Diaryl thioether photoinitiator as well as preparation method and application thereof

Abstract

The invention relates to a diaryl thioether photoinitiator as well as a preparation method and application thereof, an aryl thioether photocompound is prepared by reacting substituted benzene with sulfur chloride, and the preparation method specifically comprises the following steps: reacting a substituted benzene compound with S2Cl2 to synthesize an intermediate diaryl thioether compound; the preparation method comprises the following steps: reacting diaryl sulfide with parachlorobenzophenone or parachlorophenyl aminoketone, and synthesizing to obtain an aryl sulfide benzophenone compound or an aryl sulfide alpha-aminoketone compound; according to the synthesis method, thiophenol with stink is not used, and the preparation process is green and environment-friendly and is easy to industrialize; the synthesized compound can be used as a photoinitiator and shows a better photocuring effect.

Description

Technical Field

[0001] The invention relates to an organic polymer compound, a photoinitiator for a polymerization process, and belongs to the field of photocurable materials, in particular to a diaryl sulfide photoinitiator, a preparation method and application thereof. Background Art

[0002] UV curing technology offers five advantages and is widely used in printing, packaging, building materials, medical treatment, electronics, communications, and other fields. A UV polymerization system generally consists of a photoinitiator, oligomers, monomers, and additives. While the photoinitiator content is typically 3% to 5%, it plays an irreplaceable role and is a key factor influencing the curing speed. A photoinitiator is a compound that absorbs energy of a specific wavelength in the ultraviolet (250-420 nm) or visible (400-800 nm) region to generate free radicals, cations, and other molecules, thereby initiating polymerization and cross-linking of the monomers.

[0003] Diaryl sulfide benzophenone initiators, represented by 4-benzoyl-4'-methyl-diphenyl sulfide, are used in combination with photoinitiators ITX and EDB for pigmented paint systems. They have good solubility, good miscibility with liquid photosensitizers, and low odor, and are also suitable for white paints, varnishes, and colored systems.

[0004] The common method for introducing aromatic thio groups is to use substituted thiophenols to undergo nucleophilic substitution reaction under the action of base, but thiophenol or substituted thiophenols have a strong odor, seriously polluting the environment and affecting the physical and mental health of experimenters.

[0005] Chinese invention patent CN111187188A discloses a method for synthesizing diaryl sulfides and their thiophenols. This method uses sulfonyl chloride as a raw material and requires the use of SO₂ gas, a major atmospheric pollutant, under nitrogen protection. The process is complex. Therefore, a green and industrially scalable method for producing aryl sulfides is needed.

[0006] Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a diaryl sulfide photoinitiator and a preparation method and application thereof.

[0008] The technical solution adopted by the present invention is: a diaryl sulfide photoinitiator, the structure of which is shown in Formula IV or Formula VI;

[0009] ;

[0010] ;

[0011] Wherein, R1-R5 can be independently selected from H or C1-C5 alkyl, alkoxy, alkylthio, dialkylamino, and R1-R5 can be the same, partially the same or different.

[0012] Preferably, the structure is as shown in any one of Formulas IVa, IVb, IVc, VIa, VIb and VIc.

[0013] , , , , , .

[0014] The invention discloses a method for preparing a diaryl sulfide photoinitiator, comprising reacting a substituted benzene compound with sulfur chloride to obtain an intermediate diaryl sulfide compound; and then reacting the intermediate diaryl sulfide compound with p-chlorobenzophenone or p-chlorophenylaminoketone to obtain a diaryl sulfide photoinitiator of formula IV or formula VI.

[0015] Preferably, the specific preparation method is as follows:

[0016] Step 1: reacting a substituted benzene compound represented by Formula I with S2Cl2 to synthesize a diaryl sulfide compound represented by Formula II;

[0017] , ;

[0018] Wherein, R1-R5 can be independently selected from H or C1-C5 alkyl, alkoxy, alkylthio, dialkylamino, and R1-R5 can be the same, partially the same, or different;

[0019] Step 2: reacting the diaryl sulfide compound represented by formula II with p-chlorobenzophenone to synthesize the aryl sulfide benzophenone compound represented by formula IV;

[0020] Alternatively, the diaryl sulfide compound represented by formula II is reacted with p-chlorophenyl aminoketone to synthesize the aryl sulfide α-aminoketone compound represented by formula VI.

[0021] Preferably, in step 1, the substituted benzene compound and S2Cl2 are dissolved in a first solvent, or S2Cl2 is dissolved in a substituted benzene solvent, and a Lewis acid is used as a catalyst to react at room temperature or low temperature to obtain an intermediate diaryl sulfide compound;

[0022] Preferably, the Lewis acid catalyst is ZnCl2, AlCl3, FeCl3 or SnCl4;

[0023] The first solvent is dichloromethane, dichloroethane, chloroform or glacial acetic acid.

[0024] Preferably, in step 2, the intermediate diaryl sulfide compound represented by formula II and p-chlorobenzophenone are dissolved in a second solvent, a base is added, and the reaction is carried out at 50-120° C. After removing the organic solvent, the product is added to water, extracted with ethyl acetate, and recrystallized to obtain the aryl sulfide benzophenone compound represented by formula IV;

[0025] Preferably, the second solvent is one or more of dichloromethane, dichloroethane, chloroform, acetone, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone;

[0026] The base is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride or potassium hydride;

[0027] The molar ratio of the compound of formula II to p-chlorobenzophenone is 0.5:1 to 1:1.

[0028] Preferably, in step 2, the intermediate diaryl sulfide compound represented by formula II and p-chlorophenyl aminoketone are dissolved in a third solvent, a base is added, and the reaction is carried out at 50-120° C. After removing the organic solvent, the product is added to water, extracted with ethyl acetate, and recrystallized to obtain the aryl sulfide α-aminoketone compound represented by formula VI;

[0029] Preferably, the third solvent is one or more of dichloromethane, dichloroethane, chloroform, acetone, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone;

[0030] The base is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride or potassium hydride;

[0031] The molar ratio of the compound of formula II to p-chlorobenzophenone is 0.5:1 to 1:1.

[0032] Application of diaryl sulfide photoinitiators in photocuring.

[0033] Preferably, the diaryl sulfide photoinitiator is mixed with the resin and the co-initiator, and curing is achieved after irradiation with ultraviolet light.

[0034] The advantages and positive effects of the present invention are: providing a new preparation method of a diaryl sulfide photoinitiator, avoiding the use of odorous thiophenol, the preparation process is green and environmentally friendly, and easy to industrialize; the prepared diaryl sulfide photoinitiator can be used to initiate resin photocuring and exhibits better photocuring effect. DETAILED DESCRIPTION

[0035] The solution of the present invention is described below.

[0036] In one aspect, the present invention provides a diaryl sulfide photoinitiator and a method for preparing the same. The diaryl sulfide photoinitiator compound structure is shown in Formula IV or Formula VI;

[0037] ;

[0038] ;

[0039] Wherein, R1-R5 can be independently selected from H or C1-C5 alkyl, alkoxy, alkylthio, dialkylamino, and R1-R5 can be the same or different.

[0040] Another aspect of the present invention provides a method for preparing a diaryl sulfide photoinitiator, wherein an aryl sulfide photoinitiator is prepared by reacting substituted benzene with sulfur chloride. The chemical reaction equation is as follows:

[0041]

[0042] The specific preparation method is as follows:

[0043] Step 1: reacting a substituted benzene compound represented by Formula I with S2Cl2 to synthesize a diaryl sulfide compound represented by Formula II; dissolving the substituted benzene compound and S2Cl2 in a first solvent at a molar ratio of 2:1, or dissolving S2Cl2 in a substituted benzene solvent, using a Lewis acid as a catalyst, reacting at room temperature or in an ice bath for 4-5 hours to obtain an intermediate diaryl sulfide compound; wherein the Lewis acid catalyst is ZnCl2, AlCl3, FeCl3 or SnCl4, and the first solvent is dichloromethane, dichloroethane, chloroform or glacial acetic acid, etc.;

[0044] Step 2: reacting a diaryl sulfide compound represented by formula II with p-chlorobenzophenone represented by formula III to synthesize an aryl sulfide benzophenone compound represented by formula IV; dissolving the intermediate II diaryl sulfide and compound III p-chlorobenzophenone in a second solvent, adding a base, and heating the reaction for 2-5 hours at a temperature of 50-120° C., preferably 80-100° C. After the reaction is completed, the organic solvent is distilled off, the mixture is cooled to room temperature, added to water, extracted with ethyl acetate, the organic phase is separated, washed with water, dried, concentrated, and recrystallized to obtain compound IV;

[0045] Alternatively, a diaryl sulfide compound represented by formula II is reacted with a p-chlorophenylaminoketone compound represented by formula V to synthesize an aryl sulfide α-aminoketone compound represented by formula VI; the intermediate II diaryl sulfide and the compound V p-chlorophenylaminoketone are dissolved in a third solvent, a base is added, and the temperature is raised to react for 2-5 hours at a reaction temperature of 50-120° C., preferably 80-100° C. After the reaction is completed, the organic solvent is distilled off, the mixture is cooled to room temperature, and the mixture is added to water, extracted with ethyl acetate, and the organic phase is separated, washed with water, dried, concentrated, and recrystallized to obtain compound VI;

[0046] Among them, the second solvent and the third solvent can be one or more of dichloromethane, dichloroethane, chloroform, acetone, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone, preferably N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone; the base is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride or potassium hydride, preferably sodium carbonate or sodium hydroxide; the molar ratio of intermediate II to compound III or V is 0.5:1 to 1:1, preferably 0.5:1 to 0.7:1.

[0047] The above-mentioned synthesis method is greener and easier to industrialize, and avoids the use of odorous thiophenol, thereby achieving green synthesis.

[0048] The following describes the embodiments of the present invention. Experimental methods without specific operating steps are performed according to the corresponding product specifications. Unless otherwise specified, the instruments, reagents, and consumables used in the embodiments can be purchased from commercial companies.

[0049] Example 1: Synthesis of diphenyl disulfide IIa (R1=R2=R3=R4=R5=H)

[0050]

[0051] To a 50 mL three-necked flask, add 5 mL of benzene and anhydrous aluminum chloride (2.70 g, 20 mmol, 1 eq). Stir thoroughly in an ice-water bath. Equipped with a thermometer, a spherical condenser, and a constant-pressure dropping funnel, weigh disulfur dichloride (2.67 g, 20 mmol, 1 eq) and transfer it to the dropping funnel with 5 mL of benzene. Slowly add disulfur dichloride dropwise. The system releases a large amount of heat and hydrogen chloride gas, and the solution gradually changes from orange-red to black with the addition of disulfur dichloride. After the addition of disulfur dichloride is complete, heat to 30°C and react for 5 h. After the reaction is complete, slowly add 20 mL of ice water dropwise to the reaction solution. This causes a vigorous exotherm, the release of a large amount of hydrogen chloride gas, and the precipitation of a white solid. Stir for 10 min, filter, and extract the filtrate with a small amount of EA. The lower aqueous phase is separated and the filtered solid is thoroughly dissolved in 20 mL of EA, and the aluminum salts are filtered out. The organic phases were combined, washed three times with 20 mL of water, dried, and spun down to obtain an orange-yellow liquid that solidified upon standing. Recrystallization from 15 mL of ethanol afforded needle-like crystals with a yield of 28.8% and a melting point of 64-70°C.

[0052] Example 2: Synthesis of di-s-triphenyl disulfide IIb (R1= R3= R5= CH3, R2= R4=H)

[0053]

[0054] In a 100 mL three-necked flask, mesitylene (10 g, 83.3 mmol, 1 eq), disulfur dichloride (5.625 g, 41.5 mmol, 0.5 eq) and 25 mL of glacial acetic acid were added, stirred to dissolve, and anhydrous zinc chloride (1.02 g, 7.5 mmol, 0.09 eq) was added. The reaction was allowed to proceed at room temperature for 4 h. After the reaction was completed, 40 mL of water was slowly added dropwise to the reaction solution. It was observed that the system generated a large amount of heat, a large amount of light yellow precipitate was precipitated, and hydrogen chloride gas was released. After stirring for 10 min, the mixture was filtered and the resulting precipitate was washed with water and methanol and dried in air. The crude yield was 94%. Recrystallization from petroleum ether gave light yellow flaky crystals with a melting point of 112-117 ° C. 1 H NMR (400 MHz, CDCl3) δ / ppm 6.86(s, 4H), 2.28(s, 6H), 2.23 (s, 12H); HR-MS(ESI, m / z): Calad. For C 18 H 22 S2 302.4940 (M + ), Found 302.1155(M + ).

[0055] Example 3: Synthesis of di(4-tert-butyl-2,3-dimethyl)phenyl disulfide IIc (R1= R5= CH3, R3= t-Bu, R2= R4=H)

[0056]

[0057] To a 100 mL three-necked flask, add 1-tert-butyl-3,5-dimethylbenzene (10 g, 61.7 mmol, 1 eq), disulfur dichloride (4.17 g, 30.9 mmol, 0.5 eq), and 35 mL of glacial acetic acid. Stir to dissolve. Add anhydrous zinc chloride (0.59 g, 4.32 mmol, 0.06 eq) and react at room temperature for 4 h. Monitor the reaction by TLC. After completion of the reaction, slowly add 40 mL of water dropwise to the reaction solution. The solution turns into a milky white emulsion and an orange oily insoluble material precipitates. Stir for 10 min and filter. Dissolve the upper orange oil in the filtrate with 10 mL of EA, and remove the lower emulsion. Dissolve the filtered solid in EA. Combine the organic phases, wash with water, dry, and spin-dry the solvent to obtain a yellow oil, which solidifies to a yellow solid upon standing. Recrystallize with isopropanol to obtain yellow needle-shaped crystals with a yield of 45% and a melting point of 116-120°C. 1 H NMR (400 MHz, CDCl3) δ / ppm 7.04(s, 4H), 2.23(s,12H), 1.30(s, 18H).

[0058] Example 4: Synthesis of Compound IVa (R1=R2=R3=R4=R5=H)

[0059]

[0060] Compound III (4.25 g, 19.63 mmol, 1 eq), NaOH (1.37 g, 34.35 mmol, 1.75 eq), and IIa (3.0 g, 19.63 mmol, 0.7 eq) were weighed into a 100 mL three-necked flask and dissolved in 15 mL of DMF. The mixture was heated to 100°C for 2 h, and the reaction progress was monitored by TLC. After the reaction was completed and the system cooled to room temperature, 20 mL of water was added, which quickly precipitated a large amount of white solid. The filtrate was filtered, extracted with 5 mL of EA, and the lower aqueous phase was removed. The filtered solid was dissolved in EA and combined with the organic phase of the filtrate, washed with water, dried, and spin-dried to obtain a white solid. Recrystallization from 20 mL of PE afforded white crystals in a 93% yield, melting point 64-66°C.

[0061] 1H NMR (400 MHz, CDCl3) δ / ppm 7.78-7.71(d, 2H), 7.71-7.64(d, 2H), 7.58-7.34(m, 8H), 7.26-7.19(d, 2H).

[0062] 13 C NMR (101 MHz, CDCl3) δ / ppm 195.8, 144.4, 137.7, 134.8, 133.9,132.4, 132.2, 130.8, 129.9, 128.3, 127.4.

[0063] HR-MS (ESI, m / z) Calad. For C 19 H 14 OSNa 313.3700(M + +Na), Found 313.0660(M + +Na).

[0064] Example 5: Synthesis of Compound IVb (R1= R3= R5= CH3, R2= R4=H)

[0065]

[0066] Compound III (2.24 g, 10.35 mmol, 1 eq), NaOH (0.993 g, 24.82 mmol, 2.4 eq), and compound IIb (2.5 g, 8.28 mmol, 0.8 eq) were weighed into a 100 mL three-necked flask and dissolved in 12 mL of DMF. The mixture was heated to 120°C and allowed to react for 2 h. Upon completion, 30 mL of water was added to the system, resulting in the precipitation of a large amount of white solid. The filtrate was filtered, extracted with 5 mL of EA, and the aqueous phase was separated. The filtered solid was dissolved in EA. The organic phases were combined and washed three times with 30 mL of water. The solid was dried and spin-dried to dryness to obtain a white solid. Recrystallization from polyethylene (PE) afforded white granular crystals in an 88% yield, with a melting point of 95-98°C.

[0067] 1 H NMR (400 MHz, CDCl3) δ / ppm 7.80-7.74(m, 2H), 7.71-7.63(m, 2H), 7.61-7.55(m, 1H), 7.51-7.44(m, 2H), 7.07(s, 2H), 7.02-6.95(d, 2H), 2.41(s,6H), 2.36(s, 3H).

[0068] 13 C NMR (101 MHz, CDCl3) δ / ppm 195.8, 145.3, 143.8, 140.0, 137.9,133.6, 132.2, 130.9, 128.4, 125.5, 124.5, 21.6, 21.2.

[0069] HR-MS (ESI, m / z) Calad. For C 22 H 20 OSNa 355.4510 (M + +Na), Found 355.1132M + +Na).

[0070] Example 6: Synthesis of Compound IVc (R1 = R5 = CH3, R3 = t-Bu, R2 = R4 = H)

[0071]

[0072] Compound III (2.10 g, 9.72 mmol, 1 eq), NaOH (0.933 g, 23.32 mmol, 2.4 eq), and compound IIc (3 g, 7.77 mmol, 0.8 eq) were weighed into a 100 mL three-necked flask and dissolved in 15 mL of DMF. The mixture was heated to 130°C for 2 h, and the reaction progress was monitored by TLC. After the reaction was complete and the system cooled, 30 mL of water was added to precipitate a large amount of white solid. The filtrate was filtered, extracted with 5 mL of EA, and the aqueous phase was separated. The filtered solid was dissolved in EA. The organic phases were combined and washed three times with 30 mL of water. Drying and spin drying yielded a white solid. Recrystallization from polyethylene afforded white needle-like crystals in a 75% yield, melting point 123-125°C.

[0073] 1 H NMR (400 MHz, CDCl3) δ / ppm 7.81-7.74(d, 2H), 7.72-7.65(d, 2H), 7.61-7.55(m, 1H), 7.53-7.44(m, 2H), 7.26(d, 2H), 7.05-6.96(d, 2H), 2.45(s,6H), 1.37(s,9H).

[0074] 13C NMR (101 MHz, CDCl3) δ / ppm 195.8, 153.1, 145.3, 143.3, 137.9,133.5, 132.1, 130.9, 129.8, 128.2, 125.9, 125.5, 124.5, 34.6, 31.3, 22.0.

[0075] HR-MS (ESI, m / z) Calad. For C 25 H 26 OSNa 397.5320 (M + +Na), Found 397.1599(M + +Na).

[0076] Example 7: Synthesis of Compound VIa (R1=R2=R3=R4=R5=H)

[0077]

[0078] Compound V (5.246 g, 19.63 mmol, 1 eq) was weighed into a 100 mL three-necked flask, and 15 mL of DMF was added and stirred to dissolve. NaOH (1.375 g, 34.35 mmol, 1.75 eq) and IIa (3.0 g, 13.74 mmol, 0.7 eq) were added to the reaction mixture, and the temperature was raised to 100°C for 2 h. The reaction was monitored by TLC. After the reaction was completed, the system was cooled to room temperature and 20 mL of water was added, resulting in the precipitation of a large amount of solid. The filtrate was filtered, extracted with 5 mL of EA, and the aqueous phase was separated. The filtered solid was thoroughly dissolved in EA. The organic phases were combined and washed with 30 mL of water until the aqueous phase showed no significant color. The solution was dried and the solvent was evaporated to dryness, yielding an orange-yellow viscous liquid, which solidified to a yellow-white solid upon standing. Recrystallization from polyethylene afforded yellow-white crystals in a 74% yield, with a melting point of 99-102°C.

[0079] 1 H NMR (400 MHz, CDCl3) δ / ppm δ / ppm 8.52-8.42(d, 2H), 7.62-7.49(m,2H), 7.48-7.38(m, 3H), 7.23-7.12(d,2H), 3.75-3.65(t, 4H), 2.62-2.53(t, 4H),1.32(s,6H).

[0080] 13C NMR (101 MHz, CDCl3) δ / ppm 202.3, 144.0, 140.0, 132.9, 132.2,131.0, 129.7, 128.8, 126.7, 68.4, 67.4, 47.0, 20.2.

[0081] HR-MS (ESI, m / z) Calcd. for C 20 H 24 NO2S 342.4770 (M + +H), Found 342.15243(M + +H).

[0082] Example 8: Synthesis of Compound VIb (R1= R3= R5= CH3, R2= R4=H)

[0083]

[0084] Compound V (2.60 g, 9.72 mmol, 1 eq), NaOH (0.933 g, 23.32 mmol, 2.4 eq), and IIb (2.35 g, 7.77 mmol, 0.8 eq) were weighed into a 100 mL three-necked flask and dissolved in 15 mL of DMF. The mixture was heated to 120°C for 2 h, and the reaction progress was monitored by TLC. Upon completion, the system was cooled to room temperature and 30 mL of water was added, which quickly precipitated a large amount of white solid. After thorough stirring, the mixture was filtered, and the filtrate was extracted with 5 mL of EA. The aqueous phase was separated and the filtered solid was dissolved in EA and combined with the organic phase of the filtrate. The solid was washed with 30 mL of water until the aqueous phase was colorless. The organic phase was dried and spun down to dryness, yielding an orange-red oily liquid, which solidified into an orange-yellow solid upon standing. Recrystallization from polyethylene afforded white needle-shaped crystals in a 68% yield. Melting point: 129-131°C.

[0085] 1 H NMR (400 MHz, CDCl3) δ / ppm 8.45-8.37(d, 2H), 7.11-7.05(s, 2H), 6.96-6.86(d, 2H), 3.73-3.64(t, 4H), 2.61-2.53(t, 4H), 2.40(s, 6H), 2.37(s,3H), 1.30(s, 6H).

[0086] 13C NMR (101 MHz, CDCl3) δ / ppm 202.3, 144.8, 143.8, 139.9, 131.8,130.9, 129.5, 125.6, 123.9, 68.4, 67.4, 47.0.

[0087] HR-MS (ESI, m / z) Calad. For C 23 H 30 NO2S 384.5580((M + +H), Found 384.19953(M + +H).

[0088] Example 9: Synthesis of Compound VIc (R1 = R5 = CH3, R3 = t-Bu, R2 = R4 = H)

[0089]

[0090] Compound V (0.861 g, 3.24 mmol, 1 eq), NaOH (0.311 g, 7.7 mmol, 2.4 eq), and IIc (1.0 g, 2.59 mmol, 0.8 eq) were weighed into a 50 mL three-necked flask and dissolved in 5 mL of DMF. The mixture was heated to 130°C for 2 h, and the reaction progress was monitored by TLC. After the reaction was complete and the system cooled to room temperature, 20 mL of water was added, and a large amount of solid precipitated rapidly. The filtrate was filtered, extracted with a small amount of EA, and the aqueous phase was separated. The filtered solid was dissolved in EA and filtered. The combined organic phases were washed with 20 mL of water until the aqueous phase was essentially colorless. The product was dried and spun down to dryness, yielding an orange-yellow oily liquid that gradually solidified after standing for several hours. Recrystallization from polyethylene afforded a yellowish-white solid in a 58% yield, melting point 101-104°C.

[0091] 1 H NMR (400 MHz, CDCl3) δ / ppm 8.49-8.36(d, 2H), 7.26(s, 2H), 6.96-6.90(d, 2H), 3.76-3.64(t, 4H), 2.64-2.53(t, 4H), 2.45(s, 6H), 1.38(s, 9H), 1.31(s, 6H).

[0092] 13C NMR (101 MHz, CDCl3) δ / ppm 202.3, 152.9, 144.8, 143.4, 131.8, 131.0, 125.8, 124.0, 68.4, 67.4, 47.0, 34.6, 31.3, 22.1, 20.3.

[0093] HR-MS (ESI, m / z) Calad. For C 26 H 36 NO2S 426.6390((M + +H), Found 426.24640((M + +H).

[0094] Example 10: Determination of photocuring activity

[0095] The compounds prepared in Examples 4-9 were used as photoinitiators to test their photocuring activity; BP and 907 were used as comparative examples. The photoinitiator, resin, and co-initiator to be tested were weighed in varying proportions, placed in 5 mL brown glass bottles, and ultrasonically mixed thoroughly. The mixed coating was applied to a substrate (glass slide) using a 10 μm thick film preparation apparatus. The coated glass slide (coated part) was transported to the irradiation platform via a conveyor belt. The entire chamber was exposed to UV light as the coated part passed through it. The amount of UV radiation received by the coating could be controlled by adjusting the number of lamps (i.e., power) and the conveyor belt speed. According to the national standard GB / T1728-1979 surface drying time determination method, the cured coating surface was gently wiped with a paper towel. No scratches indicated that the photoinitiator had successfully initiated the resin to form a film. The energy required to cure the liquid film was recorded using a UV energy meter; lower energy levels indicate better photocuring efficiency.

[0096] Table 1 Photocuring activity test

[0097]

[0098] The results are shown in Table 1. The compounds prepared in Examples 4-9 can be used as photoinitiators and can cure resins after UV irradiation. Compounds IVa and VIc have similar curing effects to BP, while compounds VIa and VIb have better curing effects.

[0099] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A diaryl sulfide photoinitiator, characterized in that: The structure is shown in Formula IV or Formula VI; ； ； Among them, R1-R5 are H or C1-C5 alkyl, alkoxy, alkylthio, dialkylamino, and R1-R5 can be the same, partially the same, or different.

2. The diaryl sulfide photoinitiator according to claim 1, characterized in that: The structure is shown in any one of Formulas IVa, IVb, IVc, VIa, VIb and VIc, ， ， ， ， ， 。 3. A method for preparing the diaryl sulfide photoinitiator according to claim 1 or 2, characterized in that: The substituted benzene compound is reacted with sulfur chloride to prepare an intermediate diaryl sulfide compound; the intermediate diaryl sulfide compound is then reacted with p-chlorobenzophenone or p-chlorophenylaminoketone to prepare a diaryl sulfide photoinitiator of formula IV or formula VI.

4. The method for preparing a diaryl sulfide photoinitiator according to claim 3, wherein: The specific preparation method is as follows: Step 1: reacting a substituted benzene compound represented by Formula I with S2Cl2 to synthesize a diaryl sulfide compound represented by Formula II; ， ； Wherein, R1-R5 are H or C1-C5 alkyl, alkoxy, alkylthio, or dialkylamino, and R1-R5 may be the same, partially the same, or different; Step 2: reacting the diaryl sulfide compound represented by formula II with p-chlorobenzophenone to synthesize the aryl sulfide benzophenone compound represented by formula IV; Alternatively, the diaryl sulfide compound represented by formula II is reacted with p-chlorophenyl aminoketone to synthesize the aryl sulfide α-aminoketone compound represented by formula VI.

5. The method for preparing a diaryl sulfide photoinitiator according to claim 4, wherein: In step 1, a substituted benzene compound and S2Cl2 are dissolved in a first solvent, or S2Cl2 is dissolved in a substituted benzene solvent, and a Lewis acid is used as a catalyst to react at room temperature or low temperature to obtain an intermediate diaryl sulfide compound.

6. The method for preparing a diaryl sulfide photoinitiator according to claim 5, wherein: The Lewis acid catalyst is ZnCl2, AlCl3, FeCl3 or SnCl4; The first solvent is dichloromethane, dichloroethane, chloroform or glacial acetic acid.

7. The method for preparing a diaryl sulfide photoinitiator according to claim 4, wherein: In step 2, the intermediate diaryl sulfide compound represented by formula II and p-chlorobenzophenone are dissolved in a second solvent, a base is added, and the reaction is carried out at 50-120° C. After removing the organic solvent, the product is added to water, extracted with ethyl acetate, and recrystallized to obtain the aryl sulfide benzophenone compound represented by formula IV; The second solvent is one or more of dichloromethane, dichloroethane, chloroform, acetone, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; The base is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride or potassium hydride; The molar ratio of the compound of formula II to p-chlorobenzophenone is 0.5:1 to 1:

1.

8. The method for preparing a diaryl sulfide photoinitiator according to claim 4, wherein: In step 2, the intermediate diaryl sulfide compound represented by formula II and p-chlorophenyl aminoketone are dissolved in a third solvent, a base is added, and the reaction is carried out at 50-120° C. After removing the organic solvent, the product is added to water, extracted with ethyl acetate, and recrystallized to obtain the aryl sulfide α-aminoketone compound represented by formula VI; The third solvent is one or more of dichloromethane, dichloroethane, chloroform, acetone, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; The base is sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, sodium hydride or potassium hydride; The molar ratio of the compound of formula II to p-chlorobenzophenone is 0.5:1 to 1:

1.

9. Use of the diaryl sulfide photoinitiator according to claim 1 or 2 in photocuring.

10. The use according to claim 9, characterized in that: The diaryl sulfide photoinitiator is mixed with the resin and the co-initiator, and curing is achieved after ultraviolet light irradiation.

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