Preparation method of oxime ester photoinitiator OXE-02

Abstract

The invention belongs to the technical field of preparation of photoinitiators, and particularly relates to a preparation method of an oxime ester photoinitiator OXE-02, which comprises the following steps: (1) firstly reacting a compound in a formula I-1 with methyl o-toluate, and further reacting a reaction product with methyl acetate to obtain a compound in a formula I-2; and (2) firstly reacting the compound shown in the formula I-2 with hydroxylamine hydrochloride, and further reacting the reaction product with methyl acetate to obtain the photoinitiator OXE-02 shown in the formula I-3. The preparation method is simple in process steps and convenient to separate and purify, the yield of the prepared photoinitiator OXE-02 can reach 80% or above, the purity can reach 99.0% or above, and meanwhile the preparation method is low in cost and environmentally friendly. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of photoinitiator preparation, and specifically relates to a method for preparing an oxime ester photoinitiator OXE-02. Background Art

[0002] OXE-02 belongs to the oxime ester photoinitiator. Due to the introduction of carbazole groups in the oxime ester compounds, OXE-02 has a large conjugated system and strong intramolecular electron transfer characteristics, which greatly improves 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 antioxidant inhibition ability, good deep curing, and can be used in colored systems. It has high transparency to the color of photosensitive materials, less photolithography residues, and good stability. It is mainly used in photoresists. The most common method for synthesizing OXE-02 is a three-step synthesis reaction. For example, in 2009, Song Guoqiang et al. disclosed the synthesis method of OXE-02, and the total yield of the three steps was 62.4%. The specific reaction is as follows:

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

[0004] (1) Using N-ethylcarbazole as a raw material, a diketone compound is obtained by Friedel-Crafts acylation 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 synthetic route is shown in the following equation:

[0005]

[0006] (2) Then, in the second step, oximation reaction is carried out with hydroxylamine hydrochloride to obtain a ketoxime compound. The synthesis route is shown in the following equation:

[0007]

[0008] (3) In the third step, the oxime undergoes an esterification reaction with an acetylating agent, and the photoinitiator OXE-02 is obtained after purification. The synthesis route is shown in the following equation:

[0009]

[0010] Although the above-mentioned prior art can synthesize the photoinitiator OXE-02, these reactions still have some limitations: (1) The steps are too long and cumbersome, and the required reagents such as aluminum chloride and acetyl chloride are highly corrosive. The first step of the reaction quenching produces a large amount of hydrochloric acid, which pollutes the environment; (2) The amount of wastewater is too large, and a large amount of wastewater is produced in all three steps; (3) The total yield of the three steps is 62.4%, which is low and the economic benefit is not strong. Therefore, it is urgent to develop a process method that can efficiently and greenly synthesize the photoinitiator OXE-02. Summary of the invention

[0011] In view of the problems existing in the existing OXE-02 preparation technology, such as large amount of materials used, large amount of wastewater, low product yield, etc., the present invention provides a new preparation method of oxime ester photoinitiator OXE-02. The method uses 3,6-dibromo-9-ethylcarbazole as a starting material and synthesizes it by a two-step method. The obtained crude product is purified by simple stirring to obtain a photoinitiator OXE-02 with a purity of more than 99.0%. At the same time, the process steps are simple, safe and environmentally friendly, and more suitable for industrial production.

[0012] Specifically, the present invention provides the following technical solutions:

[0013] A method for preparing an oxime ester photoinitiator OXE-02, the synthetic route is as follows:

[0014]

[0015]

[0016] The following steps are involved:

[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] Preferably, the step (1) is specifically:

[0020] Add the compound of formula I-1, zinc powder and organic solvent A into a reactor, add methyl o-toluate dropwise, and continue to stir the reaction until the raw material reacts completely after the addition is complete. Then add methyl acetate dropwise, and continue to stir the reaction until the raw material reacts completely after the addition is complete. Add water to the reaction solution, stir for a period of time, separate the liquids, collect the organic phase and remove the solvent 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 and 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 and chlorobenzene, more preferably toluene;

[0023] And / or, the volume ratio of the compound of formula I-1 to the organic solvent A is 1:(5-10).

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

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

[0026] Preferably, 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 and reacted until the raw materials react completely, and then methyl acetate and concentrated sulfuric acid are added to carry out esterification reaction for a period of time; the reaction solution is separated, the organic phase is collected and the solvent is removed, and 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 compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate, methyl acetate, H 2 SO 4 The molar ratio 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 a mixed solvent of at least one of dichloroethane, chloroform, and trichloroethane and water, wherein the volume fraction of water is 2-20%, and water is added to better dissolve hydroxylamine hydrochloride;

[0031] And / or, the volume ratio of the compound of formula I-2 to the mixed solvent B is 1:(9-12).

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

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

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

[0035] And / or, the volume ratio of the compound of formula I-2 to the organic solvent C is 1:(5-7). The organic solvent C is added for removing impurities. The organic solvent C with the above composition and amount can more effectively remove unreacted raw materials and some colored polymer coupling byproducts.

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

[0037] The beneficial effects achieved by the present invention are:

[0038] (1) The present invention provides a method for preparing an oxime ester photoinitiator OXE-02, which first activates the bromine on the benzene ring by zinc, then connects the acetyl group by a nucleophilic substitution reaction, and finally generates oxime and ester by oximation and in-situ generation of acetic acid. The entire 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 invention avoids the use of toxic compounds such as aluminum chloride, acetyl chloride and reagents that are not easy to buy such as acetic anhydride, and has low cost, safety and environmental protection;

[0040] (3) A method for preparing an oxime ester photoinitiator OXE-02 provided by the present invention, wherein the yield of the prepared photoinitiator OXE-02 can reach more than 80% and the purity can reach more than 99.0%;

[0041] (4) The present invention provides a method for preparing an oxime ester photoinitiator OXE-02, which is convenient for subsequent separation and only requires simple stirring and purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is the NMR 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 invention clearer, the technical scheme in the embodiments of the present invention is described clearly and completely below. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in the field or the product instructions are used.

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

[0045] Example 1

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

[0047] (1) The 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 flask, the temperature was raised to 70°C and kept warm, methyl o-toluate (42.5 g, 0.28 mol) was slowly added dropwise, and the reaction was stirred after 3 h of addition. After TLC detection of the disappearance of the raw material, methyl acetate (21.0 g, 0.28 mol) was added dropwise, and the addition was completed after 0.2 h. After TLC detection of the disappearance of the raw material, the temperature was cooled to room temperature, water was added to the reaction solution, stirred, separated, and the organic phase was evaporated to dryness to obtain 91.6 g of a diketone compound with a yield of 91%.

[0048] (2) Step 2: Add 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) into a reaction flask and heat to react at 50°C. After TLC detection shows that the raw material disappears, add methyl acetate (22.9 g, 0.31 mol) and concentrated sulfuric acid (8.27 g, 0.08 mol). Continue the reaction for 12 h, separate the liquids, evaporate the organic phase to dryness, add propylene glycol (500 mL), stir for 1 h, filter, and dry to obtain 103.3 g of photoinitiator OXE-02, with a yield of 89% and a purity of 99.1%. The NMR spectrum is shown in FIG. Figure 1 .

[0049] The comprehensive yield of the high-purity photoinitiator OXE-02 synthesized by the method described in this example is 81%. The purity is tested by liquid chromatography, and it is known that the purity of OXE-02 synthesized by the method reaches 99.1%.

[0050] Example 2

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

[0052] (1) The first step: 3,6-dibromo-9-ethylcarbazole (100.0 g, 0.28 mol), zinc powder (29.6 g, 0.45 mol) and toluene (700 mL) were added to a reaction flask, the temperature was raised to 80°C and kept warm, methyl o-toluate (43.4 g, 0.29 mol) was slowly added dropwise, and the reaction was stirred after 3 h of addition. After the raw material disappeared by TLC, methyl acetate (21.4 g, 0.29 mol) was added dropwise, and the addition was completed after 1 h. After the raw material disappeared by TLC, the temperature was cooled to room temperature, water was added to the reaction solution, stirred, separated, and the organic phase was evaporated to dryness to obtain 92.6 g of diketone compound with a yield of 92%.

[0053] (2) Step 2: Add 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) into a reaction flask and heat to 60°C for reaction. After TLC detection shows that the raw material disappears, add methyl acetate (22.9 g, 0.31 mol) and concentrated sulfuric acid (13.8 g, 0.14 mol) and continue the reaction for 24 h. Separate the liquids, evaporate the organic phase to dryness, add propylene glycol (1000 mL) and stir for 2 h, filter, and dry to obtain 110.3 g of photoinitiator OXE-02 with a yield of 89% and a purity of 99.5%.

[0054] The comprehensive yield of the high-purity photoinitiator OXE-02 synthesized by the method described in this example is 87%. The purity is tested by liquid chromatography, and it can be seen 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 to a reaction flask, the temperature was raised to 100°C and kept warm, methyl o-toluate (46.8 g, 0.31 mol) was slowly added dropwise, and the reaction was stirred after 5 h of addition. After the raw material disappeared by TLC, methyl acetate (23.1 g, 0.31 mol) was added dropwise, and the addition was completed after 2 h. After the raw material disappeared by TLC, the temperature was cooled to room temperature, water was added to the reaction solution, 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) Step 2: Add 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) into a reaction flask and heat to 80°C for reaction. After TLC detection shows that the raw material disappears, add methyl acetate (25.0 g, 0.34 mol) and concentrated sulfuric acid (19.3 g, 0.20 mol) and continue the reaction for 36 h. Separate the liquids, evaporate the organic phase to dryness, add propylene glycol (700 mL) and stir for 5 h, filter, and dry 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 this example is 81%. The purity is tested by liquid chromatography, and it can be seen that the purity of OXE-02 synthesized by the method reaches 99.2%.

[0060] Although the present invention has been described in detail above by general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for preparing an oxime ester photoinitiator OXE-02, characterized in that: The synthetic route is as follows: The following steps are involved: (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; (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.

2. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 1, characterized in that: The step (1) is specifically: Add the compound of formula I-1, zinc powder and organic solvent A into a reactor, add methyl o-toluate dropwise, and continue to stir the reaction until the raw material reacts completely after the addition is complete. Then add methyl acetate dropwise, and continue to stir the reaction until the raw material reacts completely after the addition is complete. Add water to the reaction solution, stir for a period of time, separate the liquids, collect the organic phase and remove the solvent to obtain the compound of formula I-2.

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

4. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 2, characterized in that: In step (1), the organic solvent A is at least one of toluene, xylene and chlorobenzene; And / or, the volume ratio of the compound of formula I-1 to the organic solvent A is 1:(5-10).

5. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 1 or 2, characterized in that: The step (2) is specifically: The compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate and mixed solvent B are added to a reactor, heated to reflux and reacted until the raw materials react completely, and then methyl acetate and concentrated sulfuric acid are added to carry out esterification reaction for a period of time; the reaction solution is separated, the organic phase is collected and the solvent is removed, and 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.

6. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 5, characterized in that: In step (2), the molar ratio of the compound of formula I-2, hydroxylamine hydrochloride, sodium bicarbonate, methyl acetate, and H2SO4 in concentrated sulfuric acid is 1:(1.0-1.1):(1.0-1.1):(1.1-1.2):(0.3-0.7).

7. The method for preparing the oxime ester photoinitiator OXE-02 according to claim 5, characterized in that: In step (2), the mixed solvent B is a mixed solvent of at least one of dichloroethane, chloroform and trichloroethane and water, wherein the volume fraction of water is 2-20%; And / or, the volume ratio of the compound of formula I-2 to the mixed solvent B is 1:(9-12).

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

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