2-tetrachloroethane dropwise until just dissolved, then add cuprous iodide (0.1mmol), copper powder (0.05mmol), raise to 110°C Afterwards, react for 2.5 hours. After the reaction, the solvent was spun off, and the mixture was sequentially separated by column chromatography using dichloromethane and ethyl acetate as eluents to obtain compound (II) as pale yellow crystals.

Compound (II): Pale yellow crystal, yield 62.0%, melting point 174-176°C. See Figure 3 for the UV spectrum; H NMR spectrum 4: ¹ HNMR (600MHz, CDCl ₃ ): 2.47(s,-CH ₃ ,3H), 3.84(s,N-CH ₃ ,3H), 7.00～7.22(m, ArH, 4H), 7.23-7.45 (m, ArH, 4H), 7.46-7.51 (m, ArH, 5H), 7.55-7.65 (m, ArH, 5H).

The following examples are the curing performance of compound (I) or compound (II) of the present invention as cationic photoinitiator and the comparison with the curing performance of commercially available free radical photoinitiator 184: wherein the oligomer used is modified Epoxy acrylate (UV1005-65 produced by Zhongshan Qianfeng Chemical Factory), the monomer is 1,6-hexanediol diacrylate (produced by HDDA Zhongshan Qianfeng Chemical Factory).

Example 4: Application performance evaluation of diphenyl-[3-(1-methyl-2-phenyl)indole]sulfonium trifluoromethanesulfonate (I)

Experimental formula:

working conditions

Under the condition of avoiding light, add 0.03g of photoinitiator, UV1005-650.5g, HDDA0.45g, and triethanolamine 0.02g into the glass container, and stir evenly until the coating liquid becomes transparent. The mixture was coated on a glass plate with an applicator to form a film, the film thickness was 100um, and it was irradiated and cured in a medium-pressure mercury lamp, and the power of the mercury lamp was 400W.

Example 5: Application performance evaluation of phenyl-(4-methylbenzene)-[3-(1-methyl-2-phenyl)indole]sulfonium trifluoromethanesulfonate (II)

Experimental formula:

Working condition is the same as embodiment 4

Embodiment 6 (comparative example): the application performance evaluation of photoinitiator 184

Experimental formula:

Working condition is the same as embodiment 4

Example 7: Application performance evaluation of [3-(1-methyl-2-phenyl)indole]-diphenylsulfonium trifluoromethanesulfonate sulfonium(II) and 184 ratio of 1:1

Test formula:

Under light-shielding conditions, add 0.03g of the photoinitiator mixture of compound (II) of the present invention and 184 ratio of 1:1, UV1005-650.5g, HDDA0.45g, triethanolamine 0.02g in a glass container, and stir evenly to Transparent coating liquid. The mixture was coated on a glass plate with an applicator to form a film, the film thickness was 100um, and it was irradiated and cured in a medium-pressure mercury lamp, and the power of the mercury lamp was 400W.

Example 8: Application performance evaluation of [3-(1-methyl-2-phenyl)indole]-diphenylsulfonium trifluoromethanesulfonate (II) and 184 at a ratio of 1:2

Test formula:

Under light-shielding conditions, add 0.03g of the photoinitiator mixture of compound (II) of the present invention and 184 ratio of 1:2, UV1005-650.5g, HDDA0.45g, triethanolamine 0.02g in the glass container, stir evenly to Transparent coating liquid. The mixture was coated on a glass plate with an applicator to form a film, the film thickness was 100um, and it was irradiated and cured in a medium-pressure mercury lamp, and the power of the mercury lamp was 400W.

Carry out performance test to the coating film of above-mentioned embodiment 4-8 composition:

a Surface dry time test: refers to dry method or cotton ball method.

b Hardness test: Pencil hardness test according to GB/T6739-1996. Use a coating film pencil scratch hardness tester to observe the scratch marks on the paint film, and take the pencil without scratches as the pencil hardness of the coating film.

c Adhesion test: cross-hatch method determination (refer to GB9286-88). The adhesion of the coating film was judged by the cross-hatch test method. According to the degree of damage, it can be divided into 6 grades from 0 to 5. The best grade is 0, no small cells on the membrane surface have fallen off, and grade 5 is extremely poor, and the membrane surface has severe peeling.

The evaluation results are shown in Table 1.

Table 1 Compound (I), compound (II) and the comparison of 184 application properties

As can be seen from the test results in the above table: the triarylsulfonium salt compound (I) and compound (II) provided by the present invention containing 1-methyl-2-phenylindole skeleton are all excellent in terms of curing speed and film-forming hardness. commercially available free radical photoinitiator 184. When the compound (II) of the present invention is used in combination with 184, the comprehensive properties such as adhesion are improved, which further broadens the application of 184 in epoxy resins.

Claims (7)

1. the triarylsulfonium salt containing 1-methyl-2-phenylindone skeleton, it is characterized in that, structural formula is:

2. the preparation method of a kind of triarylsulfonium salt containing 1-methyl-2-phenylindone skeleton as claimed in claim 1, is characterized in that, comprise the steps:

1) 1-methyl-2-phenylindone, diphenyl disulfide are added in reactor, add after DMSO is dissolved and add cuprous iodide again, be warming up to 110 DEG C, react 2.5 hours, proceed to separating funnel, isolate organic layer, use distilled water wash organic layer, with anhydrous sodium sulfate drying, filter, be spin-dried for solvent, column chromatography for separation, obtain 1-methyl-2-phenyl-3-aralkyl sulfid indoles;

2) 1-methyl-2-phenyl-3-aralkyl sulfid indoles, Diaryl iodonium fluoroform sulphonate are added in reactor, with 1,1,2,2-tetrachloroethane or dimethyl sulfoxide (DMSO) or N, after dinethylformamide is dissolved, add cuprous iodide and copper powder, be warming up to 100-130 DEG C, react 3 hours, return to room temperature, by TLC monitoring, column chromatography for separation, obtain object product [3-(1-methyl-2-phenyl) indoles]-diaryl sulfonium fluoroform sulphonate.

3. preparation method as claimed in claim 2, it is characterized in that, the mol ratio of 1-methyl-2-phenyl-3-aralkyl sulfid indoles, Diaryl iodonium fluoroform sulphonate, cuprous iodide and copper powder in described step (2) is 1 ︰ 1.1 ︰ 0.1 ︰ 0.05.

4. preparation method as claimed in claim 2, it is characterized in that, the solvent in described step (2) is sym.-tetrachloroethane.

5. preparation method as claimed in claim 2, it is characterized in that, the temperature of reaction in described step (2) is 110 DEG C.

6. a kind of application of triarylsulfonium salt as light trigger containing 1-methyl-2-phenylindone skeleton as claimed in claim 1.

7. a compositions of ultraviolet curing type, is characterized in that, containing the triarylsulfonium salt containing 1-methyl-2-phenylindone skeleton according to claim 1.