Process for the preparation of photoinitiator 369

Abstract

The application discloses a preparation method of a photoinitiator 369 and belongs to the field of photoinitiator preparation. The preparation method comprises the following steps: (1) Ullmann C-N coupling of chlorobenzene and morpholine under the action of a first catalyst to obtain N-phenyl morpholine; (2) performing a Friedel-Crafts reaction on the N-phenyl morpholine and phenylalanine to prepare a compound I; (3) performing an aminomethylation reaction on the compound I, formic acid and formaldehyde to prepare a compound II; and (4) reacting the compound II with iodoethane to obtain a crude photoinitiator 369. By implementing the application, the process route can be simplified, the use of fluorobenzene, bromine and the like can be avoided, and the yield is improved.

Description

Technical Field

[0001] This invention relates to the field of photoinitiators, and more particularly to a method for preparing photoinitiator 369. Background Technology

[0002] 2-Phenylen-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone (369) is a highly efficient photoinitiator with a high photosensitive range and good UV absorption. It has the characteristics of low migration and low odor, and is particularly suitable for rapid curing of dark-colored systems.

[0003] Existing patent reports on the preparation methods of photoinitiator 369 include: US20200002554 / US10961405 / WO2018163442 / WO2019198489 / CN111954849 / JP6497484 / KR2019124208 / CN103360272 / CN105384707 / CN108358871 / CN116332877, etc. In the above patents, fluorobenzene is mostly used as a starting material. 4-fluorophenylbutanone is obtained under the catalysis of anhydrous aluminum chloride. After bromination, a brominated product is obtained. The brominated product is then amination with dimethylamine to obtain an aminated product. The aminated product reacts with chlorobenzene to obtain a quaternary ammonium salt. The quaternary ammonium salt undergoes catalytic rearrangement under alkaline conditions to obtain a rearranged compound. The rearranged compound then undergoes a substitution reaction with morpholine to obtain photoinitiator 369.

[0004] This synthetic route uses fluorobenzene, which is expensive, resulting in high overall production costs. Furthermore, the wastewater generated during the final reaction with morpholine contains fluoride ions. Current national environmental regulations are strict, making the treatment of this fluoride ion wastewater troublesome and costly. Additionally, bromine is highly toxic and corrosive, requiring sophisticated equipment. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing photoinitiator 369, which has low raw material cost, high yield, simple process route, low equipment requirements, and is easy to mass-produce.

[0006] To address the technical problem of this invention, this invention provides a method for preparing photoinitiator 369, which includes the following steps:

[0007] (1) Chlorobenzene and morpholine undergo Ullmann CN coupling under the action of the first catalyst to obtain N-phenylmorpholine;

[0008] (2) N-phenylmorpholine and phenylalanine were reacted by Friedel-Crafts reaction to prepare compound I;

[0009]

[0010] (3) Compound I undergoes aminomethylation reaction with formic acid and formaldehyde to obtain compound II;

[0011]

[0012] (4) Compound II reacts with iodoethane to give crude photoinitiator 369.

[0013] As an improvement to the above technical solution, in step (1), chlorobenzene and morpholine are dissolved in a first solvent, and a first acid-binding agent and a first catalyst are added. The mixture is refluxed at 60–90°C for 8–16 hours. After the reaction is completed, the first solvent is separated to obtain N-phenylmorpholine; and / or

[0014] In step (2), N-phenylmorpholine and phenylalanine are dissolved in a second solvent, and a second catalyst is added. The mixture is reacted at -20 to 0°C for 2 to 8 hours. The second solvent is then separated to obtain compound I; and / or

[0015] In step (3), compound I is mixed with formic acid and a 20-60 wt% aqueous formaldehyde solution, and refluxed at 80-100°C for 2-5 hours to obtain compound II; and / or

[0016] In step (4), compound II is dissolved in a third solvent and a second acid-binding agent is added. Iodine ethane is added dropwise at 10–40 °C, and the reaction is carried out at 20–40 °C for 4–8 h. After the reaction is completed, the third solvent is removed to obtain crude photoinitiator 369.

[0017] As an improvement to the above technical solution, in step (1), chlorobenzene and morpholine are dissolved in the first solvent, and the first acid-binding agent and the first catalyst are added. The mixture is refluxed at 60-90°C for 8-16 hours. After the reaction is completed, the temperature is lowered to 10-40°C, 8-12 times the weight of water of chlorobenzene is added, and the mixture is extracted with the second solvent. The resulting organic phase is used as an intermediate system.

[0018] In step (2), phenylalanine and the second catalyst are mixed evenly at -20℃ to 0℃, and the intermediate system is added dropwise. After the addition is complete, the reaction is carried out at -20℃ to 0℃ for 2 to 4 hours. The reaction is quenched with water at 8 to 12 times the weight of the chlorobenzene, and the second solvent is separated to obtain compound I; and / or

[0019] In step (3), compound I is mixed with formic acid, and a 20-60 wt% formaldehyde aqueous solution is added dropwise at 10-40°C. After the addition is complete, the mixture is refluxed at 80-100°C for 2-4 hours. After the reaction is complete, the temperature is lowered to 10-40°C, and water is added to the organic phase. The resulting organic phase is separated from water to obtain compound II; and / or

[0020] In step (4), compound II is mixed with a third solvent of 2 to 6 times its weight, a second acid-binding agent is added at 10 to 40°C, and iodoethane is added dropwise. After the addition is complete, the reaction is carried out at 20 to 40°C for 4 to 6 hours. After the reaction is completed, the first extractant is added for extraction. The first extractant is recovered from the organic phase obtained by extraction, and the crude photoinitiator 369 is obtained.

[0021] As an improvement to the above technical solution, the first solvent is selected from one or more of DMF, DMSO, NMP, and DMA; the weight ratio of the first solvent to the chlorobenzene is 2 to 5:1; and / or

[0022] The first catalyst is selected from one or more of copper salt catalysts, nickel salt catalysts, and palladium salt catalysts; the weight ratio of the first catalyst to the chlorobenzene is 0.3 to 1:100; and / or

[0023] The first acid-binding agent is selected from one or more of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium phosphate, and sodium hydroxide; the molar ratio of the first acid-binding agent to the chlorobenzene is 1.2 to 2:1; and / or

[0024] The molar ratio of the morpholine to the chlorobenzene is 2-5:1-1.2.

[0025] As an improvement to the above technical solution, the second solvent is selected from one or more of dichloromethane, dichloroethane, and n-heptane; the weight ratio of the second solvent to the chlorobenzene is 8-12:1; and / or

[0026] The second catalyst is selected from one or more of aluminum chloride, zinc chloride, and ferric chloride; the molar ratio of the second catalyst to the chlorobenzene is 1 to 2:1; and / or

[0027] The molar ratio of phenylalanine to chlorobenzene is 1 to 2:1.

[0028] As an improvement to the above technical solution, the molar ratio of compound I to formic acid is 1:1.2-5; and / or

[0029] The molar ratio of compound I to formaldehyde is 1:2 to 5.

[0030] As an improvement to the above technical solution, the third solvent is selected from one or more of DMF, THF, DCM, and DCE, and the weight ratio of the third solvent to compound II is 2 to 6:1; and / or

[0031] The second acid-binding agent is selected from one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, and sodium bicarbonate, and the molar ratio of the second acid-binding agent to compound II is 1.5 to 5:1; and / or

[0032] The molar ratio of iodoethane to compound II is 1 to 3:1.

[0033] As an improvement to the above technical solution, the first solvent is DMF; the weight ratio of the first solvent to the chlorobenzene is 2.5–3.3:1; and / or

[0034] The first catalyst is a copper salt catalyst, wherein the copper salt is cuprous chloride, copper acetate, copper chloride, copper bromide, cuprous bromide, cuprous iodide, or quinoline copper; the weight ratio of the first catalyst to the chlorobenzene is 0.4–0.6:100; and / or

[0035] The first acid-binding agent is potassium carbonate; the molar ratio of the first acid-binding agent to the chlorobenzene is 1.2–1.4:1; and / or

[0036] The molar ratio of the morpholine to the chlorobenzene is 1.9–2.5:1; and / or

[0037] The second solvent is dichloroethane; the weight ratio of the second solvent to the chlorobenzene is 9–10.5:1; and / or

[0038] The second catalyst is aluminum chloride; the molar ratio of the second catalyst to the chlorobenzene is 1.1–1.5:1; and / or

[0039] The molar ratio of phenylalanine to chlorobenzene is 1.1 to 1.3:1.

[0040] As an improvement to the above technical solution, the molar ratio of compound I to formic acid is 1:1.8 to 2.5; and / or

[0041] The molar ratio of compound I to formaldehyde is 1:2 to 2.5; and / or

[0042] The weight ratio of water used for separation to compound I is 1 to 3:1; and / or

[0043] The third solvent is selected as DMF, and the weight ratio of the third solvent to compound II is 3 to 5:1; and / or

[0044] The second acid-binding agent is selected from sodium hydroxide and sodium carbonate, wherein the molar ratio of sodium hydroxide to compound II is 1 to 1.5:1, and the molar ratio of sodium carbonate to compound II is 0.3 to 0.8:1; and / or

[0045] The molar ratio of iodoethane to compound II is 1 to 1.5:1; and / or

[0046] The first extractant is selected from dichloromethane or dichloroethane, and the weight ratio of the first extractant to compound II is 3 to 6:1.

[0047] As an improvement to the above technical solution, a purification step is also included;

[0048] The purification step includes: dissolving the crude photoinitiator in a fourth solvent at 60-80°C, then crystallizing it at -10-25°C for 1-3 hours, and separating the solid and liquid components.

[0049] The fourth solvent is selected from one or more of methanol, ethanol, isopropanol, tert-butanol, butanone, and methyl isobutyl ketone.

[0050] Implementing this invention has the following beneficial effects:

[0051] In the preparation method of photoinitiator 369 of the present invention, N-phenylmorpholine is synthesized from chlorobenzene and morpholine as starting materials, and then reacted with phenylalanine via a Friedel-Crafts reaction to synthesize compound I. Compound I undergoes aminomethylation reaction with formic acid and formaldehyde to synthesize compound II. Finally, compound II reacts with iodoethane to obtain the product. The synthesis method of the present invention has a simple process route, high yield, and does not use fluorobenzene or bromine, has low equipment requirements, and is easy to industrialize. Attached Figure Description

[0052] Figure 1 This is a flowchart of a method for preparing photoinitiator 369 in one embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0054] This invention provides a method for preparing photoinitiator 369, which includes the following steps:

[0055] S1: Chlorobenzene and morpholine undergo Ullmann CN coupling in the presence of a first catalyst to give N-phenylmorpholine;

[0056] The chemical reactions that occur in this step are as follows:

[0057]

[0058] In one embodiment, chlorobenzene and morpholine are dissolved in a first solvent, and a first acid-binding agent and a first catalyst are added. The mixture is refluxed at 60–90°C for 8–16 hours. After the reaction is completed, the first solvent is separated to obtain N-phenylmorpholine.

[0059] The molar ratio of morpholine to chlorobenzene is 2–5:1–1.2, with exemplary ratios of 2:1.2, 2.3:1, 3.5:1.1, 4.7:1.2, 4.3:1.05, or 4:1.1, but not limited thereto. A preferred ratio is 1.9–2.5:1.

[0060] The first solvent is selected from one or more of DMF, DMSO, NMP, and DMA, but is not limited thereto; preferably, the first solvent is selected from DMF and / or DMA, and more preferably, the first solvent is selected from DMF.

[0061] The weight ratio of the first solvent to chlorobenzene is 2 to 5:1, with exemplary ratios being 2.5:1, 2.9:1, 3.3:1, 3.5:1, or 3.8:1, but not limited thereto. A ratio of 2.5 to 3.3:1 is preferred.

[0062] The first acid-binding agent is selected from one or more of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium phosphate, and sodium hydroxide, but is not limited thereto. Preferably, the first acid-binding agent is sodium carbonate or potassium carbonate, and more preferably, the first acid-binding agent is potassium carbonate.

[0063] The molar ratio of the first acid-binding agent to chlorobenzene is 1.2 to 2:1; exemplary ratios are 1.3:1, 1.5:1, 1.7:1, or 1.9:1, but are not limited thereto. Preferably, the molar ratio of the first acid-binding agent to chlorobenzene is 1.2 to 1.4:1.

[0064] The first catalyst is selected from one or more of copper salt catalysts, nickel salt catalysts, and palladium salt catalysts. For example, the copper salt in the copper salt catalyst is cuprous chloride, copper acetate, copper chloride, copper bromide, cuprous bromide, cuprous iodide, or quinoline copper, but is not limited thereto. The nickel salt catalyst can be nickel acetate or activated carbon-supported metallic nickel, and the palladium salt in the palladium salt catalyst is palladium acetate or tetrakis(triphenylphosphine)palladium, but is not limited thereto. Preferably, the first catalyst is a copper salt catalyst. More preferably, the first catalyst is a cuprous chloride catalyst.

[0065] The weight ratio of the first catalyst to chlorobenzene is 0.3 to 1:100, exemplarily 0.4:100, 0.6:100, 0.7:100, or 0.8:100, but not limited thereto. Preferably, the weight ratio of the first catalyst to chlorobenzene is 0.4 to 0.6:100.

[0066] Specifically, after the reaction is complete, N-phenylmorpholine can be obtained by extraction with a polar solvent and then drying to remove the first solvent, but it is not limited to this.

[0067] Preferably, in one embodiment, after the reaction is complete, water and a second solvent are added sequentially, and the organic phase is extracted, thereby achieving the separation of the reaction product (N-phenylmorpholine) from the first solvent. Specifically, the amount of water added is 8 to 12 times the weight of chlorobenzene, exemplarily 8.5, 8.7, 9.4, 10.4, 11.5, or 11.8 times, but not limited thereto. Preferably, the amount of water added is 9 to 11 times the weight of chlorobenzene. The amount of the second solvent added is 8 to 12 times the weight of chlorobenzene, exemplarily 8.5, 8.7, 9.4, 10.4, 11.5, or 11.8 times, but not limited thereto. Preferably, the amount of the second solvent added is 9 to 10.5 times the weight of chlorobenzene.

[0068] The organic phase obtained by extraction with the second solvent can be used for subsequent reactions after separating the second solvent, or the subsequent reactions can be carried out directly with the organic phase containing the second solvent (intermediate system). More preferably, step S1 includes: dissolving chlorobenzene and morpholine in the first solvent, adding the first acid-binding agent and the first catalyst, refluxing at 60-90°C for 8-16 hours, cooling to 10-40°C after the reaction, adding 8-12 times the weight of water of chlorobenzene, and extracting with the second solvent, with the resulting organic phase serving as the intermediate system.

[0069] S2: N-phenylmorpholine reacts with phenylalanine via a Friedel-Crafts reaction to prepare compound I;

[0070] The chemical reactions that occur in this step are as follows:

[0071]

[0072] In one embodiment, step S2 includes: dissolving N-phenylmorpholine and phenylalanine in a second solvent, adding a second catalyst, reacting at -20 to 0°C for 2 to 8 hours, separating the second solvent, and obtaining compound I;

[0073] The molar ratio of phenylalanine to chlorobenzene is 1 to 2:1, with exemplary ratios of 1.2:1, 1.4:1, 1.6:1, or 1.8:1, but not limited thereto. A preferred ratio is 1.1 to 1.3:1.

[0074] The second solvent is selected from one or more of dichloromethane, dichloroethane, and n-heptane, but is not limited thereto. Preferably, the second solvent is dichloromethane or dichloroethane, and more preferably dichloroethane.

[0075] The weight ratio of the second solvent to chlorobenzene is 8 to 12:1, with exemplary ratios of 8.5:1, 9.3:1, 10.7:1, 11.4:1, or 11.7:1, but not limited thereto. Preferably, it is 9 to 10.5:1.

[0076] The second catalyst may be selected from one or more of aluminum chloride, zinc chloride, and ferric chloride, but is not limited to these. Preferably, aluminum chloride is selected.

[0077] The molar ratio of the second catalyst to chlorobenzene is 1 to 2:1, exemplarily 1.2:1, 1.4:1, 1.6:1 or 1.8:1, but not limited thereto. Preferably, it is 1.1 to 1.5:1.

[0078] Specifically, in this step, N-phenylmorpholine and phenylalanine can be dissolved in a second solvent, or the intermediate system obtained in step S1 can be used directly for the reaction. Preferably, the intermediate system obtained in step S1 is added to phenylalanine for the reaction. More preferably, adding the intermediate system obtained in step S1 dropwise to phenylalanine can promote the conversion efficiency of the reaction. The present invention does not have any particular limitation on the dropping rate.

[0079] Specifically, after the reaction is complete, water can be added directly to quench the reaction, and the second solvent can be removed by concentration or distillation after separation to obtain compound I. Alternatively, after the reaction is complete, the reaction product can be added dropwise to water, stirred, and the second solvent can be removed by concentration or distillation after separation to obtain compound I.

[0080] Preferably, in one embodiment, step S2 includes: mixing phenylalanine and the second catalyst uniformly at -20°C to 0°C, adding the intermediate system dropwise, reacting at -20°C to 0°C for 2 to 4 hours after the addition is complete, quenching the reaction with water at 8 to 12 times the weight of the chlorobenzene, separating the second solvent, and obtaining compound I.

[0081] S3: Compound I undergoes aminomethylation reaction with formic acid and formaldehyde to prepare compound II;

[0082] The chemical reactions that occur in this step are as follows:

[0083]

[0084] Specifically, in one embodiment, step S3 includes: mixing compound I with formic acid and a formaldehyde aqueous solution with a concentration of 20-60 wt%, and refluxing at 80-100°C for 2-5 hours to obtain compound II;

[0085] The molar ratio of compound I to formic acid is 1:1.2 to 5, with exemplary ratios of 1:1.5, 1:2, 1:2.5, 1:3, 1:4, or 1:4.5, but not limited thereto. A preferred ratio is 1:1.8 to 2.5.

[0086] The molar ratio of compound I to formaldehyde is 1:2 to 5, with exemplary ratios of 1:2.2, 1:2.8, 1:3.4, 1:3.6, 1:4.3, or 1:4.8, but not limited thereto. A preferred ratio is 1:2 to 2.5.

[0087] Formaldehyde is provided in the form of an aqueous solution, which can be added dropwise, but is not limited thereto. This invention does not impose any particular limitation on the dropping rate of the aqueous formaldehyde solution.

[0088] For example, the concentration of the formaldehyde aqueous solution is 25 wt%, 28 wt%, 35 wt%, 40 wt%, 47 wt%, 50 wt%, or 55 wt%, but is not limited thereto. Preferably, it is 25 wt% to 50 wt%, and more preferably, it is 30 wt% to 45 wt%.

[0089] Specifically, after the reaction is complete, water can be added directly, and the water in the organic phase can be separated after liquid-liquid separation to obtain compound II; or after the reaction is complete, the temperature can be lowered first, then water can be added, and the water in the organic phase can be separated after liquid-liquid separation to obtain compound II.

[0090] Preferably, in one embodiment, step S3 includes: mixing compound I with formic acid, adding a 20-60 wt% formaldehyde aqueous solution dropwise at 10-40°C, refluxing at 80-100°C for 2-4 hours after the addition is complete, cooling to 10-40°C, adding 1-3 times the weight of water of compound I, stirring for 10-30 minutes, allowing to stand and separate the organic phase, washing the organic phase with 1-3 times the weight of water of compound I, drying and concentrating to recover the water, thus obtaining compound II.

[0091] S4: Compound II reacts with iodoethane to give crude photoinitiator 369.

[0092] Specifically, the chemical reactions that occur in this step are as follows:

[0093]

[0094] Specifically, in one embodiment, step S4 includes: dissolving compound II in a third solvent, adding a second acid-binding agent, adding iodoethane dropwise at 10–40°C, reacting at 20–40°C for 4–8 hours, and removing the third solvent after the reaction is complete to obtain crude photoinitiator 369.

[0095] The third solvent is selected from one or more of DMF, THF, DCM, and DCE, but is not limited to these. Preferably, the third solvent is DMF.

[0096] The weight ratio of the third solvent to compound II is 2 to 6:1, exemplary ratios are 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or 5.5:1, but not limited thereto. Preferably it is 3 to 5:1.

[0097] The second acid-binding agent is selected from one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, and sodium bicarbonate, but is not limited thereto. Preferably, the second acid-binding agent is a mixture of sodium hydroxide and sodium carbonate, and the molar ratio of sodium hydroxide to sodium carbonate is 2 to 3:1.

[0098] The molar ratio of the second acid-binding agent to compound II is 1.5 to 5:1, exemplarily 1.8:1, 2.2:1, 3:1, 3.5:1 or 4.4:1, but not limited thereto. A ratio of 1.5 to 3:1 is preferred.

[0099] Preferably, in one embodiment of the present invention, the second acid-binding agent is selected from sodium hydroxide and sodium carbonate, wherein the molar ratio of sodium hydroxide to compound II is 1 to 1.5:1, and the molar ratio of sodium carbonate to compound II is 0.3 to 0.8:1.

[0100] The molar ratio of iodoethane to compound II is 1 to 3:1, with exemplary ratios being 1.5:1, 1.8:1, 2.2:1, 2.5:1, or 2.8:1. A preferred ratio is 1 to 1.5:1.

[0101] Specifically, after the reaction is complete, water can be added to the solution, and the organic phase can be separated to obtain the product. Alternatively, it can be extracted with a first extractant. Preferably, in one embodiment, step S4 includes: mixing compound II with 2 to 6 times its weight of a third solvent, adding a second acid-binding agent at 10 to 40°C, and adding iodoethane dropwise. After the addition is complete, the reaction is carried out at 20 to 40°C for 4 to 6 hours. After the reaction is complete, the first extractant is added for extraction, and the first extractant is recovered from the organic phase obtained by extraction to obtain crude photoinitiator 369.

[0102] The first extractant is selected from dichloromethane or dichloroethane, but is not limited to these. Dichloromethane is preferred. The weight ratio of the first extractant to compound II is 3 to 6:1, exemplarily 3.5:1, 4:1, 4.5:1, 5:1 or 5.5:1, but is not limited to these. 3 to 5:1 is preferred.

[0103] Preferably, in one embodiment of the present invention, after extraction, the organic phase is washed with 1 to 3 times the weight of compound II with water, and then the first extractant is concentrated and recovered to obtain crude photoinitiator 369.

[0104] Preferably, in one embodiment of the present invention, the preparation method further includes the following steps:

[0105] S5: The crude product obtained from purification step S4;

[0106] Specifically, purification can be carried out through processes such as recrystallization, but is not limited to these. Preferably, in one embodiment, the crude photoinitiator is dissolved in a fourth solvent at 60–80°C, and then crystallized at -10–25°C for 1–3 hours, followed by solid-liquid separation. The fourth solvent is selected from one or more of methanol, ethanol, isopropanol, tert-butanol, butanone, and methyl isobutyl ketone, but is not limited to these. The amount of the fourth solvent is 1–3 times the weight of the crude photoinitiator 369, but is not limited to this.

[0107] The present invention will be further described below with reference to specific embodiments:

[0108] Example 1

[0109] This embodiment provides a method for preparing photoinitiator 369, specifically including:

[0110] A thermometer was inserted into a 250ml three-necked flask. 20g of chlorobenzene was added to the reaction flask, followed by 80g of DMA, 41.5g of morpholine, 36.5g of potassium carbonate, and 0.16g of copper salt (CuCl2). The mixture was heated to 80℃ and refluxed for 10 hours. The reaction conversion rate was 97% as determined by liquid chromatography. The reaction was stopped and cooled to room temperature. The system was then added to 220g of water and extracted with 220g of dichloroethane. The organic phase was dried over 5g of anhydrous sodium sulfate to obtain the intermediate system.

[0111] 32.2 g of phenylalanine was added to a reaction flask, a thermometer was inserted, and the temperature was lowered to 0–-5 °C. While maintaining the temperature below 0 °C, 35.6 g of aluminum trichloride was added in batches. After stirring for 1 hour, the intermediate system obtained in the first step was added dropwise while maintaining the temperature below 0 °C. After the addition was complete, the reaction was maintained at the temperature for 3 hours. Liquid chromatography showed a purity of 98.3%. While maintaining the temperature below 40 °C, the system was slowly added dropwise to 240 g of water, stirred for 1 hour, separated, and the solvent was recovered by concentration, yielding 50.4 g of a light brown solid. The crude product yield was 91.3%, and the purity was 98.6%.

[0112] Add 50.4g of the product obtained in the previous step to a 250ml three-necked flask equipped with a thermometer, add 15.4g of formic acid, and then add 31g of 50% formaldehyde aqueous solution dropwise at room temperature. After the addition is complete, heat to 90℃ and reflux for 3 hours. Take a sample for liquid phase analysis, and the purity is 96%. Stop the reaction and cool to room temperature. Add 130g of water to the system and stir for 30 minutes. After standing, separate the liquid and organic phases. Wash the organic phase with 130g of water, dry and concentrate to recover the solvent, and obtain 51.6g of brown viscous liquid. Solidify at room temperature, with a purity of 96.2% and a crude product yield of 90.8%.

[0113] Add 51.6g of the product obtained in the previous step to a 500ml reaction flask equipped with a thermometer, add 265g of THF, add 10.6g of sodium hydroxide while stirring at room temperature, and add 35.6g of iodoethane dropwise. After the addition is complete, heat to 25℃ and react for 5h. Take a sample and test the purity of the liquid phase to 92.3%. Concentrate and recover the solvent, add 250g of dichloromethane for extraction, wash the organic phase with 100g of water, dry and concentrate to recover the solvent, and obtain 49.6g of dark brown liquid. Solidify at room temperature with a purity of 93.1% and a crude product yield of 88.8%.

[0114] 49.6g of crude 369 product was added to 51.1g of methanol, heated to 70℃ and refluxed for 1h, then cooled to -5℃ and stirred for 0.5h. The mixture was filtered to obtain bright yellow granular crystals, washed twice with 5g of cold methanol, and the product was vacuum dried at 60℃ to obtain 46.1g of bright yellow solid granules with a purity of 98.9% and a crystallization yield of 90.2%.

[0115] Example 2

[0116] This embodiment provides a method for preparing photoinitiator 369, specifically including:

[0117] A thermometer was inserted into a 250ml three-necked flask. 20g of chlorobenzene was added to the reaction flask, followed by 60g of DMF, 31g of morpholine, 31.9g of potassium carbonate, and 0.1g of copper salt (CuCl). The mixture was heated to 80℃ and refluxed, and the reaction was maintained at this temperature for 10 hours. The liquid phase analysis showed a reaction conversion rate of 97%. The reaction was stopped and the mixture was cooled to room temperature. The system was then added to 200g of water and extracted with 200g of dichloroethane. The organic phase was dried with 5g of anhydrous sodium sulfate to obtain the intermediate system.

[0118] 35.2 g of phenylalanine was added to a reaction flask, a thermometer was inserted, and the temperature was lowered to 0–-5 °C. While maintaining the temperature below 0 °C, 28.4 g of aluminum trichloride was added in batches. After stirring for 1 hour, the intermediate system obtained in the first step was added dropwise while maintaining the temperature below 0 °C. After the addition was complete, the reaction was maintained at the temperature for 3 hours. Liquid chromatography analysis showed a purity of 97.9%. While maintaining the temperature below 40 °C, the system was slowly added dropwise to 200 g of water, stirred for 1 hour, separated, and the solvent was recovered by concentration, yielding 52.1 g of a light brown solid. The crude product yield was 94.4%, and the purity was 98.2%.

[0119] Add 52.1g of the product obtained in the previous step to a 250ml three-necked flask equipped with a thermometer, add 15.4g of formic acid, and then add 25.2g of 40% formaldehyde aqueous solution dropwise at room temperature. After the addition is complete, heat to 90℃ and reflux for 3 hours. Take a sample for liquid phase analysis, and the purity is 95.8%. Stop the reaction and cool to room temperature. Add 100g of water to the system and stir for 20 minutes. After standing, separate the liquid and organic phases. Wash the organic phase with 100g of water, dry and concentrate to recover the solvent, and obtain 52.9g of brown viscous liquid. Solidify at room temperature, with a purity of 96.5% and a crude product yield of 93.2%.

[0120] Add 52.9g of the product obtained in the previous step to a 500ml reaction flask equipped with a thermometer, add 212g of DMF, and add 7.5g of sodium hydroxide and 8.3g of sodium carbonate while stirring at room temperature. Add 29.3g of iodoethane dropwise, and after the addition is complete, heat to 25℃ and react for 5h. Take a sample and test the purity of the liquid phase to be 93.4%. Concentrate and recover the solvent, add 200g of dichloromethane for extraction, wash the organic phase with 100g of water, dry and concentrate to recover the solvent, and obtain 51.1g of dark brown liquid. Solidify at room temperature to obtain crude product 369 with a purity of 93.9% and a crude product yield of 89.1%.

[0121] 51.1g of crude 369 product was added to 51.1g of methanol, heated to 70℃ and refluxed for 1h, then cooled to -5℃ and stirred for 0.5h. The mixture was filtered to obtain bright yellow granular crystals. The crystals were washed twice with 5g of cold methanol. The product was then vacuum dried at 60℃ to obtain 47.2g of bright yellow solid granules with a purity of 99.2% and a crystallization yield of 92.4%.

[0122] Example 3

[0123] This embodiment provides a method for preparing photoinitiator 369, specifically including:

[0124] 1 kg of chlorobenzene, 3 kg of DMF, 1.55 kg of morpholine, 1.59 kg of potassium carbonate, and 5 g of copper salt (CuCl) were added to a 25 L reactor. The mixture was heated to 80 °C and refluxed for 13 h. The reaction conversion rate was 97.9% as determined by liquid phase analysis. The reaction was stopped and the mixture was cooled to room temperature. The system was then added to 10 kg of water and extracted with 10 kg of dichloroethane. The organic phase obtained from the extraction was dried with 150 g of anhydrous sodium sulfate to obtain the intermediate system.

[0125] 1.76 kg of phenylalanine was added to a reactor, and the temperature was lowered to 0–-5 °C. While maintaining the temperature below 0 °C, 1.42 kg of aluminum trichloride was added in batches. After stirring for 1 hour, the intermediate system obtained in the previous step was added dropwise while maintaining the temperature below 0 °C. After the addition was complete, the reaction was maintained at this temperature for 5 hours. Liquid chromatography analysis showed a purity of 97.7%. While maintaining the temperature below 40 °C, the system was slowly added dropwise to 10 kg of water, stirred for 1 hour, separated, and the solvent was recovered by concentration, yielding 2.59 kg of a light brown solid. The crude product yield was 93.9%, and the purity was 98.3%.

[0126] 2.59 kg of the product obtained in the previous step was added to a 25 L reactor. 768 g of formic acid was added, and then 1.25 kg of 40% formaldehyde aqueous solution was added dropwise at room temperature. After the addition was complete, the temperature was raised to 90 °C and refluxed for 4.5 h. A sample of the liquid phase was taken for analysis, and the purity was 95.1%. The reaction was stopped and cooled to room temperature. 5 kg of water was added to the system and stirred for 30 min. After standing, the liquid was separated, and the organic phase was washed with 5 kg of water. The organic phase was dried, concentrated, and the solvent was recovered to obtain 2.62 kg of brown viscous liquid. The liquid solidified at room temperature, and the purity was 96.1%. The crude product yield was 92.8%.

[0127] 2.62 kg of the product obtained in the previous step was added to a 50 L reactor, along with 10.5 kg of DMF. 371.8 g of sodium hydroxide and 410.5 g of sodium carbonate were added under stirring at room temperature, followed by dropwise addition of 1.45 kg of iodoethane. After the addition was complete, the temperature was raised to 25 °C and reacted for 7 h. A liquid phase sample was taken, and the purity was determined to be 93.9%. The solvent was concentrated and recovered. 10 kg of dichloromethane was added for extraction, and the organic phase was washed with 5 kg of water. The mixture was dried, concentrated, and the solvent recovered, yielding 2.58 kg of a dark brown liquid. This liquid was cured at room temperature to obtain crude product 369, with a purity of 94.6% and a crude product yield of 90.9%.

[0128] 2.58 kg of crude 369 product was added to 2.58 kg of methanol, heated to 70 °C and refluxed for 1 h, then cooled to -5 °C and stirred for 0.5 h. The mixture was then filtered to obtain bright yellow granular crystals. The crystals were washed twice with 150 g of cold methanol. The product was then vacuum dried at 60 °C to obtain 2.41 kg of bright yellow solid granules with a purity of 99.1% and a crystallization yield of 93.3%.

[0129] The above description is a preferred embodiment of the invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A method for preparing photoinitiator 369, characterized in that, Includes the following steps: (1) Chlorobenzene and morpholine are dissolved in a first solvent, and a first acid-binding agent and a first catalyst are added. The mixture is refluxed at 60-90°C for 8-16 hours. After the reaction is completed, the first solvent is separated to obtain N-phenylmorpholine. The first solvent is selected from one or more of DMF, DMSO, NMP, and DMA. The weight ratio of the first solvent to the chlorobenzene is 2-5:

1. The first catalyst is selected from one or more of copper salt catalyst, nickel salt catalyst, and palladium salt catalyst. The weight ratio of the first catalyst to the chlorobenzene is 0.3-1:

100. The first acid-binding agent is selected from one or more of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium phosphate, and sodium hydroxide. The molar ratio of the first acid-binding agent to the chlorobenzene is 1.2-2:

1. The molar ratio of the morpholine to the chlorobenzene is 2-5:1-1.

2. (2) N-phenylmorpholine and phenylalanine are dissolved in a second solvent and a second catalyst is added. The mixture is reacted at -20 to 0°C for 2 to 8 hours. The second solvent is then separated to obtain compound I. The second solvent is selected from one or more of dichloromethane, dichloroethane, and n-heptane. The weight ratio of the second solvent to the chlorobenzene is 8 to 12:

1. The second catalyst is selected from one or more of aluminum chloride, zinc chloride, and ferric chloride. The molar ratio of the second catalyst to the chlorobenzene is 1 to 2:

1. The molar ratio of phenylalanine to the chlorobenzene is 1 to 2:

1. (3) Compound I is mixed with formic acid and a 20-60 wt% aqueous formaldehyde solution and refluxed at 80-100℃ for 2-5 h to obtain compound II; wherein the molar ratio of compound I to formic acid is 1:1.2-5; and the molar ratio of compound I to formaldehyde is 1:2-5. (4) Dissolve compound II in a third solvent and add a second acid-binding agent. Add iodoethane dropwise at 10-40°C and react at 20-40°C for 4-8 hours. After the reaction is complete, remove the third solvent to obtain crude photoinitiator 369. The third solvent is selected from one or more of DMF, THF, DCM, and DCE, and the weight ratio of the third solvent to compound II is 2-6:

1. The second acid-binding agent is selected from one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, and sodium bicarbonate, and the molar ratio of the second acid-binding agent to compound II is 1.5-5:

1. The molar ratio of iodoethane to compound II is 1-3:

1.

2. The method for preparing photoinitiator 369 as described in claim 1, characterized in that, In step (1), chlorobenzene and morpholine are dissolved in the first solvent, and the first acid-binding agent and the first catalyst are added. The mixture is refluxed at 60~90℃ for 8~16h. After the reaction is completed, the temperature is lowered to 10~40℃, 8~12 times the weight of water of chlorobenzene is added, and the mixture is extracted with the second solvent. The resulting organic phase is used as an intermediate system. In step (2), phenylalanine and the second catalyst are mixed evenly at -20℃ to 0℃, and the intermediate system is added dropwise. After the addition is complete, the reaction is carried out at -20℃ to 0℃ for 2 to 4 hours. The reaction is quenched with water at 8 to 12 times the weight of the chlorobenzene, and the second solvent is separated to obtain compound I; and / or In step (3), compound I is mixed with formic acid, and a 20-60 wt% formaldehyde aqueous solution is added dropwise at 10-40°C. After the addition is complete, the mixture is refluxed at 80-100°C for 2-4 hours. After the reaction is complete, the temperature is lowered to 10-40°C, and water is added to the organic phase. The resulting organic phase is separated from the water to obtain compound II; and / or In step (4), compound II is mixed with a third solvent of 2 to 6 times its weight, a second acid-binding agent is added at 10 to 40°C, and iodoethane is added dropwise. After the addition is complete, the reaction is carried out at 20 to 40°C for 4 to 6 hours. After the reaction is completed, the first extractant is added for extraction. The first extractant is recovered from the organic phase obtained by extraction, and the crude photoinitiator 369 is obtained.

3. The method for preparing photoinitiator 369 as described in claim 1 or 2, characterized in that, The first solvent is DMF; the weight ratio of the first solvent to the chlorobenzene is 2.5~3.3:1; and / or The first catalyst is a copper salt catalyst, wherein the copper salt is cuprous chloride, copper acetate, copper chloride, copper bromide, cuprous bromide, cuprous iodide, or quinoline copper; the weight ratio of the first catalyst to the chlorobenzene is 0.4~0.6:100; and / or The first acid-binding agent is potassium carbonate; the molar ratio of the first acid-binding agent to the chlorobenzene is 1.2~1.4:1; and / or The molar ratio of morpholine to chlorobenzene is 1.9~2.5:

1.

4. The method for preparing photoinitiator 369 as described in claim 1 or 2, characterized in that, The second solvent is dichloroethane; the weight ratio of the second solvent to the chlorobenzene is 9~10.5:1; and / or The second catalyst is aluminum chloride; the molar ratio of the second catalyst to the chlorobenzene is 1.1~1.5:1; and / or The molar ratio of phenylalanine to chlorobenzene is 1.1 to 1.3:

1.

5. The method for preparing photoinitiator 369 as described in claim 1 or 2, characterized in that, The molar ratio of compound I to formic acid is 1:1.8~2.5; and / or The molar ratio of compound I to formaldehyde is 1:2 to 2.

5.

6. The method for preparing photoinitiator 369 as described in claim 1, characterized in that, The third solvent is DMF, and the weight ratio of the third solvent to compound II is 3-5:1; and / or The second acid-binding agent is selected from sodium hydroxide and sodium carbonate, wherein the molar ratio of sodium hydroxide to compound II is 1~1.5:1, and the molar ratio of sodium carbonate to compound II is 0.3~0.8:1; and / or The molar ratio of iodoethane to compound II is 1 to 1.5:

1.

7. The method for preparing photoinitiator 369 as described in claim 2, characterized in that, The weight ratio of water used for separation to compound I is 1 to 3:

1.

8. The method for preparing photoinitiator 369 as described in claim 2, characterized in that, The first extractant is selected from dichloromethane or dichloroethane, and the weight ratio of the first extractant to compound II is 3~6:

1.

9. The method for preparing photoinitiator 369 as described in claim 1 or 2, characterized in that, It also includes a purification step; The purification step includes: dissolving the crude photoinitiator in a fourth solvent at 60~80℃, then crystallizing it at -10~25℃ for 1~3h, and separating the solid and liquid components; The fourth solvent is selected from one or more of methanol, ethanol, isopropanol, tert-butanol, butanone, and methyl isobutyl ketone.

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