Thioxanthone modified photoinitiator intermediate and preparation method thereof, and water-soluble polymerizable photoinitiator and preparation method thereof

Abstract

The invention discloses a thioxanthone modified photoinitiator intermediate and a preparation method thereof, and the molecular structure of the thioxanthone modified photoinitiator intermediate is shown as a formula A-6. The invention also discloses a water-soluble polymerizable photoinitiator prepared from the photoinitiator intermediate, the molecular structure of the water-soluble polymerizable photoinitiator is shown as a formula T, the molecular structure of the photoinitiator is specifically designed, so that the photoinitiator is remarkably improved in the aspects of spectral absorption, solubility and migration stability compared with the prior art, and high initiation efficiency, good water solubility and low migration of visible light are realized; the water-soluble polymerizable photoinitiator can be widely applied to water-based photocureable coatings, environment-friendly printing ink and other industrial applications with high requirements for safety and stability and has remarkable technical improvement and practical value, and the invention further discloses a preparation method of the water-soluble polymerizable photoinitiator.

Description

Technical Field

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

[0002] Photoinitiators are a class of compounds that initiate chemical reactions by absorbing light energy. They are widely used in photocuring systems, including coatings, inks, optical fiber coatings, and 3D printing. However, with the escalating demands for environmental protection and industrial production, the shortcomings of traditional photoinitiators in certain aspects have gradually become apparent, especially in aqueous systems. The solubility of photoinitiators, their responsiveness to visible light, and the stability of the final product have become issues that need to be urgently addressed.

[0003] Common photoinitiators are mostly ketone compounds, such as benzoin and benzoin derivatives, especially "9H-thioxanthene-9-one" and its derivatives (also known as thioxanthone and thioxanthone), which have high initiation efficiency in the ultraviolet light region and have therefore become one of the most widely used commercial photoinitiators on the market.

[0004] Based on its unique molecular structure, thioxanthone can efficiently generate free radicals under ultraviolet light to initiate polymerization reactions of monomers such as acrylates, showing excellent photoinitiating ability. Its stable structure and good photochemical reaction properties make it widely used in traditional photocuring applications, such as UV coatings and inks.

[0005] However, traditional thioxanthone photoinitiators still have the following shortcomings:

[0006] 1. Insufficient spectral absorption range: Existing thioxanthone and its derivatives have high initiation efficiency in the ultraviolet region, that is, they are mainly sensitive to ultraviolet light, and have low initiation efficiency in the visible light region, which limits their applications using visible light sources (such as LED lights). Modern industry gradually tends to use visible light sources to reduce dependence on ultraviolet light, thereby improving operational safety and environmental protection. However, existing photoinitiators do not perform well under such conditions, which restricts the expansion of their application scenarios.

[0007] 2. Poor water solubility: Traditional photoinitiators (including thioxanthone) have poor solubility in water and are difficult to use in environmentally friendly water-based coatings. They require a large amount of organic solvents or additives to assist in dissolution, which is obviously contrary to the current environmental protection trend.

[0008] 3. Migration problem: After the polymerization reaction, the traditional thioxanthone photoinitiator is prone to migration in the curing material because its chemical structure is not covalently bonded to the polymer main chain, which is a long-standing safety hazard. For example, the patent document with announcement number CN107400112B discloses a photoinitiator and its preparation method. The photoinitiator achieves long-wave absorption based on the thioxanthone parent core and has strong absorption of 395nm UV LED light source. The photoinitiator is endowed with low surface tension by introducing fluorocarbon chains, so that the photoinitiator can float to the surface of the coating / ink layer in the formulation system, that is, the photoinitiator can be enriched on the surface, and a high concentration of free radicals is generated on the surface after absorbing light to resist surface oxygen inhibition.

[0009] The photoinitiator in the above-mentioned prior art contains a quaternary ammonium group, which is connected to the thioxanthone aromatic ring through a methylene group. This structure has photosensitive decomposition characteristics, but the molecular structure of the photoinitiator has no polymerizable group, so it cannot be covalently bonded to the main chain of other organic polymers in the formulation system, and is easy to migrate in the curing material. The migration of the photoinitiator will cause harmful residues in the curing material, making the final product fail to meet the requirements of environmental regulations or safety standards, and is not suitable for use in fields with high safety requirements such as food and medicine. Summary of the invention

[0010] In response to the problems in the related art, the present invention is based on the molecular structure of "9H-thioxanthene-9-one". The present invention proposes a thioxanthene-modified photoinitiator intermediate and a preparation method thereof. At the same time, the present invention also discloses a water-soluble polymerizable photoinitiator prepared by the above-mentioned photoinitiator intermediate and a preparation method thereof. Through the optimization and improvement of the molecular structure, the photoinitiator has high initiation efficiency to visible light, good water solubility and low mobility, thereby meeting the needs of modern water-based photocuring systems and overcoming the above-mentioned technical problems existing in the existing related technologies.

[0011] The technical solution of the present invention is achieved in this way:

[0012] A thioxanthone-modified photoinitiator intermediate, the molecular structure of which is shown in Formula A-6:

[0013]

[0014] The above-mentioned thioxanthone-modified photoinitiator intermediate comprises the following steps:

[0015] 1) A compound with a molecular structure as shown in formula A-1 is reacted with phosphorus pentasulfide (P2S5) at a substance amount ratio of 1:1 to 1.2 to obtain an intermediate A-2, whose molecular structure is shown in formula A-2; in this step, phosphorus pentasulfide acts as a deoxidizing agent to convert the carbonyl group in compound A-1 into a thiocarbonyl group, thereby forming an aromatic structure having a thiocarbonyl group.

[0016]

[0017] 2) Intermediate A-2 is subjected to a demethylation reaction under boron tribromide (BBr3) conditions to obtain intermediate A-3; boron tribromide is used as a demethylating agent to remove the methoxy group on the aromatic ring, exposing the phenolic hydroxyl group, thereby providing an active site for subsequent functionalization reactions.

[0018]

[0019] 3) Intermediate A-3 is reacted with an alkoxy compound containing a bromine group, whose molecular structure is shown in formula A-4, in a molar ratio of 1:1 to 1.2 to produce intermediate A-5 containing an alkoxy group; by introducing the alkoxy group, the solubility of the molecule and the activity of subsequent reactions are increased.

[0020]

[0021] 4) The intermediate A-5 undergoes a substitution reaction with an imidazole compound at a molar ratio of 1:1 to 1.2 to obtain a thioxanthone-modified photoinitiator intermediate A-6 containing an imidazole group; this reaction introduces the imidazole group, enhances the polarity of the molecule, and lays the foundation for the subsequent introduction of an ionic liquid unit.

[0022]

[0023] Preferably, steps 1) to 4) are all carried out under the protection of an inert gas with stirring.

[0024] Preferably, the step 1) comprises the following steps:

[0025] 1.1) The compound with the molecular structure shown in formula A-1 is first dissolved in anhydrous toluene, stirred under nitrogen protection, and then phosphorus pentasulfide (P2S5) is slowly added, and then the system is heated to 90-110°C and kept reacting at this temperature for 3-5 hours;

[0026] 1.2) After the reaction is completed, the mixture is cooled to room temperature and poured into ice water with stirring to generate a solid. The solid is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The obtained product is recrystallized to obtain intermediate A-2.

[0027] Preferably, the step 2) comprises the following steps:

[0028] 2.1) Intermediate A-2 is first dissolved in anhydrous dichloromethane, stirred under nitrogen protection, the reaction system temperature is ≤ 0°C, and boron tribromide (BBr3) is slowly added dropwise;

[0029] 2.2) After the addition is completed, gradually warm up to room temperature and stir the reaction at this temperature for 11 to 13 hours;

[0030] 2.3) After the reaction is completed, the reaction system is carefully poured into an excess of deionized water, which is placed in an ice-water bath and stirred to precipitate a solid. The solid is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The resulting product is recrystallized to obtain intermediate A-3.

[0031] Preferably, the step 3) comprises the following steps:

[0032] 3.1) The intermediate A-3 is first dissolved in anhydrous toluene, and stirred under nitrogen protection, and the bromine-containing alkoxy compound A-4 and triethylamine are slowly added, and then the system is heated to 75-85°C and stirred at this temperature for 5-7h;

[0033] 3.2) After the reaction is completed, the reaction mixture is cooled to room temperature and separated by adding an appropriate amount of deionized water. The organic phase is taken, dried and then the solvent is evaporated under reduced pressure. The obtained crude product is recrystallized to obtain intermediate A-5.

[0034] Preferably, the step 4) comprises the following steps:

[0035] 4.1) Intermediate A-5 is first dissolved in anhydrous dimethyl sulfoxide (DMSO), stirred under nitrogen protection, and the imidazole compound is slowly added, and then the system is heated to 100°C and stirred at this temperature for 7 to 9 hours;

[0036] 4.2) After the reaction is completed, the reaction mixture is cooled to room temperature, and an appropriate amount of cold water is added to precipitate solids. The product is collected by filtration, and repeatedly washed with deionized water until the filtrate is neutral. The obtained product is recrystallized to obtain a thioxanthone-modified photoinitiator intermediate A-6.

[0037] The present invention also discloses a water-soluble polymerizable photoinitiator, the molecular structure of which is shown in Formula T:

[0038]

[0039] Among them, X ˉ is at least one of fluoride, chloride, bromide, iodide, phosphate, sulfonate, carbonate, hexafluorophosphate or nitrate;

[0040] The structure of R is * is the linking position, and R' is an alkyl group, a cyano group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group or an oligoether group.

[0041] Preferably, the alkyl group is C n H m, where n and m are independently natural numbers less than 30.

[0042] Preferably, the molecular structure of the oligoether group is Here, m is a natural number less than 30.

[0043] Preferably, the water-soluble polymerizable photoinitiator is one of the following formulas T-1 to T-16:

[0044]

[0045] The maximum absorption wavelength range of the water-soluble polymerizable photoinitiator is 300-500 nm, and the absorbance is ≥0.90.

[0046] The preparation method of the water-soluble polymerizable photoinitiators T1 to T8 comprises at least the following steps:

[0047] 1) preparing the above-mentioned thioxanthone-modified photoinitiator intermediate A-6;

[0048] 2) The intermediate A-6 is subjected to an alkylation reaction with a brominated compound containing an acrylate group at a substance amount ratio of 1:1 to 1.2 to obtain a water-soluble polymerizable photoinitiator, whose molecular structure is shown in Formula A-8; this step introduces a polymerizable double bond so that the final product can be covalently bonded to the polymer matrix during the photocuring process.

[0049]

[0050] The structure of R is * is the linking position, and R' is an alkyl group, a cyano group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group or an oligoether group.

[0051] The preparation method of the water-soluble polymerizable photoinitiators T9 to T16 comprises at least the following steps:

[0052] 1) Prepare the above-mentioned thioxanthone-modified photoinitiator intermediate A-6.

[0053] 2) The intermediate A-6 is subjected to an alkylation reaction with a brominated compound containing an acrylate group at a molar ratio of 1:1 to 1.2 to obtain an intermediate A-8, whose molecular structure is shown in Formula A-8; this step introduces a polymerizable double bond so that the final product can be covalently bonded to the polymer matrix during the photocuring process.

[0054]

[0055] The structure of R is * is the linking position, and R' is an alkyl group, a cyano group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group or an oligoether group.

[0056] 3) Intermediate A-8 and ammonium salt NH4X are subjected to ion exchange reaction at a substance amount ratio of 1:1 to 1.2 to obtain a water-soluble polymerizable photoinitiator; wherein X is at least one of fluoride ion, chloride ion, iodide ion, phosphate, sulfonate, carbonate, hexafluorophosphate or nitrate. Through the ion exchange reaction, specific anions are introduced to further optimize the solubility and application characteristics of the final photoinitiator.

[0057] 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.

[0058] Preferably, the ammonium salt is ammonium hexafluorophosphate.

[0059] Preferably, step 2) of the above two preparation methods is carried out under the protection of an inert gas with stirring.

[0060] More preferably, step 2) of the above two preparation methods comprises the following steps:

[0061] 2.1) Dissolve the photoinitiator intermediate A-6 prepared in step 1)1 in toluene, stir and react under nitrogen protection, then add the brominated compound containing an acrylate group, and stir and react at room temperature for 11 to 13 hours;

[0062] 2.2) After the reaction is completed, the solvent is removed, the product is dissolved in water, the solution is concentrated to obtain a crude product, and the obtained crude product is recrystallized to obtain a water-soluble polymerizable photoinitiator or intermediate A-8.

[0063] Preferably, in step 2) of the above two preparation methods, the preparation method of the brominated compound containing an acrylate group comprises the following steps:

[0064] a) acryloyl chloride or a derivative of acryloyl chloride and 2-bromoethanol are mixed and dissolved in an organic solvent at a molar ratio of 0.8-1.2:0.8-1.2;

[0065] b) Start stirring and keep heating to 80-90°C, and stir for 5-7h;

[0066] c) After the reaction is completed, the feed solution is cooled to room temperature, and then an inorganic salt solution is added to quench the reaction;

[0067] d) separating the organic phase from the liquid obtained in step c), washing and drying the organic phase, removing the organic solvent, and purifying to obtain a brominated compound containing an acrylate group.

[0068] Preferably, the organic solvent in step a) is toluene; and the inorganic salt solution in step c) is a saturated sodium chloride solution.

[0069] Preferably, in step 2) of the above two preparation methods, the brominated compound containing acrylate is one of the following formulas 1-3 to 8-3:

[0070]

[0071] Preferably, the method for preparing the water-soluble polymerizable photoinitiators T9 to T16, step 3) thereof comprises the following steps:

[0072] 3.1) Dissolve intermediate A-8 in water, slowly add ammonium salt under stirring, and react at room temperature for 7 to 9 hours;

[0073] 3.2) removing water from the solution obtained in step 3.1) to obtain a crude product, and washing the crude product to obtain an aqueous polymerizable thioxanthone photoinitiator.

[0074] The general synthesis formula of the water-soluble polymerizable photoinitiator of the present invention is shown below:

[0075]

[0076] Beneficial effects of the present invention:

[0077] First, the water-soluble polymerizable photoinitiator prepared by the photoinitiator intermediate of the present invention replaces the carbonyl group in the thioxanthone molecular structure with a thiocarbonyl group. Since the electronegativity of sulfur is less than that of oxygen, the energy required for the electron transition of the carbon-sulfur double bond by the subsequently synthesized photoinitiator is lower, thereby shifting the spectral absorption toward the long wavelength direction, so that the photoinitiator of the present invention exhibits a higher initiation efficiency in the visible light region, and is suitable for diversified light sources in modern industry, especially environmentally friendly LED light sources.

[0078] Secondly, the water-soluble polymerizable photoinitiator of the present invention further introduces ionic liquid functional groups into the molecular structure, which significantly improves its solubility in water and meets the requirements of the water-based photocuring system. The ionic liquid group provides excellent hydrophilicity, so that the photoinitiator prepared by the present invention can be evenly dispersed in water, which not only reduces the dependence on organic solvents, but also makes the application more environmentally friendly and economical.

[0079] Finally, the water-soluble polymerizable photoinitiator of the present invention also introduces a polymerizable double bond, so that the water-soluble polymerizable photoinitiator of the present invention can be covalently bonded to the polymer matrix during the photocuring process, thereby significantly reducing its migration behavior after curing, improving the physicochemical stability and safety of the final material, and is particularly suitable for applications with strict requirements on mobility, such as food packaging and medical materials.

[0080] In summary, the water-soluble polymerizable photoinitiator of the present invention has significantly improved spectral absorption, solubility and migration stability compared with the prior art, achieving high initiation efficiency for visible light, good water solubility and low mobility, and can be widely used in water-based photocurable coatings, environmentally friendly inks and other industrial applications with high requirements for safety and stability, and has significant technical improvements and practical value. DETAILED DESCRIPTION

[0081] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments. 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.

[0082] Example 1

[0083] The synthetic route of this embodiment is shown below:

[0084]

[0085] 1) Preparation of intermediate A-2

[0086] 1.1) In a dry three-necked flask, weigh 242.29 g of compound A-1 (1 mol), add an appropriate amount of anhydrous toluene as solvent, and stir under nitrogen protection; slowly add 444.5 g of phosphorus pentasulfide (P2S5, 1 mol), then heat the system to 100°C and keep the reaction at this temperature for 4 hours.

[0087] 1.2) After the reaction is completed, the mixture is cooled to room temperature and poured into ice water with stirring to generate solids. The solids are collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The obtained product is recrystallized from ethanol to finally obtain 212.57 g of intermediate A-2, and the H NMR spectrum data is:

[0088] 1 H NMR (500MHz, DMSO-d6) δ8.05(d,J=8.4Hz,1H),7.62–7.50(m,2H),7.32(t,J=7.6Hz,1H),7.18(d,J=8.0Hz,1H),6.92(s,1H),4.45(s,2H).

[0089] 2) Preparation of intermediate A-3

[0090] 2.1) In a dry three-necked flask, weigh 183.25g of intermediate A-2 (0.75mol), add an appropriate amount of anhydrous dichloromethane as solvent, stir under nitrogen protection, slowly add 188g of boron tribromide (BBr3, 0.75mol), and add dropwise while keeping the reaction system temperature at 0°C.

[0091] 2.2) After the dropwise addition was completed, the temperature was gradually raised to room temperature and the reaction was stirred at this temperature for 12 h.

[0092] 2.3) After the reaction is completed, the reaction system is carefully poured into an excess of deionized water in an ice water bath and stirred to precipitate solids. The solids are collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The obtained product is recrystallized from ethanol to finally obtain 163.18 g of intermediate A-3 with a yield of 89%. The H NMR spectrum data is:

[0093] 1 H NMR (500MHz, DMSO-d6) δ9.02 (s, 1H), 7.88–7.65 (m, 3H), 7.55 (d, J = 8.0Hz, 1H), 7.42 (t, J = 7.6Hz, 1H), 6.97 (s, 1H).

[0094] 3) Preparation of intermediate A-5

[0095] 3.1) In a dry three-necked flask, weigh 122.17 g of intermediate A-3 (0.5 mol), add an appropriate amount of anhydrous toluene as solvent, and stir under nitrogen protection; slowly add bromoalkoxy compound A-4 (137.99 g, 0.5 mol) and triethylamine (51 g, 0.5 mol), then heat the system to 80°C and stir the reaction at this temperature for 6 hours.

[0096] 3.2) After the reaction is completed, the reaction mixture is cooled to room temperature, and an appropriate amount of deionized water is added to separate the organic phase, which is dried over anhydrous sodium sulfate and then evaporated under reduced pressure to remove the solvent. The resulting crude product is recrystallized from ethanol to finally obtain 205.19 g of intermediate A-5 with a yield of 93%. The H NMR spectrum data is:

[0097] 1 H NMR (500MHz, DMSO-d6) δ7.92(d,J=8.4Hz,1H),7.58–7.46(m,3H),7.23(t,J=7.6Hz,1H),6.89(s,1H),4.25(t,J=6.8Hz,2H),3.82(t,J=6.8Hz,2H).

[0098] 4) Preparation of intermediate A-6

[0099] 4.1) In a dry three-necked flask, weigh 175.75 g of intermediate A-5 (0.4 mol), add an appropriate amount of anhydrous dimethyl sulfoxide (DMSO) as a solvent, and stir under nitrogen protection; slowly add 27.2 g of imidazole compound (0.4 mol), then heat the system to 100°C and stir the reaction at this temperature for 8 hours.

[0100] 4.2) After the reaction is completed, the reaction mixture is cooled to room temperature, and an appropriate amount of cold water is added to precipitate solids. The product is collected by filtration and repeatedly washed with deionized water until the filtrate is neutral. The obtained product is recrystallized from ethanol to finally obtain 188.26 g of thioxanthone-modified photoinitiator intermediate A-6, with a yield of 95%. The H NMR spectrum data is:

[0101] 1 H NMR (500MHz, DMSO-d6) δ8.10(s,1H),7.72(d,J=8.4Hz,1H),7.58–7.45(m,3H),7.20(s,1H),6.85(s,1H),4.56(t,J=6.8Hz,2H),3.78(t,J=6.8Hz,2H).

[0102] Example 2

[0103] The synthetic route of this embodiment is shown below:

[0104]

[0105] 5) Preparation of brominated compounds containing acrylate groups

[0106] 5.1) Weigh 114g of compound 1-1 (1.0mol), dissolve it in 200mL of anhydrous toluene, place it in a three-necked flask, and install it in a condenser reflux device. Weigh 125g of compound 1-2 (1.0mol), slowly add it to the 1-1 solution under stirring, stir evenly, and continue stirring at room temperature for 30min to ensure that the reactants are fully mixed.

[0107] 5.2) The reaction mixture was then heated to 90°C and maintained at this temperature for 6 hours to promote the reaction, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0108] 5.3) After the reaction is completed, stop heating and cool the reaction mixture to room temperature, then add 300 mL of saturated sodium chloride solution.

[0109] 5.4) Separate the organic phase using a separatory funnel, wash the organic phase three times with 200 mL of deionized water to remove water-soluble byproducts or impurities, then dry it with anhydrous sodium sulfate for 1 hour and filter it to remove the desiccant.

[0110] 5.5) The organic phase was evaporated to remove toluene under reduced pressure on a rotary evaporator to obtain a crude product. The crude product was recrystallized using water as a solvent to finally obtain 193 g of a purified brominated compound 1-3 containing an acrylate group, and the H NMR spectrum data were:

[0111] 1 H NMR (500MHz, DMSO-d6) δ6.42 (d, J = 15.6 Hz, 1H), 6.10 (d, J = 15.6 Hz, 1H), 3.78 (s, 4H), 2.85 (t, J = 6.5 Hz, 2H).

[0112] 6) Preparation of water-soluble polymerizable photoinitiator

[0113] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, stir under nitrogen protection, then add 48.25 g of the brominated compound 1-3 (0.25 mol), and stir the reaction at room temperature for 12 h.

[0114] 6.2) After the reaction is completed, the solvent is removed, the product is dissolved in water, and the solution is further concentrated by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized from ethanol to finally obtain 134.73 g of water-soluble polymerizable photoinitiator T-1, with a yield of 89%. The H NMR spectrum data is:

[0115] 1 H NMR (500MHz, Chloroform) δ8.92 (s, 1H), 7.43–6.95 (m, 6H), 6.60 (d, J = 3.1Hz, 1H), 6.44 (ddd, J = 40.3, 4.1, 2.1Hz, 2H), 4.95–4. 67 (m, 4H), 4.47 (t, J = 9.2Hz, 2H), 4.32 (dt, J = 8.0, 7.2Hz, 4H), 3.80 (dt, J = 12.5, 7.2Hz, 4H), 3.52 (s, 4H), 2.01 (t, J = 2.0Hz, 3H).

[0116] Example 3

[0117] The synthetic route of this embodiment is shown below:

[0118]

[0119] 5) Preparation of brominated compounds containing acrylate groups

[0120] 5.1) Weigh 118g of compound 2-1 (1.0mol), dissolve it in 200mL of anhydrous toluene, place it in a three-necked flask, and install it in a condenser reflux device. Weigh 125g of compound 2-2 (1.0mol), slowly add it to the 2-1 solution under stirring, stir evenly, and continue stirring at room temperature for 30min to ensure that the reactants are fully mixed.

[0121] 5.2) The reaction mixture was then heated to 90°C and maintained at this temperature for 6 hours to promote the reaction, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0122] 5.3) After the reaction is completed, stop heating and cool the reaction mixture to room temperature, then add 300 mL of saturated sodium chloride solution.

[0123] 5.4) Separate the organic phase using a separatory funnel, wash the organic phase three times with 200 mL of deionized water to remove water-soluble byproducts or impurities, then dry it with anhydrous sodium sulfate for 1 hour and filter it to remove the desiccant.

[0124] 5.5) The organic phase was evaporated under reduced pressure on a rotary evaporator to remove toluene to obtain a crude product. The crude product was recrystallized using water as a solvent to finally obtain 134 g of a purified brominated compound 2-3 containing an acrylate group, and the H NMR spectrum data were:

[0125] 1 H NMR(500MHz,Chloroform)δ6.29(dt,J=4.1,2.0Hz,1H),5.46(dt,J=4.1,2.0Hz,1H),4.64(t, J=15.0Hz, 2H), 3.65 (t, J=15.0Hz, 2H), 2.44 (qd, J=13.4, 11.5Hz, 2H), 1.07 (t, J=13.4Hz, 3H).

[0126] 6) Preparation of water-soluble polymerizable photoinitiator

[0127] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, stir under nitrogen protection, then add 51.75 g of the brominated compound 2-3 (0.25 mol), and stir the reaction at room temperature for 12 h.

[0128] 6.2) After the reaction is completed, the solvent is removed, the product is dissolved in water, and the solution is further concentrated by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized from ethanol to finally obtain 141.8 g of water-soluble polymerizable photoinitiator T-2, with a yield of 81%. The nuclear magnetic resonance hydrogen spectrum data is:

[0129] 1 H NMR (500MHz, Chloroform) δ8.92 (s, 1H), 7.43–6.95 (m, 6H), 6.60 (d, J = 3.1Hz, 1H), 6.44 (ddd, J = 40.3, 4.1, 2.1Hz, 2H), 4.95–4. 67 (m, 4H), 4.47 (t, J = 9.2Hz, 2H), 4.32 (dt, J = 8.0, 7.2Hz, 4H), 3.80 (dt, J = 12.5, 7.2Hz, 4H), 3.52 (s, 4H), 2.01 (t, J = 2.0Hz, 3H).

[0130] Example 4

[0131] The synthetic route of this embodiment is shown below:

[0132]

[0133] 5) Preparation of brominated compounds containing acrylate groups

[0134] 5.1) Weigh 146g of compound 3-1 (1.0mol), dissolve in 300mL of anhydrous toluene, place in a three-necked flask, and install in a condensation reflux device. Weigh 125g of compound 3-2 (1.0mol), slowly add to the 3-1 solution under stirring, the whole addition process lasts for 30min, and ensure that the two are fully mixed.

[0135] 5.2) After the addition is completed, the reaction mixture is heated to 90°C and maintained for 8 hours to promote the reaction. During this period, the reaction progress is monitored by thin layer chromatography (TLC) and an appropriate developing agent is selected to observe the separation of reactants and products.

[0136] 5.3) After the reaction was completed, the reaction mixture was cooled to room temperature and 300 mL of saturated sodium chloride solution was added.

[0137] 5.4) Separate the layers using a separatory funnel to separate the organic phase. Wash the organic phase three times with 200 mL of deionized water to remove water-soluble impurities, dry the organic phase with anhydrous sodium sulfate for 1 hour, and filter to remove the desiccant.

[0138] 5.5) The organic phase was placed in a rotary evaporator, and toluene was distilled off under reduced pressure to obtain a crude product. The crude product was recrystallized using ethanol as a solvent to finally obtain 134 g of a purified brominated compound 3-3 containing an acrylate group, and the H NMR spectrum data were:

[0139] 1H NMR(500MHz,Chloroform)δ6.29(dt,J=4.1,2.0Hz,1H),5.46(dt,J=4.1,2.0Hz,1H),4.64(t,J=8.0Hz ,2H),3.65(t,J=8.0Hz,2H),2.41(tt,J=11.2,1.8Hz,2H),1.62–1.09(m,4H),0.93(t,J=12.6Hz,3H).

[0140] 6) Preparation of water-soluble polymerizable photoinitiator

[0141] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, and stir under nitrogen protection. Then add 58.5 g of the brominated compound 3-3 (0.25 mol), and stir the reaction at room temperature for 12 h to ensure that the reaction is complete.

[0142] 6.2) After the reaction is completed, the solvent is removed and the product is dissolved in deionized water to obtain an aqueous solution of the product. Water is removed by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized with ethanol to finally obtain 136.3 g of water-soluble polymerizable photoinitiator T-3 with a yield of 85%. The H NMR spectrum data is:

[0143] 1 H NMR(500MHz,Chloroform)δ8.91(s,1H),7.47–6.91(m,6H),6.59(d,J=2.9Hz,1 H),6.28(dt,J=4.1,2.0Hz,1H),5.45(dt,J=4.1,2.0Hz,1H),5.28–5.10(m,1H) ,4.73(t,J=8.2Hz,2H),4.55–4.15(m,7H),3.78(dt,J=15.7,8.4Hz,4H),3.52( s,4H),2.41(tt,J=11.0,1.8Hz,2H),1.48–1.11(m,4H),0.93(t,J=12.6Hz,3H).

[0144] Example 5

[0145] The synthetic route of this embodiment is shown below:

[0146]

[0147] 5) Preparation of brominated compounds containing acrylate groups

[0148] 5.1) Weigh 160g of compound 4-1 (1.0mol), dissolve it in 300mL of anhydrous toluene, place it in a three-necked flask, and install a condenser reflux device. Weigh 125g of compound 4-2 (1.0mol), slowly add it to the 4-1 solution under stirring conditions, and the entire addition process lasts for 30min to ensure that the two are fully mixed.

[0149] 5.2) After the addition was completed, the reaction mixture was heated to 90° C. and maintained for 8 h to promote the reaction, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0150] 5.3) After the reaction was completed, the reaction mixture was cooled to room temperature and 300 mL of saturated sodium chloride solution was added.

[0151] 5.4) Separate the organic phase using a separatory funnel. Wash the organic phase three times with 200 mL of deionized water to remove water-soluble impurities. Dry the organic phase with anhydrous sodium sulfate for 1 h and filter to remove the desiccant.

[0152] 5.5) The organic phase was placed in a rotary evaporator, and toluene was distilled off under reduced pressure to obtain a crude product. The crude product was finally purified by column chromatography using petroleum ether / ethyl acetate as eluent to obtain 213 g of brominated compound 4-3 containing an acrylate group, and the H NMR spectrum data were:

[0153] 1 H NMR(500MHz,Chloroform)δ6.29(dt,J=4.1,2.0Hz,1H),5.46(dt,J=4.0,1.9Hz,1H),4.64(t,J=7.7Hz,2H),3.6 5(t,J=7.6Hz,2H),2.41(tt,J=11.6,1.9Hz,2H),1.77–1.42(m,1H),1.40–1.22(m,2H),0.91(d,J=12.5Hz,6H).

[0154] 6) Preparation of water-soluble polymerizable photoinitiator

[0155] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, and stir under nitrogen protection. Then add 62.0 g of the brominated compound 4-3 (0.25 mol), and stir the reaction at room temperature for 12 h to ensure that the reaction is complete.

[0156] 6.2) After the reaction is completed, the solvent is removed and the product is dissolved in deionized water to obtain an aqueous solution of the product. Water is removed by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized with ethanol to finally obtain 151.4 g of water-soluble polymerizable photoinitiator T-4, with a yield of 90%. The H NMR spectrum data is:

[0157] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),7.43–7.32(m,2H),7.27–6.94(m,4H),6.60(d,J=2.9Hz,1H),6.2 9(dt,J=4.1,2.0Hz,1H),5.46(dt,J=4.1,2.0Hz,1H),4.89(d,J=7.5Hz,1H),4.82(d,J=7.5Hz,1H),4.74( t,J=8.4Hz,2H),4.47(t,J=8.4Hz,2H),4.32(dt,J=8.5,7.7Hz,4H),3.90–3.62(m,4H),3.52(s,4H),2.41 (tt,J=15.1,1.8Hz,2H),1.77–1.40(m,1H),1.30(ddd,J=15.5,13.5,0.6Hz,2H),0.91(d,J=12.5Hz,6H).

[0158] Example 6

[0159] The synthetic route of this embodiment is shown below:

[0160]

[0161] 5) Preparation of brominated compounds containing acrylate groups

[0162] 5.1) Weigh 166g of compound 5-1 (1.0 mol), dissolve in 300mL of anhydrous toluene, place in a three-necked flask, and install a condenser reflux device. Weigh 125g of compound 5-2 (1.0 mol), slowly add to the 5-1 solution under stirring, and the entire addition process lasts for 30 minutes to ensure that the two are fully mixed.

[0163] 5.2) After the addition was completed, the reaction mixture was heated to 90° C. and maintained for 8 h to promote the reaction, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0164] 5.3) After the reaction was completed, the reaction mixture was cooled to room temperature and 300 mL of saturated sodium chloride solution was added.

[0165] 5.4) Separate the organic phase using a separatory funnel. Wash the organic phase three times with 200 mL of deionized water to remove water-soluble impurities. Dry the organic phase with anhydrous sodium sulfate for 1 h and filter to remove the desiccant.

[0166] 5.5) The organic phase was placed in a rotary evaporator, and toluene was distilled off under reduced pressure to obtain a crude product. The crude product was finally purified by column chromatography using petroleum ether / ethyl acetate as eluent to obtain 225 g of brominated compound 5-3 containing an acrylate group, and the H NMR spectrum data were:

[0167] 1 H NMR (500MHz, Chloroform) δ 7.59–7.26 (m, 3H), 7.29–6.89 (m, 2H), 6.28 (dd, J = 51.1, 4.2Hz, 2H), 4.64 (t, J = 8.0Hz, 2H), 3.65 (t, J = 8.0Hz, 2H).

[0168] 6) Preparation of water-soluble polymerizable photoinitiator

[0169] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, and stir under nitrogen protection. Then add 63.75 g of the brominated compound 5-3 (0.25 mol), and stir the reaction at room temperature for 12 h to ensure that the reaction is complete.

[0170] 6.2) After the reaction is completed, the solvent is removed and the product is dissolved in deionized water to obtain an aqueous solution of the product. Water is removed by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized with ethanol to finally obtain 145.4 g of water-soluble polymerizable photoinitiator T-5 with a yield of 86%. The H NMR spectrum data is:

[0171] 1 H NMR(500MHz,Chloroform)δ8.89(s,1H),7.44–6.93(m,11H),6.55(dd,J=33.0,3.5Hz,2H),6.12(d,J=4.2Hz,1H), 5.03–4.65(m,4H),4.46(t,J=7.3Hz,2H),4.31(dt,J=8.4,7.2Hz,4H),3.78(dt,J=12.8,7.2Hz,4H),3.51(s,4H).

[0172] Example 7

[0173] The synthetic route of this embodiment is shown below:

[0174]

[0175] 5) Preparation of brominated compounds containing acrylate groups

[0176] 5.1) Weigh 180g of compound 6-1 (1.0mol), dissolve it in 300mL of anhydrous toluene, place it in a three-necked flask, and install a condenser reflux device. Weigh 125g of compound 6-2 (1.0mol), slowly add it to the solution of 6-1 under stirring conditions, and the entire addition process lasts for 30min to ensure that the two are fully mixed.

[0177] 5.2) After the addition was completed, the reaction mixture was heated to 90° C. and maintained for 8 h to promote the reaction, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0178] 5.3) After the reaction was completed, the reaction mixture was cooled to room temperature and 300 mL of saturated sodium chloride solution was added.

[0179] 5.4) Separate the organic phase using a separatory funnel. Wash the organic phase three times with 200 mL of deionized water to remove water-soluble impurities. Dry the organic phase with anhydrous sodium sulfate for 1 h and filter to remove the desiccant.

[0180] 5.5) The organic phase was placed in a rotary evaporator, and toluene was distilled off under reduced pressure to obtain a crude product. The crude product was finally purified by column chromatography using petroleum ether / ethyl acetate as eluent to obtain 215 g of brominated compound 6-3 containing an acrylate group, and the H NMR spectrum data were:

[0181] 1 H NMR (500MHz, Chloroform) δ7.39–6.91 (m, 4H), 6.26 (dd, J = 74.5, 4.2Hz, 2H), 4.64 (t, J = 13.6Hz, 2H), 3.65 (t, J = 13.6Hz, 2H), 2.41 (s, 3H).

[0182] 6) Preparation of water-soluble polymerizable photoinitiator

[0183] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, and stir under nitrogen protection. Then add 67.00 g of the brominated compound 6-3 (0.25 mol), and stir the reaction at room temperature for 12 h to ensure that the reaction is complete.

[0184] 6.2) After the reaction is completed, the solvent is removed and the product is dissolved in deionized water to obtain an aqueous solution of the product. Water is removed by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized with ethanol to finally obtain 140.8 g of water-soluble polymerizable photoinitiator T-6, with a yield of 81%. The nuclear magnetic resonance hydrogen spectrum data is:

[0185] 1 H NMR(500MHz,Chloroform)δ8.89(s,1H),7.42–6.88(m,10H),6.57(d,J=2.9Hz,1H),5.92(d,J=4.2Hz,1H), 5.68(d,J=4.2Hz,1H),4.78–4.54(m,2H),4.53–4.08(m,8H),3.83–3.63(m,4H),3.51(s,4H),2.40(s,3H).

[0186] Example 8

[0187] The synthetic route of this embodiment is shown below:

[0188]

[0189] 5) Preparation of brominated compounds containing acrylate groups

[0190] 5.1) Weigh 180g of compound 7-1 (1.0mol), dissolve it in 300mL of anhydrous toluene, place it in a three-necked flask, and install a condenser reflux device. Weigh 125g of compound 7-2 (1.0mol), slowly add it to the solution of 7-1 under stirring, and the whole addition process lasts for 30min to ensure that the two are fully mixed.

[0191] 5.2) After the addition was completed, the reaction mixture was heated to 90° C. and maintained for 8 h to promote the reaction, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0192] 5.3) After the reaction was completed, the reaction mixture was cooled to room temperature and 300 mL of saturated sodium chloride solution was added.

[0193] 5.4) Separate the organic phase using a separatory funnel. Wash the organic phase three times with 200 mL of deionized water to remove water-soluble impurities. Dry the organic phase with anhydrous sodium sulfate for 1 h and filter to remove the desiccant.

[0194] 5.5) The organic phase was placed in a rotary evaporator, and toluene was distilled off under reduced pressure to obtain a crude product. The crude product was finally purified by column chromatography using petroleum ether / ethyl acetate as eluent to obtain 241 g of brominated compound 7-3 containing an acrylate group, and the H NMR spectrum data were:

[0195] 1 H NMR (500MHz, Chloroform) δ7.57–6.84(m,5H),6.12(dt,J=4.1,1.9Hz,1H),5.40(dt,J=4.1,2.0Hz,1H),4.64(t,J=15.0Hz,2H),3.83–3.33(m,4H).

[0196] 6) Preparation of water-soluble polymerizable photoinitiator

[0197] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, and stir under nitrogen protection. Then add 67.00 g of the brominated compound 7-3 (0.25 mol), and stir the reaction at room temperature for 12 h to ensure that the reaction is complete.

[0198] 6.2) After the reaction is completed, the solvent is removed and the product is dissolved in deionized water to obtain an aqueous solution of the product. Water is removed by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized with ethanol to finally obtain 146.0 g of water-soluble polymerizable photoinitiator T-7 with a yield of 84%. The H NMR spectrum data is:

[0199] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),7.46–6.89(m,11H),6.60(d,J=2.9Hz,1H),6.12(dt,J=4.1,2.0Hz,1H),5.40(dt,J=4.1,2.0Hz,1H) ,4.86(ddd,J=22.9,13.3,6.0Hz,4H), 4.47(t,J=11.4Hz,2H), 4.32(dt,J=10.2,7.6Hz,4H), 3.80(dt,J=27.9,7.5Hz,4H), 3.61–3.40(m,6H).

[0200] Example 9

[0201] The synthetic route of this embodiment is shown below:

[0202]

[0203] 5) Preparation of brominated compounds containing acrylate groups

[0204] 5.1) Weigh 114g of compound 8-1 (1.0mol), dissolve in 300mL of anhydrous toluene, place in a three-necked flask, and install a condenser reflux device. Weigh 125g of compound 8-2 (1.0mol), slowly add to the solution of 8-1 under stirring, and the whole addition process lasts for 30min to ensure that the two are fully mixed.

[0205] 5.2) After the addition was completed, the reaction mixture was heated to 90° C. and kept reacting for 8 h, during which the reaction progress was monitored by thin layer chromatography (TLC).

[0206] 5.3) After the reaction was completed, the reaction mixture was cooled to room temperature and 300 mL of saturated sodium chloride solution was added.

[0207] 5.4) Separate the organic phase using a separatory funnel. Wash the organic phase three times with 200 mL of deionized water to remove water-soluble impurities. Dry the organic phase with anhydrous sodium sulfate for 1 h and filter to remove the desiccant.

[0208] 5.5) The organic phase was placed in a rotary evaporator, and toluene was distilled off under reduced pressure to obtain a crude product. The crude product was finally purified by column chromatography using petroleum ether / ethyl acetate as eluent to obtain 174 g of brominated compound 8-3 containing an acrylate group, and the H NMR spectrum data were:

[0209] 1 H NMR (500MHz, Chloroform) δ6.99 (d, J = 4.2 Hz, 1H), 6.56 (d, J = 4.0 Hz, 1H), 4.65 (t, J = 15.0 Hz, 2H), 3.65 (t, J = 15.0 Hz, 2H).

[0210] 6) Preparation of water-soluble polymerizable photoinitiator

[0211] 6.1) In a dry three-necked flask, weigh 106.63 g of the photoinitiator intermediate A-6 (0.25 mol) prepared in Example 1, add an appropriate amount of anhydrous toluene as a solvent, and stir under nitrogen protection. Then add 51.00 g of the brominated compound 8-3 (0.25 mol), and stir the reaction at room temperature for 12 h to ensure that the reaction is complete.

[0212] 6.2) After the reaction is completed, the solvent is removed and the product is dissolved in deionized water to obtain an aqueous solution of the product. Water is removed by rotary evaporation to obtain a crude product. The obtained crude product is recrystallized from ethanol to finally obtain 136.4 g of water-soluble polymerizable photoinitiator T-8, with a yield of 88%. The H NMR spectrum data is:

[0213] 1H NMR(500MHz,Chloroform)δ8.90(s,1H),7.37(dd,J=15.1,1.6Hz,2H),7.27–6.81(m,5H),6.56(dd,J=22.8,3.6Hz,2H),5.50(dd ,J=7.5,0.6Hz,1H),5.00–4.72(m,3H),4.46(t,J=8.4Hz,2H),4.31(ddd,J=8.9,6.8,1.4Hz,4H),3.93–3.67(m,4H),3.51(s,4H).

[0214] Example 10

[0215] The synthetic route of this embodiment is shown below:

[0216]

[0217] 7.1) In a dry single-necked flask, weigh 61.8 g of T-1 (0.1 mol) obtained in Example 2, add an appropriate amount of deionized water as a solvent, and stir at room temperature until it is completely dissolved. Then add 16.3 g of ammonium hexafluorophosphate (0.1 mol), and continue to stir and react at room temperature for 8 h.

[0218] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 61.6 g of water-soluble polymerizable photoinitiator T-9 with a yield of 90%. The H NMR spectrum data is:

[0219] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),7.46–7.30(m,2H),7.29–6.87(m,4H),6.60(d,J=3.1Hz,1H),6.44(ddq,J=40.3,4.0,2.0Hz,2H),4.86(t,J= 8.8Hz,2H),4.75–4.58(m,2H),4.47(t,J=8.8Hz,2H),4.32(dt,J=8.8,7.2 Hz, 4H), 3.80 (dt, J = 13.2, 7.2 Hz, 4H), 3.52 (s, 4H), 2.01 (t, J = 2.0 Hz, 3H).

[0220] Embodiment 11

[0221] The synthetic route of this embodiment is shown below:

[0222]

[0223] 7.1) In a dry single-necked flask, weigh 63.2 g of T-2 (0.1 mol) obtained in Example 3, add an appropriate amount of deionized water as a solvent, and stir at room temperature until it is completely dissolved. Then add 16.3 g of ammonium hexafluorophosphate (0.1 mol), and continue to stir at room temperature for 8 hours to ensure that the reaction is complete.

[0224] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 58.0 g of water-soluble polymerizable photoinitiator T-10 with a yield of 83%. The H NMR spectrum data is:

[0225] 1 H NMR(500MHz,Chloroform)δ8.91(s,1H),7.38(dd,J=15.1,1.6Hz,2H),7.27–6.87(m,4H), 6.59(d,J=3.1Hz,1H),6.28(dt,J=4.0,1.9Hz,1H),5.45(dt,J=4.1,2.0Hz,1H),4.99–4.8 2(m,2H),4.74(t,J=8.0Hz,2H),4.47(t,J=8.0Hz,2H),4.32(dt,J=9.2,7.4Hz,4H),3.78( dt,J=11.3,7.5Hz,4H),3.52(s,4H),2.44(qt,J=13.4,1.9Hz,2H),1.07(t,J=13.4Hz,3H).

[0226] Example 12

[0227] The synthetic route of this embodiment is shown below:

[0228]

[0229] 7.1) In a dry single-necked flask, weigh 66.0 g of T-3 (0.1 mol) obtained in Example 4, add an appropriate amount of deionized water as a solvent, and stir at room temperature until it is completely dissolved. Then add 16.3 g of ammonium hexafluorophosphate (0.1 mol), and continue to stir at room temperature for 8 hours to ensure that the reaction is complete.

[0230] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 62.4 g of water-soluble polymerizable photoinitiator T-11 with a yield of 86%. The H NMR spectrum data is:

[0231] 1H NMR(500MHz,Chloroform)δ8.91(s,1H),7.50–6.88(m,6H),6.59(d,J=3.0Hz,1H) ,6.28(dt,J=4.1,2.0Hz,1H),5.45(dt,J=4.1,2.0Hz,1H),4.93(d,J=7.5Hz,1H), 4.72(t,J=8.1Hz,2H),4.52–4.11(m,7H),3.79(dt,J=14.8,7.7Hz,4H),3.52(s,4 H), 2.42 (ddd, J=16.9, 9.2, 7.4Hz, 2H), 1.60–1.15 (m, 4H), 0.93 (t, J=12.8Hz, 3H).

[0232] Embodiment 13

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

[0234]

[0235] 7.1) In a dry single-necked flask, weigh 67.4 g of T-4 (0.1 mol) obtained in Example 5, add an appropriate amount of deionized water as a solvent, and stir at room temperature until completely dissolved. Then, weigh 16.3 g of ammonium hexafluorophosphate (0.1 mol) and add it to the flask, and continue to stir and react at room temperature for 8 hours to ensure that the reaction is complete.

[0236] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 63.2 g of water-soluble polymerizable photoinitiator T-12 with a yield of 87%. The H NMR spectrum data is:

[0237] 1 H NMR(500MHz,Chloroform)δ8.91(s,1H),7.51–6.86(m,6H),6.59(d,J=3.0Hz,1H), 6.28(dt,J=4.1,2.0Hz,1H),5.45(dt,J=4.1,2.0Hz,1H),4.93(d,J=7.5Hz,1H),4.7 2(t,J=8.1Hz,2H),4.53–4.16(m,7H),3.79(dt,J=14.8,7.7Hz,4H),3.52(s,4H),2 .42(ddd,J=16.9,9.2,7.4Hz,2H),1.56–1.11(m,4H),0.93(dd,J=16.2,9.3Hz,3H).

[0238] Embodiment 14

[0239] The synthetic route of this embodiment is shown below:

[0240]

[0241] 7.1) In a dry single-necked flask, weigh 68.0 g of T-5 (0.1 mol) obtained in Example 6, add an appropriate amount of deionized water as a solvent, and stir at room temperature until it is completely dissolved. Then, weigh 16.3 g of ammonium hexafluorophosphate (0.1 mol) and add it to the flask, and continue to stir the reaction at room temperature for 8 hours to ensure that the reaction is completely carried out.

[0242] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 60.4 g of water-soluble polymerizable photoinitiator T-13 with a yield of 81%. The H NMR spectrum data is:

[0243] 1 H NMR(500MHz,Chloroform)δ8.86(s,1H),7.44–6.85(m,11H),6.55(d,J=2.9Hz,1H),6.33(d,J=4.2Hz,1H),6.19(d,J=4.2Hz,1H),5.42(d d,J=7.5,0.6Hz,1H),4.91–4.64(m,3H),4.44(t,J=10.1Hz,2H),4.29(dt,J=8.4,7.4Hz,4H),3.77(dt,J=13.1,7.3Hz,4H),3.49(s,4H).

[0244] Embodiment 15

[0245] The synthetic route of this embodiment is shown below:

[0246]

[0247] 7.1) In a dry single-necked flask, weigh 69.5 g of T-6 (0.1 mol) prepared in Example 7, add an appropriate amount of deionized water as a solvent, and stir at room temperature until completely dissolved. Then, weigh 16.3 g of ammonium hexafluorophosphate (0.1 mol) and add it to the flask, and continue to stir and react at room temperature for 8 hours to ensure that the reaction is complete.

[0248] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 65.4 g of water-soluble polymerizable photoinitiator T-14 with a yield of 86%. The H NMR spectrum data is:

[0249] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),7.47–6.88(m,10H),6.60(d,J=2.9Hz,1H),6.21(dd,J =57.0,4.2Hz,2H),4.94–4.05(m,10H),3.78(dt,J=14.9,7.6Hz,4H),3.52(s,4H),2.41(s,3H).

[0250] Example 16

[0251] The synthetic route of this embodiment is shown below:

[0252]

[0253] 7.1) In a dry single-necked flask, weigh 69.5 g of T-7 (0.1 mol) obtained in Example 8, add an appropriate amount of deionized water as a solvent, and stir at room temperature until it is completely dissolved. Then, weigh 16.3 g of ammonium hexafluorophosphate (0.1 mol) and add it to the flask, and continue to stir and react at room temperature for 8 hours to ensure that the ion exchange reaction is completely carried out.

[0254] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 62.3 g of water-soluble polymerizable photoinitiator T-15 with a yield of 82%. The H NMR spectrum data is:

[0255] 1 H NMR(500MHz,Chloroform)δ8.91(s,1H),7.49–6.80(m,11H),6.59(d,J=2.9Hz,1H),6.11(dt,J=4.0,2.0Hz,1H),5.39(dt,J =4.1,2.0Hz,1H),4.80(ddd,J=27.5,19.8,8.5Hz,4H),4.57–4.15(m,6H),3.78(dt,J=11.9,7.3Hz,4H),3.60–3.34(m,6H).

[0256] Embodiment 17

[0257] The synthetic route of this embodiment is shown below:

[0258]

[0259] 7.1) In a dry single-necked flask, weigh 62.9 g of T-8 (0.1 mol) prepared in Example 9, add an appropriate amount of deionized water as a solvent, and stir at room temperature until completely dissolved. Then, weigh 16.3 g of ammonium hexafluorophosphate (0.1 mol) and add it to the flask, and continue to stir and react at room temperature for 8 hours to ensure that the ion exchange reaction is completely carried out.

[0260] 7.2) After the reaction is completed, water is removed by rotary evaporation to obtain a crude product. The crude product is washed with a small amount of anhydrous ethanol to finally obtain 58.4 g of water-soluble polymerizable photoinitiator T-16 with a yield of 84%. The H NMR spectrum data is:

[0261] 1 H NMR(500MHz,Chloroform)δ8.92(s,1H),7.54–6.85(m,6H),6.62(dd,J=15.5,3.6Hz,2H),6.25(d ,J=4.0Hz,1H),5.01–4.67(m,4H),4.58–4.22(m,6H),3.80(dt,J=14.4,7.7Hz,4H),3.52(s,4H).

[0262] Performance Testing

[0263] (I) Solubility and dispersibility experiments: Evaluate the solubility or dispersibility of T1-T16 in water to determine their application potential in water-based photocuring systems.

[0264] Experimental steps:

[0265] 1. Sample preparation: Weigh T1 to T16 and prepare solutions with concentrations of 1 mg / mL, 5 mg / mL, and 10 mg / mL, respectively.

[0266] 2. Stirring and dissolving: Add samples T1 to T16 into deionized water and stir with a magnetic stirrer for 30 minutes to ensure complete dissolution.

[0267] 3. Solubility evaluation: The state of each solution was visually observed and the dissolution of T1 to T16 in water was recorded.

[0268] 4. UV-Visible spectroscopy: Use a UV-Visible spectrometer to measure the absorbance of each sample at the maximum absorption wavelength.

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

[0270]

[0271]

[0272] (ii) Photoinitiation efficiency experiment: Determine the initiation efficiency of T1~T16 under ultraviolet light and evaluate their performance under different illumination times and concentrations.

[0273] Experimental steps:

[0274] 1. Sample preparation: Prepare a solution containing acrylate monomer (PEGDA), and add T1 to T16 respectively to prepare a mixed solution with a concentration of 1 wt%.

[0275] 2. Light curing: Place the above samples in a quartz vial and use a UVLED curing system (wavelength 365nm, light intensity 500mW / cm 2 ) Irradiate the sample with ultraviolet light and record the light response after 5 minutes.

[0276] 3. Viscosity measurement: Measure the viscosity change of the solution after different illumination times.

[0277] 4. FT-IR monitoring: Use Fourier transform infrared spectrometer to monitor the polymerization reaction in real time and detect the characteristic peak of acrylate C=C double bond (about 1630cm -1 ) intensity change and calculate the initiation efficiency.

[0278] 5.DSC exothermic measurement: Differential scanning calorimetry (DSC) was used to measure the exothermicity of the polymerization reaction and to evaluate the reaction rate.

[0279] The experimental results are shown in the following table.

[0280] The photoinitiator number contained in the sample C=C double bond conversion rate (%) Heat release (J / g) T-1 88 240 T-2 90 250 T-3 93 280 T-4 87 230 T-5 91 265 T-6 95 285 T-7 89 235 T-8 92 260 T-9 94 275 T-10 86 220 T-11 90 245 T-12 93 270 T-13 88 225 T-14 91 255 T-15 94 280 T-16 87 240

[0281] (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.

[0282] Experimental steps:

[0283] 1. Film preparation: A mixture of the above-mentioned T1-T16 with a concentration of 1 wt % and acrylate monomers was cured by a UVLED curing system to prepare a polymer film.

[0284] 2. Immersion experiment: The prepared polymer film was immersed in ethanol or water for 24 h, 48 h and 72 h respectively.

[0285] 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.

[0286] 4. HPLC detection: Use high performance liquid chromatography (HPLC) to quantitatively analyze the concentration of the photoinitiator in the immersion solution.

[0287] The experimental results are shown in the following table.

[0288]

[0289]

[0290] The above experimental results show that: (1) T1~T16 have good solubility in water and can be evenly dissolved, which is suitable for water-based photocuring applications; (2) The photoinitiation efficiency experiment shows that T1~T16 has excellent initiation performance and fast photocuring speed, showing high polymerization efficiency. The maximum absorption wavelength range of T1~T16 is 409~442nm, and the absorbance is 0.90~1.06; (3) Among T1~T16, most of the photoinitiators hardly migrate in the cured polymer film, showing excellent migration resistance, indicating that T1~T16 are suitable for applications with strict requirements on the mobility of the photoinitiator.

[0291] 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 thioxanthone-modified photoinitiator intermediate, characterized in that: Its molecular structure is shown in formula A-6:

2. The method for preparing the thioxanthone-modified photoinitiator intermediate according to claim 1, characterized in that: At least the following steps are included: 1) reacting a compound with a molecular structure as shown in formula A-1 with phosphorus pentasulfide at a molar ratio of 1:1 to 1.2 to obtain an intermediate A-2; 2) intermediate A-2 is subjected to a demethylation reaction under boron tribromide (BBr3) conditions to obtain intermediate A-3; 3) Intermediate A-3 and an alkoxy compound containing a bromine group, whose molecular structure is shown in formula A-4, are subjected to a nucleophilic substitution reaction at a molar ratio of 1:1 to 1.2 to generate an intermediate A-5 containing an alkoxy group; 4) The intermediate A-5 undergoes a substitution reaction with an imidazole compound at a molar ratio of 1:1 to 1.2 to obtain a thioxanthone-modified photoinitiator intermediate A-6 containing an imidazole group.

3. The method for preparing a thioxanthone-modified photoinitiator intermediate according to claim 2, characterized in that: Steps 1) to 4) are all stirred and reacted under the protection of an inert gas.

4. A water-soluble polymerizable photoinitiator, characterized in that: Its molecular structure is shown in formula T: Wherein, Xˉ is at least one of fluoride, chloride, bromide, iodide, phosphate, sulfonate, carbonate, hexafluorophosphate or nitrate; The structure of R is * is the linking position, and R' is an alkyl group, a cyano group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group or an oligoether group.

5. The water-soluble polymerizable photoinitiator according to claim 4, characterized in that: It is one of formula T-1 to formula T-16:

6. A method for preparing a water-soluble polymerizable photoinitiator, characterized in that: At least the following steps are included: 1) preparing the thioxanthone-modified photoinitiator intermediate A-6 according to claim 1; 2) The intermediate A-6 is subjected to an alkylation reaction with a brominated compound containing an acrylate group at a substance amount ratio of 1:1 to 1.2 to obtain a water-soluble polymerizable photoinitiator, the molecular structure of which is shown in Formula A-8: The structure of R is * is the linking position, and R' is an alkyl group, a cyano group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group or an oligoether group.

7. The method for preparing a water-soluble polymerizable photoinitiator according to claim 6, characterized in that: In step 2), the brominated compound containing acrylate is one of the following formulas 1-3 to 8-3:

8. The method for preparing a water-soluble polymerizable photoinitiator according to claim 6 or 7, characterized in that: Step 2) stirring the reaction under the protection of an inert gas.

9. A method for preparing a water-soluble polymerizable photoinitiator, characterized in that: At least the following steps are included:. 1) preparing the above-mentioned thioxanthone-modified photoinitiator intermediate A-6; 2) The intermediate A-6 is subjected to an alkylation reaction with a brominated compound containing an acrylate group at a molar ratio of 1:1 to 1.2 to obtain an intermediate A-8, the molecular structure of which is shown in Formula A-8: The structure of R is * is the linking position, R' is an alkyl group, a cyano group, an aryl group, a substituted aryl group, a benzyl group, a substituted benzyl group or an oligoether group; 3) intermediate A-8 and ammonium salt NH4X are subjected to ion exchange reaction at a substance amount of 1:1 to 1.2 to obtain a water-soluble polymerizable photoinitiator; Wherein, X is at least one of fluoride ion, chloride ion, iodide ion, phosphate, sulfonate, carbonate, hexafluorophosphate or nitrate.

10. The method for preparing a water-soluble polymerizable photoinitiator according to claim 9, characterized in that: In step 2), the brominated compound containing acrylate is one of the following formulas 1-3 to 8-3:

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