Cationic photoinitiator intermediate and preparation method thereof, and water-soluble cationic photoinitiator and preparation method thereof

Abstract

The invention discloses a cationic photoinitiator intermediate and a preparation method thereof, and the molecular structure of the cationic photoinitiator intermediate is shown as a formula 3. The invention also discloses a cationic photoinitiator prepared from the cationic photoinitiator intermediate, and the molecular structure of the cationic photoinitiator is shown as a formula Y, the molecular structure of the cationic photoinitiator is specifically designed, the solubility, the photo-initiation efficiency and the safety of the cationic photoinitiator in a water-based system are remarkably improved, the prepared cationic photoinitiator can stably exist in environment-friendly solvents such as water and ethyl alcohol, the problem that the cationic photoinitiator is sensitive to water is solved, and the cationic photoinitiator can be applied to water-based photoinitiators. According to the cationic photoinitiator, the polymerization inhibition effect is avoided, good photo-initiation efficiency is also shown, meanwhile, the molecular structure of the cationic photoinitiator can be copolymerized with a monomer in photo-initiation polymerization reaction, covalent binding to a polymer main chain after curing is achieved, and therefore the migration problem of the photoinitiator is effectively avoided, and the invention further discloses a preparation method of the cationic photoinitiator.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoinitiators, and in particular relates to a cationic photoinitiator intermediate and a preparation method thereof. The present invention also relates to a water-soluble cationic photoinitiator and a preparation method thereof. Background Art

[0002] Photocuring technology has been widely used in the fields of coatings, inks, adhesives, electronic materials and 3D printing due to its advantages of rapidness, energy saving and environmental protection. Traditional photocuring systems are usually based on non-environmentally friendly organic solvents, and activate the cross-linking reaction between monomers and oligomers by introducing photoinitiators.

[0003] The main photoinitiators used in the market can be divided into two categories: free radical type and cationic type. Typical cationic photoinitiators are sulfonium salt initiators, which can generate proton acids through ultraviolet light irradiation to initiate the polymerization of epoxy, vinyl ether and other systems. Although cationic photoinitiators show excellent initiation ability in an environment with oxygen, they still have the following shortcomings:

[0004] 1. Cationic photoinitiators have poor solubility in many environmentally friendly solvents, especially in low-toxic environmentally friendly solvents such as alcohols, which are difficult to dissolve completely, resulting in low photocuring efficiency and even inability to achieve uniform dispersion, affecting the curing efficiency and the performance of the final product. This makes it difficult for traditional photoinitiators to meet increasingly stringent environmental regulations.

[0005] 2. Sensitivity to water: Traditional sulfonium salt cationic photoinitiators are very sensitive to water because the nucleophilicity of water molecules will destroy the cationic chain reaction in the initiation system, which can easily lead to the inhibition of the photopolymerization process, the so-called "inhibition" effect. Therefore, the use of such initiators in water-based photocuring systems usually requires an extremely strict water-free environment, which increases the complexity and cost of the photocuring process.

[0006] 3. Migration issues: Traditional photoinitiators only act as initiators during the polymerization process and do not participate in the final polymerization network. Therefore, they are in a free state in the solidified material, causing the photoinitiator molecules to easily migrate to the surface of the material, resulting in a decrease in the physical and chemical properties of the solidified material. In addition, the migrated photoinitiators may also pollute the environment or cause harm to human health, especially in sensitive areas such as food packaging and medical devices, where there are significant safety risks.

[0007] 4. VOC emission problem: Traditional organic solvent photocuring systems usually require a large amount of non-environmentally friendly organic solvents. These solvents will evaporate during use and drying, generating volatile organic compound (VOC) emissions, causing air pollution and increasing the environmental burden. Therefore, the development of photoinitiators that can be dissolved in environmentally friendly solvents to reduce VOC emissions has become an important research direction in the field of photocuring. Summary of the invention

[0008] In view of the problems in the related art, the present invention proposes a cationic photoinitiator intermediate and a preparation method thereof. The present invention also discloses a cationic photoinitiator and a preparation method thereof through the cationic photoinitiator intermediate. By improving the molecular structure of an aryl formylmethyl sulfonium salt and introducing an imidazole group as an ionic liquid functional group, the solubility of the photoinitiator of the present invention in an environmentally friendly solvent is significantly improved, so that it can be evenly dispersed in the solution, thereby ensuring efficient initiation of photocuring; at the same time, by introducing a hydrocarbon group containing a double bond into the photoinitiator structure, the photoinitiator not only initiates polymerization during the polymerization process of the component system, but also can participate in the cross-linking reaction itself, thereby effectively reducing the migration risk after curing, and improving the stability and safety of the final product, so as to overcome the above-mentioned technical problems existing in the existing related art.

[0009] The technical solution of the present invention is achieved in this way:

[0010] A cationic photoinitiator intermediate, the molecular structure of which is shown in Formula 3:

[0011]

[0012] Wherein, R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups, that is, R1 and R2 can be the same or different.

[0013] Preferably, the alkyl group is C n H m , wherein n and m are independently natural numbers less than 30; the molecular structure of the oligoether group is Here, m is a natural number less than 30.

[0014] Preferably, the cationic photoinitiator intermediate is one of the following formulas 1-3 to 8-3:

[0015]

[0016] The method for preparing the above cationic photoinitiator intermediate comprises at least the following steps:

[0017] 1) Compound B-1 is dissolved in an organic solvent, cooled to 0-5°C, and phosgene and aluminum chloride as shown in formula B-2 are slowly added as catalysts, the molar ratio of compound B-1 to phosgene B-2 is 1:1-1.5, stirred for 3-5 hours, and then the reactants are poured into ice water for neutralization, and then liquid-liquid extraction, drying and rotary evaporation are performed to obtain intermediate B-3;

[0018]

[0019] 2) Dissolve the intermediate B-3 in an organic solvent, add N-bromosuccinimide and benzoyl peroxide, the molar ratio of the intermediate B-3 to N-bromosuccinimide is 1:1-1.5, the system temperature is ≤0°C, stir for 1-3h, then warm to room temperature, continue stirring for 3-5h, neutralize with sodium carbonate after the reaction, and perform liquid-liquid extraction to obtain the intermediate B-4, whose structure is shown in formula B-4:

[0020]

[0021] 3) The intermediate B-4 is dissolved in an organic solvent, and dialkyl sulfide R1SR2 and potassium hexafluoroantimonate are added, the molar ratio of the intermediate B-4, dialkyl sulfide R1SR2 and potassium hexafluoroantimonate is 1:1-1.5:1-1.5, and the reaction is stirred at room temperature for 7-9 hours, and then poured into ice water to precipitate a solid, and the solid is filtered, washed and dried to obtain an intermediate 2, whose molecular structure is shown in 2:

[0022]

[0023] Wherein, R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups, that is, R1 and R2 can be the same or different.

[0024] Preferably, the alkyl group is C n H m , wherein n and m are independently natural numbers less than 30; the molecular structure of the oligoether group is Here, m is a natural number less than 30.

[0025] 4) The intermediate 2 is dissolved in an organic solvent, cooled to ≤0°C, and boron tribromide is slowly added dropwise, the molar ratio of the intermediate 2 to boron tribromide is 1:1-1.5, stirred for 0.5-1.5h, then warmed to room temperature, and continued to stir for 5-7h; after the reaction, the mixture is poured into ice water for neutralization, and a cationic photoinitiator intermediate 3 is obtained by liquid-liquid extraction, drying and recrystallization, and its molecular structure is shown in 3:

[0026]

[0027] Wherein, R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups, that is, R1 and R2 can be the same or different.

[0028] Preferably, the alkyl group is C n H m , wherein n and m are independently natural numbers less than 30; the molecular structure of the oligoether group is Here, m is a natural number less than 30.

[0029] A water-soluble cationic photoinitiator, whose molecular structure is shown in Formula Y:

[0030]

[0031] Among them, R is * is the link position, n is a natural number greater than 1 and less than 30;

[0032] R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups, that is, R1 and R2 may be the same or different.

[0033] Preferably, the alkyl group is C n H m , where n and m are both independently natural numbers less than 30.

[0034] Preferably, the molecular structure of the oligoether group is Here, m is a natural number less than 30.

[0035] The cationic photoinitiator of the present invention is a water-soluble cationic photoinitiator.

[0036] Preferably, the molecular structure of the water-soluble cationic photoinitiator is one of the following formulas Y-1 to Y-16:

[0037]

[0038] The preparation method of the water-soluble cationic photoinitiator comprises at least the following steps:

[0039] 1) preparing the above-mentioned cationic photoinitiator intermediate 3;

[0040] 2) Dissolve the cationic photoinitiator intermediate 3 in an organic solvent, then add an imidazole derivative, the molar ratio of the cationic photoinitiator intermediate 3 to the imidazole derivative is 1:1-1.5, heat the system temperature to 75-85°C, stir the reaction for 11-13 hours, and after cooling, remove the organic solvent by rotary evaporation, wash and recrystallize to obtain a water-soluble cationic photoinitiator Y.

[0041] Preferably, in step 2), the molecular structure of the imidazole derivative is as shown in 4:

[0042]

[0043] Beneficial effects of the present invention:

[0044] The aryl formylmethyl sulfonium salt derivative is combined with a specific imidazole group through a multi-step reaction to form a cationic photoinitiator with ionic liquid characteristics, thereby ensuring that the cationic photoinitiator of the present invention can be efficiently initiated, and by introducing the imidazole group into the molecular structure, the cationic photoinitiator of the present invention can be stably present in environmentally friendly solvents such as water and ethanol, thereby solving the problem that the cationic photoinitiator is sensitive to water, avoiding the occurrence of the inhibition effect, simplifying the operating conditions, and reducing the cost of the curing system.

[0045] By reasonable molecular design and the introduction of hydrocarbon groups containing double bonds, the photoinitiator of the present invention can participate in the polymerization process while initiating the polymerization reaction to form a covalently bonded polymer network structure, thereby effectively reducing the migration of the initiator and meeting application scenarios with strict requirements on product safety.

[0046] The present invention realizes the comprehensive optimization of the solubility, initiation efficiency and mobility of the cationic photoinitiator through a specific structural design, which can effectively improve the curing rate and product performance. It can be applied to cationic polymerization photocuring systems such as vinyl ether, and is particularly suitable for fields such as food packaging and medical coatings, and meets the requirements of low mobility and high initiation efficiency. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Example 1

[0049] The synthetic route of this embodiment is shown in the figure below:

[0050]

[0051] 1) Preparation of intermediate B-3

[0052] 1.1) In a dry three-necked flask, weigh 196 g of compound B-1 (1 mol), add an appropriate amount of anhydrous toluene as solvent, stir under nitrogen protection, slowly add 92.5 g of compound B-2 (1 mol), and add an appropriate amount of aluminum chloride as a catalyst.

[0053] 1.2) React at room temperature for 4 h, and keep stirring during the reaction.

[0054] 1.3) After the reaction is completed, the reaction mixture is poured into ice water for neutralization to generate a solid; the solid is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral; the obtained crude product is recrystallized from ethanol to finally obtain 183.34 g of intermediate B-3 with a yield of 89%. The H NMR spectrum data is:

[0055] 1 H NMR (500MHz, Chloroform) δ8.43–7.83 (m, 3H), 7.11 (dd, J = 7.5, 1.4Hz, 1H), 3.81 (s, 3H), 2.50 (s, 3H).

[0056] 2) Preparation of intermediate B-4

[0057] 2.1) In a dry three-necked flask, weigh 154.5 g of compound B-3 (0.75 mol), add an appropriate amount of anhydrous tetrahydrofuran (THF) as a solvent, stir at room temperature, slowly add 133.5 g of N-bromosuccinimide (NBS, 0.75 mol), and at the same time add an appropriate amount of benzoyl peroxide as a free radical initiator.

[0058] 2.2) The reaction system was heated to 70°C and maintained for 6 h to ensure that the bromination reaction was complete.

[0059] 2.3) After the reaction is completed, the reaction mixture is cooled to room temperature, the by-product of bromosuccinimide is filtered off, and the filtrate is collected; the solvent is removed by rotary evaporation, and the obtained crude product is recrystallized from ethanol to finally obtain 181.7 g of intermediate B-4 with a yield of 85%. The H NMR spectrum data is:

[0060] 1 H NMR (500MHz, Chloroform) δ8.32–8.14(m,2H),8.03(d,J=3.1Hz,1H),7.11(dd,J=15.0,2.9Hz,1H),4.83(s,2H),3.81(s,3H).

[0061] Example 2

[0062] The synthetic route of this embodiment is shown in the figure below:

[0063]

[0064] 3) Preparation of intermediate 1-2

[0065] 3.1) In a dry three-necked flask, weigh 142.5 g of compound B-4 (0.5 mol) obtained in Example 1, add 31 g of dimethyl sulfide (1-1, 0.5 mol), and add 137 g of potassium hexafluoroantimonate (KSbF6, 0.5 mol) as a reaction reagent, add an appropriate amount of butanone into the flask as a solvent, and stir under nitrogen protection.

[0066] 3.2) The reaction system was heated to reflux temperature and maintained at reflux for 8 h to promote complete reaction.

[0067] 3.3) After the reaction was completed, the reaction mixture was cooled to room temperature, filtered to remove insoluble matter, and the filtrate was collected. After the solvent was removed by rotary evaporation, the obtained crude product was recrystallized from ethanol to finally obtain 203.9 g of intermediate 1-2 with a yield of 81% and a molecular weight of 501.95 determined by MS.

[0068] 4) Preparation of cationic photoinitiator intermediates 1-3

[0069] 4.1) In a dry three-necked flask, weigh 125.25 g of compound 1-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as solvent, stir under nitrogen protection, slowly add 62.6 g of boron tribromide (BBr3, 0.25 mol), gradually heat the reaction system to room temperature, and keep the reaction for 6 hours to ensure complete removal of the methoxy group.

[0070] 4.2) After the reaction is completed, ice water is slowly added to the system to terminate the reaction and neutralize the generated by-product HBr; the reaction mixture is subjected to liquid-liquid extraction and the organic phase is collected; after drying, the solvent is removed by rotary evaporation, and the obtained crude product is recrystallized with ethanol to finally obtain 106.09 g of cationic photoinitiator intermediate 1-3 with a yield of 87% and a molecular weight of 487.93 determined by MS.

[0071] Example 3

[0072] The synthetic route of this embodiment is shown in the figure below:

[0073]

[0074] 3) Preparation of intermediate 2-2

[0075] 3.1) In a dry three-necked flask, weigh 142 g of the intermediate B-4 (0.5 mol) obtained in Example 1, add an appropriate amount of anhydrous butanone as a solvent, stir under nitrogen protection, add 45 g of diethyl sulfide (0.5 mol), and add 137 g of potassium hexafluoroantimonate (0.5 mol).

[0076] 3.2) The mixture was stirred at 80°C for 6 h and then cooled to room temperature.

[0077] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 220.45 g of intermediate 2-2 with a yield of 83%. The molecular weight determined by MS was 529.98.

[0078] 4) Preparation of cationic photoinitiator intermediate 2-3

[0079] 4.1) In a dry three-necked flask, weigh 132.5 g of intermediate 2-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as solvent, slowly add 62.5 g of boron tribromide (0.25 mol) dropwise at 0°C, and continue stirring and reacting for 3 h after the addition is complete.

[0080] 4.2) After the reaction, the mixture was poured into ice water for liquid-liquid extraction. The separated organic phase was dried and evaporated to remove the solvent to finally obtain a crude product. The crude product was recrystallized from ethanol to obtain 104.55 g of cationic photoinitiator intermediate 2-3 with a yield of 81% and a molecular weight of 515.96 determined by MS.

[0081] Example 4

[0082] The synthetic route of this embodiment is shown in the figure below:

[0083]

[0084] 3) Preparation of intermediate 3-2

[0085] 3.1) In a dry three-necked flask, weigh 142 g of the intermediate B-4 (0.5 mol) obtained in Example 1, add an appropriate amount of anhydrous butanone as a solvent, and stir under nitrogen protection. Add 59 g of dipropyl sulfide (0.5 mol) and 137 g of potassium hexafluoroantimonate (0.5 mol).

[0086] 3.2) The mixture was stirred at 80°C for 6 h and then cooled to room temperature.

[0087] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 246.24 g of intermediate 3-2 with a yield of 88%. The molecular weight determined by MS was 559.01.

[0088] 4) Preparation of cationic photoinitiator intermediate 3-3

[0089] 4.1) In a dry three-necked flask, weigh 139.5 g of intermediate 3-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as solvent, slowly add 62.5 g of boron tribromide (0.25 mol) dropwise at 0°C, and continue stirring and reacting for 3 h after the addition is complete.

[0090] 4.2) After the reaction, the mixture was poured into ice water for liquid-liquid extraction. The separated organic phase was dried and evaporated to remove the solvent to finally obtain a crude product. The crude product was recrystallized from ethanol to obtain 115.9 g of cationic photoinitiator intermediate 3-3 with a yield of 85%. The molecular weight determined by MS was 543.99.

[0091] Example 5

[0092] The synthetic route of this embodiment is shown in the figure below:

[0093]

[0094] 3) Preparation of intermediate 4-2

[0095] 3.1) In a dry three-necked flask, weigh 142 g of intermediate B-4 (0.5 mol), add an appropriate amount of anhydrous butanone as a solvent, stir under nitrogen protection, add 59 g of diisopropyl sulfide (4-1, 0.5 mol), and add 137 g of potassium hexafluoroantimonate (0.5 mol).

[0096] 3.2) The mixture was stirred at 80°C for 6 h and then cooled to room temperature.

[0097] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 232.14 g of intermediate 4-2 with a yield of 83%. The molecular weight determined by MS was 558.01.

[0098] 4) Preparation of cationic photoinitiator intermediate 4-3

[0099] 4.1) In a dry three-necked flask, weigh 139.5 g of intermediate 4-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as solvent, slowly add 62.5 g of boron tribromide (0.25 mol) dropwise at 0°C, and continue stirring and reacting for 3 h after the addition is complete.

[0100] 4.2) After the reaction, the mixture was poured into ice water for liquid-liquid extraction, and the separated organic phase was dried and evaporated to remove the solvent, finally obtaining a crude product. The crude product was recrystallized from ethanol to obtain 118.3 g of cationic photoinitiator intermediate 4-3, with a yield of 87% and a molecular weight of 543.99 determined by MS.

[0101] Example 6

[0102] The synthetic route of this embodiment is shown in the figure below:

[0103]

[0104] 3) Preparation of intermediate 5-2

[0105] 3.1) In a dry three-necked flask, weigh 142g of intermediate B-4 (0.5mol), add an appropriate amount of anhydrous butanone as solvent, stir under nitrogen protection, add 38g of ethyl methyl sulfide (5-1, 0.5mol), and add 137g of potassium hexafluoroantimonate (0.5mol).

[0106] 3.2) The mixture was stirred at 80°C for 6 h and then cooled to room temperature.

[0107] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 209.1 g of intermediate 5-2 with a yield of 81%. The molecular weight determined by MS was 515.96.

[0108] 4) Preparation of cationic photoinitiator intermediate 5-3

[0109] 4.1) In a dry three-necked flask, weigh 129 g of intermediate 5-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as solvent, slowly add 62.5 g of boron tribromide (0.25 mol) dropwise at 0°C, and continue stirring and reacting for 3 h after the addition is complete.

[0110] 4.2) After the reaction, the mixture was poured into ice water for liquid-liquid extraction, and the separated organic phase was dried and evaporated to remove the solvent, finally obtaining a crude product. The crude product was recrystallized from ethanol to obtain 104.2 g of cationic photoinitiator intermediate 5-3, with a yield of 83% and a molecular weight of 501.95 determined by MS.

[0111] Example 7

[0112] The synthetic route of this embodiment is shown in the figure below:

[0113]

[0114] 3) Preparation of intermediate 6-2

[0115] 3.1) In a dry three-necked flask, weigh 142g of intermediate B-4 (0.5mol), add an appropriate amount of anhydrous butanone as solvent, and stir under nitrogen protection. Add 45g of methyl propyl sulfide (6-1, 0.5mol) and 137g of potassium hexafluoroantimonate (0.5mol).

[0116] 3.2) The mixture was stirred at 80°C for 6 h and then cooled to room temperature.

[0117] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 241.2 g of intermediate 6-2 with a yield of 91%. The molecular weight determined by MS was 529.98.

[0118] 4) Preparation of cationic photoinitiator intermediate 6-3

[0119] 4.1) In a dry three-necked flask, weigh 129 g of intermediate 6-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as solvent, slowly add 62.5 g of boron tribromide (0.25 mol) dropwise at 0°C, and continue stirring and reacting for 3 h after the addition is complete.

[0120] 4.2) After the reaction, the mixture was poured into ice water for liquid-liquid extraction, and the separated organic phase was dried and evaporated to remove the solvent, finally obtaining a crude product. The crude product was recrystallized from ethanol to obtain 110.7 g of cationic photoinitiator intermediate 6-3, with a yield of 86% and a molecular weight of 515.96 determined by MS.

[0121] Example 8

[0122] The synthetic route of this embodiment is shown in the figure below:

[0123]

[0124] 3) Preparation of intermediate 7-2

[0125] 3.1) In a dry three-necked flask, weigh 142 g of intermediate B-4 (0.5 mol), add an appropriate amount of anhydrous butanone as a solvent, stir under nitrogen protection, add 101 g of dihexyl sulfide (7-1, 0.5 mol), and then add 137 g of potassium hexafluoroantimonate (0.5 mol).

[0126] 3.2) The mixture was stirred at 85°C for 6 hours and cooled to room temperature after the reaction was completed.

[0127] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 285.7 g of intermediate 7-2 with a yield of 89% and a molecular weight of 642.10 determined by MS.

[0128] 4) Preparation of cationic photoinitiator intermediate 7-3

[0129] 4.1) In a dry three-necked flask, weigh 157 g of intermediate 7-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as a solvent, cool the reaction system to 0°C, slowly drop 62.5 g of boron tribromide (0.25 mol), and continue stirring the reaction for 4 h after the addition is complete.

[0130] 4.2) After the reaction is completed, the reaction mixture is poured into ice water for neutralization, liquid-liquid extraction is performed, the organic phase is collected, the solvent is removed by rotary evaporation after drying, and finally recrystallization is performed by ethanol to obtain 136.9 g of cationic photoinitiator intermediate 7-3 with a yield of 87% and a molecular weight of 628.09 determined by MS.

[0131] Example 9

[0132] The synthetic route of this embodiment is shown in the figure below:

[0133]

[0134] 3) Preparation of intermediate 8-2

[0135] 3.1) In a dry three-necked flask, weigh 142g of intermediate B-4 (0.5mol), add an appropriate amount of anhydrous butanone as a solvent, stir under nitrogen protection, add 129g of dioctyl sulfide (8-1, 0.5mol), and then add 137g of potassium hexafluoroantimonate (0.5mol).

[0136] 3.2) The mixture was stirred at 85°C for 6 hours and cooled to room temperature after the reaction was completed.

[0137] 3.3) The reaction mixture was subjected to rotary evaporation to remove the solvent, and the obtained solid was washed with deionized water and recrystallized to obtain 293.2 g of intermediate 8-2 with a yield of 84%. The molecular weight determined by MS was 698.16.

[0138] 4) Preparation of cationic photoinitiator intermediate 8-3

[0139] 4.1) In a dry three-necked flask, weigh 174 g of intermediate 8-2 (0.25 mol), add an appropriate amount of anhydrous dichloromethane as a solvent, cool the reaction system to 0°C, slowly drop 62.5 g of boron tribromide (0.25 mol), and continue stirring the reaction for 4 h after the addition is complete.

[0140] 4.1) After the reaction is completed, the reaction mixture is poured into ice water for neutralization, liquid-liquid extraction is performed, the organic phase is collected, the solvent is removed by rotary evaporation after drying, and finally recrystallization is performed by ethanol to obtain 138.8 g of cationic photoinitiator intermediate 8-3 with a yield of 81% and a molecular weight of 684.15 determined by MS.

[0141] Example 10

[0142] The synthetic route of this embodiment is shown in the figure below:

[0143]

[0144] 5) Preparation of water-soluble cationic photoinitiator

[0145] 5.1) In a dry three-necked flask, weigh 48.7 g of intermediate 1-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as a solvent, stir under nitrogen protection, then add 38.1 g of compound 1-4 (0.1 mol), and continue to stir the reaction at room temperature for 8 h to ensure sufficient reaction.

[0146] 5.2) After the reaction is completed, the solvent is removed by rotary evaporation, the residue is dissolved with an appropriate amount of deionized water, the aqueous solution is decolorized with activated carbon and filtered to obtain a clear solution; the solution is then concentrated and freeze-dried to obtain cationic photoinitiator Y-1, the final yield is 67.81 g, the yield is 81%, and the H NMR spectrum data is:

[0147] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),8.34–8.12(m,2H),8.03(d,J=2.9Hz,1H),7.11(dd,J=1 5.0,3.1Hz,1H),6.07(ddt,J=33.3,20.0,12.3Hz,1H),5.45(ddt,J=33.5,4.0,1.9Hz,1H),5.23 (ddt,J=20.0,4.2,2.0Hz,1H),5.10(dt,J=12.5,1.9Hz,2H),4.51(d,J=7.5Hz,1H),4.42–4.21( m, 4H), 4.02 (td, J = 14.3, 1.0Hz, 2H), 3.77 (t, J = 7.0Hz, 2H), 3.64 (d, J = 7.5Hz, 1H), 3.52 (s, 4H).

[0148] Embodiment 11

[0149] The synthetic route of this embodiment is shown in the figure below:

[0150]

[0151] 5) Preparation of water-soluble cationic photoinitiator

[0152] 5.1) In a dry three-necked flask, weigh 51.6 g of intermediate 2-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as a solvent, stir under nitrogen protection, add 38.1 g of compound 2-4 (0.1 mol), and stir the mixture at room temperature for 8 h to ensure complete reaction.

[0153] 5.2) After the reaction, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-2. The final yield was 76.5 g, the yield was 85%, and the H NMR spectrum data was:

[0154] 1 H NMR(500MHz,Chloroform)δ8.91(s,1H),8.35–8.12(m,2H),8.02(d,J=2.9Hz,1H),7.10(d d,J=14.9,3.0Hz,1H),6.07(ddt,J=33.3,19.8,12.3Hz,1H),5.44(ddt,J=33.5,4.0,1.9Hz ,1H),5.23(ddt,J=20.0,4.1,2.0Hz,1H),5.10(dt,J=12.5,1.9Hz,2H),4.92–4.71(m,2H), 4.33(dt,J=29.3,11.1Hz,4H), 4.01(t,J=8.0Hz,2H), 3.77(t,J=14.6Hz,2H), 3.52(s,4H).

[0155] Example 12

[0156] The synthetic route of this embodiment is shown in the figure below:

[0157]

[0158] 5) Preparation of water-soluble cationic photoinitiator

[0159] 5.1) In a dry three-necked flask, weigh 54.3 g of intermediate 3-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as a solvent, stir under nitrogen protection, add 38.1 g of compound 3-4 (0.1 mol), and stir the mixture at room temperature for 8 h to ensure complete reaction.

[0160] 5.2) After the reaction, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-3. The final yield was 80.3 g, the yield was 87%, and the H NMR spectrum data was:

[0161] 1H NMR(500MHz,Chloroform)δ8.91(s,1H),8.31–8.10(m,2H),8.02(d,J=3.1Hz,1H),7.1 0(dd,J=15.0,3.1Hz,1H),6.07(ddt,J=33.6,20.0,12.4Hz,1H),5.33(dddt,J=102.6, 20.0,4.2,2.0Hz,2H),5.10(dt,J=12.4,1.8Hz,2H),4.85(dd,J=7.5,0.6Hz,1H),4.51 –4.23(m,5H),4.02(t,J=8.4Hz,2H),3.77(t,J=6.6Hz,2H),3.52(s,4H),0.94(s,6H).

[0162] Example 13

[0163] The synthetic route of this embodiment is shown in the figure below:

[0164]

[0165] 5) Preparation of water-soluble cationic photoinitiator

[0166] 5.1) In a dry three-necked flask, weigh 54.3 g of intermediate 4-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as a solvent, stir under nitrogen protection, add 38.1 g of compound 4-4 (0.1 mol), and stir the mixture at room temperature for 8 h to ensure complete reaction.

[0167] 5.2) After the reaction, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-4. The final yield was 69.0 g, the yield was 81%, and the H NMR spectrum data was:

[0168] 1H NMR(500MHz,Chloroform)δ8.92(s,1H),8.36–8.09(m,2H),8.03(d,J=2.9Hz,1H),7.11(dd,J =15.0,3.1Hz,1H),6.07(ddt,J=33.3,19.8,12.3Hz,1H),5.45(ddt,J=33.5,4.0,1.9Hz,1H), 5.23(ddt,J=20.0,4.2,2.0Hz,1H),5.10(ddt,J=12.4,2.0Hz,2H),4.74(dd,J=45.2,7.5Hz,2H ), 4.34(dt,J=29.3,11.2Hz,4H), 4.02(t,J=8.0Hz,2H), 3.77(t,J=14.6Hz,2H), 3.52(s,4H).

[0169] Embodiment 14

[0170] The synthetic route of this embodiment is shown in the figure below:

[0171]

[0172] 5) Preparation of water-soluble cationic photoinitiator

[0173] 5.1) In a dry three-necked flask, weigh 50.2 g of intermediate 5-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as solvent, and stir under nitrogen protection. Add 38.1 g of compound 5-4 (0.1 mol), and stir the mixture at room temperature for 8 h to ensure complete reaction.

[0174] 5.2) After the reaction, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-5. The final yield was 75.6 g, the yield was 86%, and the H NMR spectrum data was:

[0175] 1 H NMR (500MHz, Chloroform) δ8.86 (s, 1H), 8.31–7.78 (m, 3H), 7.06 (dd, J = 14.8, 2.9 Hz, 1H), 6.03 (ddt, J = 33.4, 19.8, 12. 3Hz, 1H), 5.50–4.49 (m, 6H), 4.31 (dt, J = 29.0, 11.1Hz, 4H), 3.99 (t, J = 8.0Hz, 2H), 3.74 (t, J = 14.4Hz, 2H), 3.50 (s, 4H).

[0176] Embodiment 15

[0177] The synthetic route of this embodiment is shown in the figure below:

[0178]

[0179] 5) Preparation of water-soluble cationic photoinitiator

[0180] 5.1) In a dry three-necked flask, weigh 51.6 g of intermediate 6-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as solvent, and stir under nitrogen protection. Add 38.1 g of compound 6-4 (0.1 mol), and stir the mixture at room temperature for 8 h to ensure complete reaction.

[0181] 5.2) After the reaction, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-6. The final yield was 77.1 g, the yield was 88%, and the H NMR spectrum data was:

[0182] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),8.37–8.09(m,2H),8.03(d,J=2.9Hz,1H),7.11(dd,J=15.0,2.9Hz,1H),6.23– 5.81(m,1H),5.60–4.76(m,6H),4.34(dt,J=20.8,9.1Hz,4H),3.85(dt,J=20.7,9.1Hz,4H),3.52(s,4H),0.94(s,3H).

[0183] Example 16

[0184] The synthetic route of this embodiment is shown in the figure below:

[0185]

[0186] 5) Preparation of water-soluble cationic photoinitiator

[0187] 5.1) In a dry three-necked flask, weigh 62.8 g of intermediate 7-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as solvent, and stir under nitrogen protection. Add 38.1 g of compound 7-4 (0.1 mol), and stir the mixture at room temperature for 10 hours to ensure complete reaction.

[0188] 5.2) After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-7. The final yield was 85.3 g, the yield was 85%, and the H NMR spectrum data was:

[0189] 1H NMR(500MHz,Chloroform)δ8.92(s,1H),8.39–7.85(m,3H),7.11(dd,J=15.0,2.9Hz,1H),6.07(ddt,J=33.3,19.8,12.4Hz,1H),5.67–4.5 7(m,6H),4.33(dt,J=13.4,7.4Hz,4H),4.03(t,J=8.2Hz,2H),3.77(t,J=6.6Hz,2H),3.52(s,4H),1.49–1.03(m,12H),1.04–0.64(m,6H).

[0190] Embodiment 17

[0191] The synthetic route of this embodiment is shown in the figure below:

[0192]

[0193] 5) Preparation of water-soluble cationic photoinitiator

[0194] 5.1) In a dry three-necked flask, weigh 68.4 g of intermediate 8-3 (0.1 mol), add an appropriate amount of anhydrous ethanol as a solvent, stir under nitrogen protection, add 38.1 g of compound 8-4 (0.1 mol), and stir the mixture at room temperature for 10 hours to ensure complete reaction.

[0195] 5.2) After the reaction was completed, the solvent was removed by rotary evaporation, and the residue was dissolved in deionized water and freeze-dried to obtain cationic photoinitiator Y-8. The final yield was 87.2 g, the yield was 82%, and the H NMR spectrum data was:

[0196] 1 H NMR(500MHz,Chloroform)δ8.91(s,1H),8.32–8.11(m,2H),8.02(d,J=2.9Hz,1H ),7.10(dd,J=15.0,2.9Hz,1H),6.07(ddt,J=33.3,19.8,12.4Hz,1H),5.55–4.94 (m,4H),4.73(ddd,J=44.1,7.5,0.6Hz,2H),4.47–4.16(m,4H),4.01(t,J=8.0Hz, 2H), 3.77 (t, J = 14.6Hz, 2H), 3.52 (s, 4H), 1.50–0.99 (m, 20H), 0.99–0.66 (m, 6H).

[0197] Embodiment 18

[0198] The synthetic route of this embodiment is shown in the figure below:

[0199]

[0200] 5) Preparation of water-soluble cationic photoinitiator

[0201] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 9-1 (0.1 mol), dissolve it in an appropriate amount of anhydrous ethanol as a solvent, slowly add 48.7 g of intermediate 1-3 (0.1 mol), and stir evenly at room temperature. The reaction system is heated to reflux under nitrogen protection and maintained for 6 hours to ensure complete reaction.

[0202] 5.2) After the reaction is completed, the mixture is cooled to room temperature, poured into ice water and stirred to precipitate solids, the solids are collected by filtration and repeatedly washed with deionized water until the filtrate is neutral; the obtained crude product is recrystallized from anhydrous ethanol to finally obtain 75.06 g of cationic photoinitiator Y-9 with a yield of 85%. The H NMR spectrum data is:

[0203] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),8.36–7.88(m,3H),7.11(dd,J=15.0,2.9Hz,1H),5.80(ddt,J=33.5,20.0,12.4Hz,1H),5.1 9–4.65(m,4H),4.50–4.19(m,4H),4.02(t,J=8.0Hz,2H),3.87–3.66(m,3H),3.58–3.39(m,5H),2.24(dtt,J=12.3,10.3,2.0Hz,2H).

[0204] Embodiment 19

[0205] The synthetic route of this embodiment is shown in the figure below:

[0206]

[0207] 5) Preparation of water-soluble cationic photoinitiator

[0208] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 10-1 (0.1 mol) and dissolve it in an appropriate amount of anhydrous ethanol as a solvent. Slowly add 51.6 g of intermediate 2-3 (0.1 mol) under stirring, and heat the reaction system to reflux under nitrogen protection, and keep the reaction for 6 hours to ensure the reaction is complete.

[0209] 5.2) After the reaction is completed, the reaction system is cooled to room temperature, the mixture is poured into ice water and stirred to precipitate solids, the product is collected by suction filtration, and repeatedly washed with deionized water until the filtrate is neutral. The obtained crude product is recrystallized with anhydrous ethanol to finally obtain 73.51 g of cationic photoinitiator Y-10, with a yield of 81%. The H NMR spectrum data is:

[0210] 1 H NMR (500MHz, Chloroform) δ8.92 (s, 1H), 8.37–7.90 (m, 3H), 7.11 (dd, J = 15.0, 2. 9Hz, 1H), 5.80 (ddt, J=33.6, 20.0, 12.5Hz, 1H), 4.96 (dddt, J=20.1, 18.2, 4.1, 2. 0Hz,2H),4.77(q,J=7.5Hz,2H),4.34(dt,J=29.3,11.2Hz,4H),4.01(t,J=8.1Hz ,2H),3.85–3.70(m,3H),3.62–3.40(m,5H),2.24(dtt,J=12.4,10.5,2.0Hz,2H).

[0211] Embodiment 20

[0212] The synthetic route of this embodiment is shown in the figure below:

[0213]

[0214] 5) Preparation of water-soluble cationic photoinitiator

[0215] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 11-1 (0.1 mol), add an appropriate amount of anhydrous acetone as solvent, stir under nitrogen protection, slowly add 54.3 g of intermediate 3-3 (0.1 mol), heat the reaction system to reflux, and maintain for 5 h to ensure complete reaction.

[0216] 5.2) After the reaction is completed, the reaction mixture is cooled to room temperature, and the reaction mixture is poured into ice water and stirred to precipitate solids. The product is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The crude product is recrystallized from anhydrous ethanol to finally obtain 71.06 g of cationic photoinitiator Y-11 with a yield of 76%. The H NMR spectrum data is:

[0217] 1H NMR(500MHz,Chloroform)δ8.92(s,1H),8.42–7.91(m,3H),7.11(dd,J=15.0,2.9Hz,1H),5.80(ddt,J=33.3,20.0, 12.3Hz,1H),5.15–4.61(m,4H),4.34(dt,J=25.2,7.6Hz,4H),4.09–3.42(m,10H),2.52–2.24(m,2H),0.94(s,6H).

[0218] Embodiment 21

[0219] The synthetic route of this embodiment is shown in the figure below:

[0220]

[0221] 5) Preparation of water-soluble cationic photoinitiator

[0222] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 12-1 (0.1 mol), add an appropriate amount of anhydrous acetone as solvent. Stir under nitrogen protection, and slowly add 54.3 g of intermediate 4-3 (0.1 mol). Heat the reaction system to reflux and maintain for 5 hours to ensure complete reaction.

[0223] 5.2) After the reaction is completed, the reaction mixture is cooled to room temperature, and the reaction mixture is poured into ice water and stirred to precipitate solids. The product is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The crude product is recrystallized from anhydrous ethanol to finally obtain 75.43 g of cationic photoinitiator Y-12 with a yield of 81%. The H NMR spectrum data is:

[0224] 1 H NMR(500MHz,Chloroform)δ8.90(s,1H),8.33–8.10(m,2H),8.01(d,J=3.1Hz,1H),7.09(dd,J=15.0, 3.1Hz,1H),5.79(ddt,J=33.3,20.0,12.4Hz,1H),4.94(dddt,J=19.9,18.2,4.1,2.0Hz,2H),4.58(d dd,J=17.2,7.5,0.6Hz,2H),4.33(dt,J=24.8,8.0Hz,4H),4.00(t,J=8.1Hz,2H),3.76(t,J=7.9Hz,2 H), 3.61 (t, J = 10.0Hz, 1H), 3.51 (s, 4H), 3.20 (t, J = 10.0Hz, 1H), 2.04 (dtt, J = 12.0, 10.0, 2.0Hz, 2H).

[0225] Embodiment 22

[0226] The synthetic route of this embodiment is shown in the figure below:

[0227]

[0228] 5) Preparation of water-soluble cationic photoinitiator

[0229] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 13-1 (0.1 mol), add an appropriate amount of anhydrous ethanol as solvent. Stir under nitrogen protection, and slowly add 50.2 g of intermediate 5-3 (0.1 mol). Heat the reaction system to reflux and keep stirring for 6 hours to ensure the reaction is complete.

[0230] 5.2) After the reaction is completed, cool to room temperature, pour the reaction mixture into ice water and stir to precipitate solid. Collect the product by filtration and wash repeatedly with deionized water until the filtrate is neutral. The crude product is recrystallized from anhydrous ethanol to finally obtain 77.09g of cationic photoinitiator Y-13 with a yield of 87%. The H NMR spectrum data is:

[0231] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),8.43–7.81(m,3H),7.11(dd,J=15.0,2.9H z,1H),5.80(ddt,J=33.3,20.0,12.3Hz,1H),5.11–4.74(m,2H),4.65(ddd,J=37.7 ,7.5,0.6Hz,2H),4.34(dt,J=28.2,11.0Hz,4H),4.02(t,J=7.9Hz,2H),3.84–3.66 (m,3H),3.52(s,4H),3.44(t,J=10.2Hz,1H),2.19(dtt,J=12.1,10.2,1.8Hz,2H).

[0232] Embodiment 23

[0233] The synthetic route of this embodiment is shown in the figure below:

[0234]

[0235] 5) Preparation of water-soluble cationic photoinitiator

[0236] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 14-1 (0.1 mol), add an appropriate amount of anhydrous acetone as solvent. Stir under nitrogen protection, and slowly add 51.6 g of intermediate 6-3 (0.1 mol). Heat the reaction system to reflux temperature and keep the reaction for 8 hours to ensure the complete reaction.

[0237] 5.2) After the reaction is completed, cool to room temperature, pour the reaction mixture into ice water and stir to generate solid. Collect the product by filtration and wash repeatedly with deionized water until the filtrate is neutral. The crude product is recrystallized from anhydrous ethanol to finally obtain 76.69 g of cationic photoinitiator Y-14 with a yield of 84%. The H NMR spectrum data is:

[0238] 1 H NMR(500MHz,Chloroform)δ8.90(s,1H),8.38–7.83(m,3H),7.09(dd,J=14.9,3.0Hz, 1H),5.79(ddt,J=33.6,20.0,12.4Hz,1H),4.95(dddt,J=19.9,18.0,4.1,2.0Hz,2H), 4.68(dd,J=25.3,7.5Hz,2H),4.33(dt,J=29.7,11.4Hz,4H),4.05(t,J=8.4Hz,2H),3. 88–3.64(m,3H),3.62–3.24(m,5H),2.24(dtt,J=12.1,10.2,1.9Hz,2H),0.94(s,3H).

[0239] Embodiment 24

[0240] The synthetic route of this embodiment is shown in the figure below:

[0241]

[0242] 5) Preparation of water-soluble cationic photoinitiator

[0243] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 15-1 (0.1 mol), add an appropriate amount of anhydrous ethanol as solvent. Stir under nitrogen protection, and slowly add 62.8 g of intermediate 7-3 (0.1 mol). Heat the reaction system to reflux temperature and keep the reaction for 10 hours to ensure that the reaction is complete.

[0244] 5.2) After the reaction is completed, the reaction mixture is cooled to room temperature and poured into ice water and stirred to generate solid. The product is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The crude product is recrystallized with anhydrous ethanol to finally obtain 88.22 g of cationic photoinitiator Y-15 with a yield of 87%. The H NMR spectrum data is:

[0245] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),8.38–7.94(m,3H),7.11(dd,J=15.0,2.9Hz,1H),5.99–5.62(m,1H),5.13–4.61(m,4H),4.48 –4.23(m,4H),4.02(t,J=8.2Hz,2H),3.86–3.64(m,3H),3.58–3.31(m,5H),2.41–2.06(m,2H),1.42–1.07(m,12H),1.01–0.68(m,6H).

[0246] Embodiment 25

[0247] The synthetic route of this embodiment is shown in the figure below:

[0248]

[0249] 5) Preparation of water-soluble cationic photoinitiator

[0250] 5.1) In a dry three-necked flask, weigh 39.6 g of compound 16-1 (0.1 mol), add an appropriate amount of anhydrous ethanol as a solvent. Stir under nitrogen protection, and slowly add 68.4 g of intermediate 8-3 (0.1 mol). Heat the reaction system to reflux temperature and keep the reaction for 10 hours to ensure that the reaction is complete.

[0251] 5.2) After the reaction is completed, the reaction mixture is cooled to room temperature and poured into ice water and stirred to generate solid. The product is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The crude product is recrystallized with anhydrous ethanol to finally obtain 91.8 g of cationic photoinitiator Y-16 with a yield of 85%. The H NMR spectrum data is:

[0252] 1H NMR(500MHz,Chloroform)δ8.92(s,1H),8.40–7.88(m,3H),7.11(dd,J=15.0,3.1Hz,1H),5.80(ddt,J=33.3,19.8,12.3Hz,1 H),4.96(dddt,J=20.1,18.2,4.1,1.9Hz,2H),4.67–3.29(m,16H),2.46–1.97(m,2H),1.49–1.05(m,19H),1.00–0.61(m,6H).

[0253] Performance Testing

[0254] (I) Solubility and dispersibility test: Evaluate the solubility or dispersibility of Y1-Y16 in water.

[0255] Experimental steps:

[0256] 1. Sample preparation: Weigh Y1 to Y16 and prepare solutions with concentrations of 1 mg / mL, 5 mg / mL, and 10 mg / mL, respectively.

[0257] 2. Stirring and dissolving: Add samples Y1 to Y16 into water and stir using a magnetic stirrer for 30 minutes to ensure complete dissolution.

[0258] 3. Solubility evaluation: The state of each solution was visually observed and the dissolution of Y1 to Y16 in water was recorded.

[0259] (ii) Photoinitiation efficiency experiment: Determine the initiation efficiency of Y1~Y16 under ultraviolet light and evaluate their performance under different illumination times and concentrations.

[0260] Experimental steps:

[0261] 1. Sample preparation: Prepare a solution containing acrylate monomer (PEGDA), and add Y1 to Y16 respectively to prepare a mixed solution with a concentration of 1 wt%.

[0262] 2. UV curing: Place the above samples in a quartz vial and use a UV curing system (wavelength 365nm, light intensity 500mW / cm 2 ) Irradiate the sample with ultraviolet light and record the light response after 5 minutes.

[0263] 3. FT-IR monitoring: Use Fourier transform infrared spectrometer to monitor the polymerization reaction in real time, detect the intensity change of the characteristic peak of acrylate C=C double bond (about 1630 cm-1), and calculate the initiation efficiency.

[0264] (III) Initiator migration experiment: Based on the material synthesis, evaluate whether T1~T16 migrate after the polymer is cured, verify its initiation efficiency and judge its stability.

[0265] Experimental steps:

[0266] 1. Film preparation: A mixture of Y1-Y16 and vinyl ether monomers is cured by a UV curing system to prepare a polymer film.

[0267] 2. Immersion experiment: The prepared polymer films were immersed in water for 24 h, 48 h and 72 h respectively.

[0268] 3. Absorption peak detection: Take out solution samples every 24 hours, use UV-visible spectrometer to detect whether there is photoinitiator in the immersion solution, and evaluate the migration by detecting the changes in characteristic absorption peaks.

[0269] The experimental results are shown in the following table.

[0270]

[0271]

[0272] From the above experimental results, it can be seen that: Y-1~Y-16 show good solubility and dispersibility in water, ensuring the uniformity of the system during the photocuring process. At the same time, the initiation efficiency of Y-1~Y-16 is ≥84%, with good photoinitiation ability, suitable for photocuring applications of epoxy resins, vinyl ether systems, etc.; finally, Y1~Y-16 show the characteristics of basically no migration after the polymer film is cured, which is suitable for fields with strict requirements on mobility such as food packaging and medical coatings.

[0273] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also change and modify the above implementation modes. Therefore, the present invention is not limited to the specific implementation modes disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A cationic photoinitiator intermediate, characterized in that: Its molecular structure is shown in formula 3: Wherein, R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups.

2. The cationic photoinitiator intermediate according to claim 1, characterized in that The alkyl group is C n H m , where n and m are both independently natural numbers less than 30; The molecular structure of the oligoether group is Here, m is a natural number less than 30.

3. The cationic photoinitiator intermediate according to claim 1, characterized in that: The cationic photoinitiator intermediate is one of the following formulas 1-3 to 8-3:

4. The method for preparing the cationic photoinitiator intermediate according to claims 1 to 3, characterized in that: At least the following steps are included: 1) Compound B-1 is dissolved in an organic solvent, cooled to 0-5°C, and phosgene and aluminum chloride as shown in formula B-2 are slowly added as catalysts, the molar ratio of compound B-1 to phosgene B-2 is 1:1-1.5, stirred for 3-5 hours, and then the reactants are poured into ice water for neutralization, and then liquid-liquid extraction, drying and rotary evaporation are performed to obtain intermediate B-3; 2) Dissolve the intermediate B-3 in an organic solvent, add N-bromosuccinimide and benzoyl peroxide in a molar ratio of 1:1 to 1.5, stir for 1 to 3 hours at a system temperature of ≤0°C, and then heat to The mixture was stirred at room temperature for 3 to 5 hours. After the reaction, the mixture was neutralized with sodium carbonate and subjected to liquid-liquid extraction to obtain intermediate B-4, the structure of which is shown in formula B-4: 3) The intermediate B-4 is dissolved in an organic solvent, and dialkyl sulfide R1SR2 and potassium hexafluoroantimonate are added, the molar ratio of the intermediate B-4, dialkyl sulfide R1SR2 and potassium hexafluoroantimonate is 1:1-1.5:1-1.5, and the reaction is stirred at room temperature for 7-9 hours, and then poured into ice water to precipitate a solid, and the solid is filtered, washed and dried to obtain an intermediate 2, whose molecular structure is shown in 2: Wherein, R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups; 4) The intermediate 2 is dissolved in an organic solvent, cooled to ≤0°C, and boron tribromide is slowly added dropwise, the molar ratio of the intermediate 2 to boron tribromide is 1:1-1.5, stirred for 0.5-1.5h, then warmed to room temperature, and continued to stir for 5-7h; after the reaction, the mixture is poured into ice water for neutralization, and a cationic photoinitiator intermediate 3 is obtained by liquid-liquid extraction, drying and recrystallization, and its molecular structure is shown in 3: Wherein, R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups.

5. The method for preparing a cationic photoinitiator intermediate according to claim 4, characterized in that: The alkyl group is C n H m , where n and m are both independently natural numbers less than 30; The molecular structure of the oligoether group is Here, m is a natural number less than 30.

6. A water-soluble cationic photoinitiator, characterized in that: Its molecular structure is shown in formula Y: Among them, R is * is the link position, n is a natural number greater than 1 and less than 30; R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups.

7. The water-soluble cationic photoinitiator according to claim 6, characterized in that: The alkyl group is C n H m , where n and m are both independently natural numbers less than 30; The molecular structure of the oligoether group is Here, m is a natural number less than 30.

8. The water-soluble cationic photoinitiator according to claim 6 or 7, characterized in that: Its molecular structure is one of the following formulas Y-1 to Y-16:

9. A method for preparing a water-soluble cationic photoinitiator, characterized in that: At least the following steps are included: 1) preparing the cationic photoinitiator intermediate 3 according to claim 1; 2) The cationic photoinitiator intermediate 3 is dissolved in an organic solvent, and then an imidazole derivative is added, the molar ratio of the cationic photoinitiator intermediate 3 to the imidazole derivative is 1:1-1.5, the system temperature is heated to 75-85°C, and the reaction is stirred for 11-13 hours. After cooling, the organic solvent is removed by rotary evaporation, and the water-soluble cationic photoinitiator is washed and recrystallized to obtain a water-soluble cationic photoinitiator, whose molecular structure is shown in Formula Y: Among them, R is * is the link position, n is a natural number greater than 1 and less than 30; R1 and R2 are independently alkyl, cyano, aryl, substituted aryl, benzyl, substituted benzyl or oligoether groups.

10. The method for preparing a water-soluble cationic photoinitiator according to claim 9, characterized in that: In step 2), the molecular structure of the imidazole derivative is shown in 4:

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