Preparation method of oxime ester photoinitiator OXE-02

Abstract

The application belongs to the technical field of photoinitiator preparation, and particularly relates to a preparation method of an oxime ester photoinitiator OXE-02, which comprises the following steps: (1) a compound of formula I-1 is first reacted with methyl o-toluic acid methyl ester, a reaction product is further reacted with methyl acetate, and a compound of formula I-2 is obtained; (2) the compound of formula I-2 is first reacted with hydroxylamine hydrochloride, a reaction product is further reacted with methyl acetate, and the photoinitiator OXE-02 shown in formula I-3 is obtained. The preparation method has simple process steps, is convenient to separate and purify, the yield of the prepared photoinitiator OXE-02 can reach more than 80%, the purity can reach more than 99.0%, and meanwhile, the preparation method is low in cost and environment-friendly.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoinitiator preparation, and particularly relates to a preparation method of an oxime ester photoinitiator OXE-02. BACKGROUND

[0002] OXE-02 belongs to the oxime ester photoinitiator. Since a carbazole group is introduced into the oxime ester compound, OXE-02 has a large conjugated system and strong intramolecular electron transfer characteristics, thereby greatly improving the stability and photosensitivity, and can efficiently initiate the polymerization of acrylate double bonds in the resist formula. OXE-02 has the advantages of fast initiation speed, strong resistance to oxygen inhibition, good deep curing, and can be used for colored systems. It has high transparency to the color of the photosensitive material, less photoresist residue, good stability, and is mainly applied in photoresist. The most common method for synthesizing OXE-02 is a three-step synthesis reaction. In 2009, Song Guoqiang et al. disclosed a synthesis method of OXE-02, and the total yield of the three steps was 62.4%, and the specific reaction is as follows:

[0003] For convenience of description, 3-acetyl-6-o-methylbenzoyl-N-ethyl carbazole is referred to as diketone compound; 1-(6-o-methylbenzoyl-N-ethyl carbazole-3-yl)-ethanone oxime is referred to as ketone oxime compound; and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone 1-(O-acetyloxime) is referred to as OXE-02.

[0004] (1) N-ethyl carbazole is used as a raw material, and a diketone compound is obtained by a Friedel-Crafts acylation reaction with two acyl chloride reagents, wherein the amounts of aluminum trichloride in the two acylation reactions are 1.1 eq and 1.1 eq, respectively. The synthesis route is shown in the following equation:

[0005]

[0006] (2) Then, a ketone oxime compound is obtained by condensation through an oximation reaction with hydroxylamine hydrochloride in the second step. The synthesis route is shown in the following equation:

[0007]

[0008] (3) In the third step, esterification is performed between the oxime and an acetylation reagent, and the photoinitiator OXE-02 is obtained after purification. The synthesis route is shown in the following equation:

[0009]

[0010] The prior art can synthesize the photoinitiator OXE-02, but the reaction still has some limitations: (1) the steps are too long, tedious and lengthy, the reagents such as aluminum chloride and acetyl chloride are highly corrosive, a large amount of hydrochloric acid is generated in the first step reaction, and the environment is polluted; (2) the amount of wastewater is too large, a large amount of wastewater is generated in three steps; (3) the total yield of three steps is 62.4%, the yield is low, and the economic benefit is not strong. Therefore, it is urgent to develop a process method for efficiently and more greenly synthesizing the photoinitiator OXE-02. SUMMARY

[0011] In view of the problems of large amount of material, large amount of wastewater, low product yield and the like in the existing OXE-02 preparation technology, the application provides a novel preparation method of the oxime ester photoinitiator OXE-02. The method synthesizes 3,6-dibromo-9-ethylcarbazole as a starting material through a two-step method, and the photoinitiator OXE-02 with a purity of more than 99.0% can be obtained by simply stirring and purifying the obtained crude product. Meanwhile, the process steps are simple, safe and environmentally friendly, and are more suitable for industrial production.

[0012] Specifically, the application provides the following technical scheme:

[0013] A preparation method of the oxime ester photoinitiator OXE-02, and a synthesis route is as follows:

[0014]

[0015]

[0016] The method comprises the following steps:

[0017] (1) The compound of formula I-1 is first reacted with methyl o-toluate, and the reaction product is further reacted with methyl acetate to obtain the compound of formula I-2.

[0018] (2) The compound of formula I-2 is first reacted with hydroxylamine hydrochloride, and the reaction product is further reacted with methyl acetate to obtain the photoinitiator OXE-02 shown in formula I-3.

[0019] As preferred, the step (1) is specifically:

[0020] The compound of formula I-1, zinc powder and an organic solvent A are added into a reactor, methyl o-toluate is added dropwise, after the dropwise addition is completed, the reaction is continuously stirred until the raw material is completely reacted, then methyl acetate is added dropwise, after the dropwise addition is completed, the reaction is continuously stirred until the raw material is completely reacted; water is added to the reaction liquid, after stirring for a period of time, the organic phase is collected and the solvent is removed to obtain the compound of formula I-2.

[0021] Further preferably, in step (1), the molar ratio of the compound of formula I-1, zinc powder, methyl o-toluate, methyl acetate is 1: (1.5-1.8): (1.0-1.1): (1.0-1.1).

[0022] Further preferably, in step (1), the organic solvent A is at least one of toluene, xylene, chlorobenzene, more preferably toluene.

[0023] Further preferably, in step (1), the volume ratio of the compound of formula I-1 and the organic solvent A is 1: (5-10).

[0024] Further preferably, in step (1), the reaction temperature is 70-100°C.

[0025] Further preferably, in step (1), the time for dropping methyl o-toluate is 3-5 hours; the time for dropping methyl acetate is 0.5-2 hours.

[0026] As preferred, the step (2) is specifically:

[0027] The compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate and mixed solvent B are added to a reactor, heated to reflux reaction until the raw material reaction is complete, then methyl acetate and concentrated sulfuric acid are added, and esterification reaction for a period of time; the reaction liquid is separated, the organic phase is collected and the solvent is removed, then added to the organic solvent C and stirred for a period of time, filtered, and the filter cake is dried to obtain the photoinitiator OXE-02 shown in formula I-3.

[0028] Further preferably, in step (2), the molar ratio of the compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate, methyl acetate, concentrated sulfuric acid is 1: (1.0-1.1):

[0029] (1.0-1.1): (1.1-1.2): (0.3-0.7).

[0030] Further preferably, in step (2), the mixed solvent B is at least one of dichloroethane, chloroform, trichloroethane mixed with water, wherein the volume fraction of water is 2-20%, and water is added to better dissolve hydroxylamine hydrochloride;

[0031] Further preferably, in step (2), the volume ratio of the compound of formula I-2 and the mixed solvent B is 1: (9-12).

[0032] Further preferably, in step (2), the reaction temperature is 50-80°C.

[0033] Further preferably, in step (2), the esterification reaction time is 12-36 hours.

[0034] Further preferably, in step (2), the organic solvent C is at least one of diethyl ether, propylene glycol, and isopropyl alcohol; more preferably, the organic solvent C is propylene glycol.

[0035] Further, the volume ratio of the compound of formula I-2 and the organic solvent C is 1:(5-7). The organic solvent C is added for impurity removal, and the use of the organic solvent C in the above composition and amount can more effectively remove unreacted raw materials and some colored high-molecular coupling by-products.

[0036] Further preferably, in step (2), the stirring time is 1-5 hours.

[0037] The beneficial effects achieved by the present application are as follows:

[0038] (1) The preparation method of the oxime ester photoinitiator OXE-02 provided by the present application first activates the bromine on the benzene ring by zinc, then connects the acetyl group through a nucleophilic substitution reaction, and finally generates oxime and ester through oximation and in-situ generation of acetic acid. The whole process is simple and very suitable for industrial production.

[0039] (2) The preparation method of the oxime ester photoinitiator OXE-02 provided by the present application avoids the use of toxic compounds such as aluminum trichloride and acetyl chloride, and reagents such as acetic anhydride that are not easy to buy, and has low cost, safety and environmental protection;

[0040] (3) The preparation method of the oxime ester photoinitiator OXE-02 provided by the present application has a yield of the prepared photoinitiator OXE-02 of 80% or more, and a purity of 99.0% or more;

[0041] (4) The preparation method of the oxime ester photoinitiator OXE-02 provided by the present application is convenient for subsequent separation, and only needs simple stirring and purification. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The nuclear magnetic resonance spectrum of the photoinitiator OXE-02 prepared in Example 1. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below, and the following embodiments are used to illustrate the present application but not to limit the scope of the present application. If the specific technology or condition is not specified in the embodiments, the technology or condition is carried out according to the technology or condition described in the literature in the art or according to the product instruction.

[0044] In the following embodiments, the compound 3,6-dibromo-9-ethylcarbazole of formula I-1 is derived from Anjieji.

[0045] Example 1

[0046] A method for preparing high-purity photoinitiator OXE-02, the steps are as follows:

[0047] (1) First step: 3,6-dibromo-9-ethylcarbazole (100.0 g, 0.28 mol), zinc powder (27.8 g, 0.42 mol) and toluene (500 mL) were added to a reaction bottle, heated to 70°C and kept, slowly added methyl o-toluic acid (42.5 g, 0.28 mol), 3 h after the dropwise addition was completed, the reaction was stirred, TLC detection of raw material disappeared, dropwise added methyl acetate (21.0 g, 0.28 mol), 0.2 h after the completion of the addition, TLC detection of raw material disappeared, reduced to room temperature, water was added to the reaction solution, stirred, separated, the organic phase was evaporated to dryness, 91.6 g of diketone compound was obtained, the yield was 91%.

[0048] (2) Second step: diketone compound (100.0 g, 0.28 mol), hydroxylamine hydrochloride (19.6 g, 0.28 mol), sodium bicarbonate (23.6 g, 0.28 mol) and chloroform / water (900 mL, 49:1) were added to a reaction bottle, heated to 50°C and reacted, TLC detection of raw material disappeared, added methyl acetate (22.9 g, 0.31 mol) and concentrated sulfuric acid (8.27 g, 0.08 mol), continued to react for 12 h, separated, the organic phase was evaporated to dryness, stirred with propylene glycol (500 mL) for 1 h, filtered, and dried to obtain 103.3 g of photoinitiator OXE-02, the yield was 89%, the purity was 99.1%, and the nuclear magnetic resonance spectrum was shown in Figure 1 .

[0049] The comprehensive yield of the method described in this example for synthesizing high-purity photoinitiator OXE-02 was 81%; the purity was tested by liquid chromatography, and it was found that the purity of OXE-02 synthesized by the method reached 99.1%.

[0050] Example 2

[0051] A method for preparing high-purity photoinitiator OXE-02, the steps are as follows:

[0052] (1) First step: 3,6-dibromo-9-ethylcarbazole (100.0 g, 0.28 mol), zinc powder (27.8 g, 0.42 mol) and toluene (500 mL) were added to a reaction bottle, heated to 70°C and kept, slowly added methyl o-toluic acid (42.5 g, 0.28 mol), 3 h after the dropwise addition was completed, the reaction was stirred, TLC detection of raw material disappeared, dropwise added methyl acetate (21.0 g, 0.28 mol), 0.2 h after the completion of the addition, TLC detection of raw material disappeared, reduced to room temperature, water was added to the reaction solution, stirred, separated, the organic phase was evaporated to dryness, 91.6 g of diketone compound was obtained, the yield was 91%.

[0053] (2) The second step: the diketone compound (100.0 g, 0.28 mol), hydroxylamine hydrochloride (20.5 g, 0.30 mol), sodium bicarbonate (20.5 g, 0.30 mol) and chloroform / water (900 mL, 49:1) were added into a reaction bottle, the reaction was heated at 60°C, after the disappearance of the raw material was detected by TLC, methyl acetate (22.9 g, 0.31 mol) and concentrated sulfuric acid (13.8 g, 0.14 mol) were added, and the reaction was continued for 24 h, the liquid was separated, the organic phase was evaporated to dryness, propylene glycol (1000 mL) was added and stirred for 2 h, filtered and dried to obtain 110.3 g of photoinitiator OXE-02 with a yield of 89% and a purity of 99.5%.

[0054] The overall yield of the method described in this example for synthesizing high-purity photoinitiator OXE-02 is 87%; the purity is tested by liquid chromatography, and it is found that the purity of OXE-02 synthesized by the method reaches 99.5%.

[0055] Example 3

[0056] A method for preparing a high-purity photoinitiator OXE-02, the steps are as follows:

[0057] (1) The first step: 3,6-dibromo-9-ethylcarbazole (100.0 g, 0.28 mol), zinc powder (33.3 g, 0.51 mol) and toluene (1000 mL) were added into a reaction bottle, heated to 100°C and kept, methyl o-toluate (46.8 g, 0.31 mol) was slowly added dropwise, after 5 h of dropwise addition, the reaction was stirred, after the disappearance of the raw material was detected by TLC, methyl acetate (23.1 g, 0.31 mol) was added dropwise, 2 h after the addition was completed, the temperature was lowered to room temperature, water was added to the reaction liquid, stirred, separated, and the organic phase was evaporated to dryness to obtain 90.6 g of diketone compound with a yield of 90%.

[0058] (2) The second step: the diketone compound (100.0 g, 0.28 mol), hydroxylamine hydrochloride (21.5 g, 0.31 mol), sodium bicarbonate (26.0 g, 0.31 mol) and chloroform / water (1200 mL, 49:1) were added into a reaction bottle, the reaction was heated at 80°C, after the disappearance of the raw material was detected by TLC, methyl acetate (25.0 g, 0.34 mol) and concentrated sulfuric acid (19.3 g, 0.20 mol) were added, and the reaction was continued for 36 h, the liquid was separated, the organic phase was evaporated to dryness, propylene glycol (700 mL) was added and stirred for 5 h, filtered and dried to obtain 104.5 g of photoinitiator OXE-02 with a yield of 90% and a purity of 99.2%.

[0059] The comprehensive yield of the high-purity photoinitiator OXE-02 synthesized by the method described in the embodiment is 81%; the purity is tested by liquid chromatography, and it is found that the purity of the OXE-02 synthesized by the method reaches 99.2%.

[0060] Although the present application has been described in detail with general description, specific embodiments and experiments above, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A method for preparing oxime ester-based photoinitiator OXE-02, characterized by, The synthetic route is as follows: The method comprises the following steps: (1) the compound of formula I-1, zinc powder and organic solvent A are added into a reactor, methyl o-toluate is added dropwise, after the dropwise addition is completed, the reaction is continued to stir until the raw material is completely reacted, then methyl acetate is added dropwise, after the dropwise addition is completed, the reaction is continued to stir until the raw material is completely reacted; water is added to the reaction solution, stirred for a period of time, then separated, the organic phase is collected and the solvent is removed, to obtain the compound of formula I-2; (2) the compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate and mixed solvent B are added into a reactor, heated to reflux until the raw material is completely reacted, then methyl acetate and concentrated sulfuric acid are added, and esterification is carried out for a period of time; the reaction solution is separated, the organic phase is collected and the solvent is removed, then added into organic solvent C and stirred for a period of time, filtered, and the filter cake is dried to obtain the photoinitiator OXE-02 shown in formula I-3.

2. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 1, characterized in that, In step (1), the molar ratio of the compound of formula I-1, zinc powder, methyl o-toluate, methyl acetate is 1: (1.5-1.8): (1.0-1.1): (1.0-1.1).

3. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 1, characterized in that, In step (1), the organic solvent A is at least one of toluene, xylene, chlorobenzene; And / or, the volume ratio of the compound of formula I-1 and the organic solvent A is 1: (5-10).

4. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 1, characterized in that, In step (2), the molar ratio of the compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate, methyl acetate, concentrated sulfuric acid H2SO4 is 1: (1.0-1.1): (1.0-1.1): (1.1-1.2): (0.3-0.7).

5. The method of claim 1, wherein the oxime ester photoinitiator OXE-02 is prepared by the process comprising: 5 reacting a compound of formula (II) with a compound of formula (III) in the presence of a base to form the oxime ester photoinitiator OXE-02. In step (2), the mixed solvent B is a mixed solvent of at least one of dichloroethane, chloroform, trichloroethane and water, wherein the volume fraction of water is 2-20%; And / or, the volume ratio of the compound of formula I-2 and the mixed solvent B is 1: (9-12).

6. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 1, characterized in that, In step (2), the organic solvent C is at least one of diethyl ether, propylene glycol, isopropyl alcohol; And / or, the volume ratio of the compound of formula I-2 and the organic solvent C is 1: (5-7).

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