A method for preparing a methacrylate photoresist resin monomer

Abstract

This invention belongs to the field of chemical synthesis and photoresist technology, specifically relating to a method for preparing methacrylate-based photoresist resin monomers. The method includes the following steps: S1, under inert gas conditions, 2,6-dihydroxybenzoic acid is used as a raw material and reacted with acetone in a molecular sieve catalysis to undergo a condensation esterification reaction, yielding intermediate 1; S2, intermediate 1 from step S1 is salted with an inorganic base and dissolved in a solvent, then esterified with an acylating agent under the action of a catalyst to obtain the methacrylate-based photoresist resin monomer. This preparation method uses molecular sieve catalysis, which avoids chlorination and decarboxylation impurities, resulting in high yield, high purity, and no toxic gas generation, making the production process environmentally friendly. Water is used as a solvent in the esterification stage, facilitating post-processing of the product. The use of methacrylic anhydride as the acylating agent reduces cost and enables large-scale production.

Description

Technical Field

[0001] This invention specifically relates to a method for preparing methacrylate-based photoresist resin monomers, belonging to the fields of chemical synthesis and photoresist technology. Background Technology

[0002] Chemically enhanced photoresists are commonly used for high-resolution processing. These photoresists typically employ polymers with acid-indestabilizing groups, photoacid generators, and acid-quenching materials. Despite some technological advancements in this field, there remains a persistent need for photoresist compositions that can be used to increase pattern density, including those that can achieve lower photosensitivity and lower LWR for line or spatial patterns.

[0003] Existing polymer resins containing methacrylate-based photoresist monomers exhibit better etching resistance and can improve the resolution of photoresist patterns. However, the synthesis process of methacrylate-based photoresist monomers often generates toxic gases such as sulfur dioxide and hydrogen chloride, causing environmental harm. Patent application CN118027269A discloses a polymer, a photoresist composition containing the same, and a patterning method. This patent application discloses a method for synthesizing monomers containing methacrylate units, a resin containing this structural unit, a photoacid-generating agent composition containing the same, and a patterning method. The synthetic route for monomers containing methacrylate units is shown below:

[0004] This patent describes a process using 2,6-dihydroxybenzoic acid as a raw material, which undergoes a condensation reaction with acetone under the catalysis of thionyl chloride to obtain an intermediate. This synthetic step has a yield of only 39%, produces a significant amount of chlorinated and decarboxylated impurities, and is difficult to purify. Furthermore, it generates toxic gases such as sulfur dioxide and hydrogen chloride, causing environmental harm. The subsequent esterification reaction with methacryloyl chloride yields the final product. Methacryl chloride is expensive, has an irritating odor, and is inconvenient to transport, hindering industrial production.

[0005] In summary, the existing technology has obvious shortcomings. It is of great significance to develop a method for preparing methacrylate photoresist monomers that has high yield, high purity, low cost, environmental friendliness, and can be mass-produced. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a method for preparing acrylate-based photoresist resin monomers. This method uses molecular sieve catalysis, which avoids chlorination and decarboxylation impurities, resulting in high yield, high purity, and no toxic gas generation, making the production process environmentally friendly. Water is used as a solvent in the esterification stage, facilitating post-reaction processing. Methacrylic anhydride is used as the acylation reagent, resulting in lower cost and enabling large-scale production.

[0007] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing methacrylate photoresist resin monomers, comprising the following steps:

[0008] S1. Under inert gas conditions, 2,6-dihydroxybenzoic acid was reacted with acetone in a condensation ester cyclization reaction catalyzed by molecular sieve to obtain intermediate 1.

[0009] S2. The intermediate 1 from step S1 is dissolved in a solvent after forming a salt with an inorganic base. Under the action of a catalyst, it undergoes an esterification reaction with an acylating agent to obtain a methacrylate photoresist resin monomer.

[0010] Furthermore, in step S1, the molar ratio of 2,6-dihydroxybenzoic acid to acetone is 1:(1~5).

[0011] In step S1, the mass ratio of 2,6-dihydroxybenzoic acid to the molecular sieve is 1:(0.1~0.5).

[0012] Furthermore, in step S2, the molar ratio between the intermediate 1, the inorganic base, the catalyst, and the acylating agent is 1:(1~2):(0.05~0.2):(0.8~2), wherein the molar ratio of the intermediate 1 to the catalyst is preferably 1:0.1.

[0013] Furthermore, in step S1, the reaction temperature for the condensation ester cyclization is 50~140℃, preferably 50~70℃.

[0014] Furthermore, in step S2, the temperature of the esterification reaction is 0~30℃, preferably 0~10℃.

[0015] Furthermore, in step S1, the condensation ester cyclization reaction takes 5 to 20 hours, preferably 8 to 15 hours.

[0016] Furthermore, in step S2, the esterification reaction takes 0.5 to 5 hours, preferably 1 to 2 hours.

[0017] Furthermore, in step S1, the solvent is at least one of toluene, xylene, and n-heptane, preferably toluene.

[0018] Furthermore, in step S2, the solvent is at least one of dichloromethane, ethyl acetate, tetrahydrofuran, and water, preferably water.

[0019] Furthermore, in step S2, the acylating agent is methacrylic anhydride.

[0020] Furthermore, in step S2, the inorganic base is at least one selected from sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, preferably sodium hydroxide.

[0021] Furthermore, in step S1, the molecular sieve is at least one of hydrogen-type zeolite molecular sieves.

[0022] Furthermore, the hydrogen-type zeolite molecular sieve is at least one of the following: H-β molecular sieve, HZSM-5, USY, mordenite, and TS-1, with HZSM-5 being more preferred.

[0023] Further, in step S2, the catalyst is at least one of 4-dimethylaminopyridine (DMAP), 4-pyrrolidinylpyridine (4-PPY), 1-hydroxybenzotriazole (HOBt), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), and N,N-diisopropylethylamine (DIPEA), preferably DMAP.

[0024] The beneficial effects of this invention are:

[0025] (1) The method provided by this invention uses 2,6-dihydroxybenzoic acid as the starting material. In step S1, molecular sieves are selected as catalysts for the condensation ester cyclization reaction, which reduces the generation of by-products, avoids chlorination and decarboxylation impurities, and achieves high yield and product purity while being environmentally friendly. This lays a high-quality raw material foundation for subsequent steps and is more suitable for industrial-scale production.

[0026] (2) In step S2 of the method provided by the present invention, intermediate 1 is first salted with an inorganic base. This operation converts the phenolic hydroxyl group into a more nucleophilic phenol oxide anion, which greatly improves its activity and rate in the esterification reaction with the acylating agent. At the same time, the salting step helps to purify the intermediate by recrystallization and other methods, effectively removing impurities and ensuring the high purity of the final monomer product, which is crucial for the performance of the photoresist resin.

[0027] (3) The raw materials used in the preparation method provided by the present invention are readily available, the catalyst is low in cost and recyclable, the simplification of the reaction steps reduces energy consumption and waste emissions, and the overall process route conforms to the principles of green chemistry, with significant economic benefits and environmental advantages. Attached Figure Description

[0028] Figure 1 The GC-MS spectrum of the product in Example 1;

[0029] Figure 2 The 1H NMR spectrum of the product in Example 1;

[0030] Figure 3 The image shows the carbon NMR spectrum of the product in Example 1. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below. The present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used is for describing particular embodiments only and is not intended to limit the invention.

[0033] All materials and reagents used in the embodiments of this invention are commercially purchased, and any special circumstances will be explained.

[0034] The present invention provides a method for preparing a methacrylate-based photoresist resin monomer, comprising the following steps:

[0035] S1. Under inert gas conditions, 2,6-dihydroxybenzoic acid was reacted with acetone in a condensation ester cyclization reaction catalyzed by molecular sieve to obtain intermediate 1.

[0036] S2. The intermediate 1 from step S1 is dissolved in a solvent after forming a salt with an inorganic base. Under the action of a catalyst, it undergoes an esterification reaction with an acylating agent to obtain a methacrylate photoresist resin monomer.

[0037] The synthesis process route for methacrylate photoresist resin monomers is as follows:

[0038] .

[0039] In this embodiment of the invention, the inert gas condition is provided by nitrogen, but this is not a limitation of the invention. As long as the reaction system can be guaranteed to be an inert environment, other gases, such as argon, can be selected as needed to ensure the inert environment.

[0040] Specifically, in step S1, the molar ratio of 2,6-dihydroxybenzoic acid to acetone is 1:(1~5).

[0041] Specifically, in step S1, the mass ratio of 2,6-dihydroxybenzoic acid to the molecular sieve is 1:(0.1~0.5).

[0042] Specifically, in step S2, the molar ratio between the intermediate 1, the inorganic base, the catalyst, and the acylating agent is 1:(1~2):(0.05~0.2):(0.8~2), wherein the molar ratio of the intermediate 1 to the catalyst is preferably 1:0.1.

[0043] Specifically, in step S1, the reaction temperature for the condensation ester cyclization is 50~140℃, preferably 50~70℃.

[0044] Specifically, in step S2, the temperature of the esterification reaction is 0~30℃, preferably 0~10℃.

[0045] Specifically, in step S1, the condensation ester cyclization reaction takes 5 to 20 hours, preferably 8 to 15 hours.

[0046] Specifically, in step S2, the esterification reaction takes 0.5 to 5 hours, preferably 1 to 2 hours.

[0047] Specifically, in step S1, the solvent is at least one of toluene, xylene, and n-heptane, preferably toluene.

[0048] Specifically, in step S2, the solvent is at least one of dichloromethane, ethyl acetate, tetrahydrofuran, and water, preferably water.

[0049] Specifically, in step S2, the acylating agent is methacrylic anhydride.

[0050] Specifically, in step S2, the inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, preferably sodium hydroxide.

[0051] Specifically, in step S1, the molecular sieve is at least one of hydrogen-type zeolite molecular sieves.

[0052] More specifically, the hydrogen-type zeolite molecular sieve is at least one of the following: H-β molecular sieve, HZSM-5, USY, mordenite, and TS-1, with HZSM-5 being more preferred.

[0053] Specifically, in step S2, the catalyst is at least one of 4-dimethylaminopyridine (DMAP), 4-pyrrolidinylpyridine (4-PPY), 1-hydroxybenzotriazole (HOBt), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI), and N,N-diisopropylethylamine (DIPEA), preferably DMAP.

[0054] More specifically, the preparation method of a methacrylate photoresist resin monomer involved in the embodiments of the present invention specifically includes the following steps:

[0055] S1. Under nitrogen atmosphere, add 2,6-dihydroxybenzoic acid, molecular sieve, solvent and acetone to a three-necked flask; heat to the reaction temperature, reflux to remove water and carry out condensation ester cyclization reaction.

[0056] After the reaction is completed, post-processing operations are performed, including: cooling the reaction system to room temperature, washing the reaction solution with water, and collecting the organic phase; concentrating the organic phase to obtain the crude product, purifying the crude product by silica gel column chromatography, using a mixed solvent of ethyl acetate and toluene as the mobile phase, with a mass ratio of ethyl acetate to toluene of 1:(3~6); recrystallizing the product purified by silica gel column chromatography by n-heptane, and drying to obtain the white solid as intermediate 1.

[0057] S2. Weigh intermediate 1 from step S1 into a three-necked flask, add solvent and inorganic base, stir until the system is completely dissolved, and then add catalyst. Weigh acylating agent methacrylic anhydride and slowly add it to the reaction system to carry out esterification reaction.

[0058] After the reaction, post-processing operations were performed, specifically including: weighing 10% K2CO3 aqueous solution and adding it to the reaction solution for washing with water for 30 min to separate the organic phase. The organic phase was washed successively with 5% HCl aqueous solution and deionized water, and finally dried with anhydrous sodium sulfate, filtered, and collected. The organic phase was dried to obtain the crude product; the crude product was purified by silica gel column chromatography using a mixed solvent of toluene and n-heptane as the mobile phase, with a mass ratio of toluene to n-heptane of 1:(3~6); the product purified by silica gel column chromatography was purified by recrystallization using a mixed solvent of toluene and n-heptane, and the white solid obtained after drying was the target product, methacrylate photoresist resin monomer.

[0059] Example 1

[0060] The preparation of a methacrylate-based photoresist resin monomer specifically includes the following steps:

[0061] S1. Under nitrogen atmosphere, add 15.4g (0.100mol) 2,6-dihydroxybenzoic acid, 3.1g HZSM-5 molecular sieve, 120g toluene and 11.6g (0.200mol) acetone to a three-necked flask; heat to 110~120℃ for reaction, reflux for water removal for 10h to carry out condensation ester cyclization reaction.

[0062] After the reaction was completed, post-processing operations were performed, including: cooling the reaction system to room temperature, washing the reaction solution with water, and collecting the organic phase; concentrating the organic phase to obtain the crude product, which was then purified by silica gel column chromatography using a mixture of ethyl acetate and toluene as the mobile phase, with a mass ratio of ethyl acetate to toluene of 1:(3~6); recrystallizing the purified product from silica gel column chromatography into n-heptane, and drying it to obtain 18.4 g of white solid, designated as intermediate 1, with a yield of 95.0% (based on 2,6-dihydroxybenzoic acid).

[0063] S2. Weigh 18.4g (0.095mol) of intermediate 1 from step S1 into a three-necked flask, add 200g of water and 5.7g (0.143mol) of sodium hydroxide, stir until the system is completely dissolved, add 1.16g of catalyst DMAP, weigh 17.6g (0.114mol) of acylating agent methacrylic anhydride and slowly add it to the reaction system, and keep the reaction at 10~20℃ for 1h.

[0064] After the reaction, post-processing was performed, including: weighing 100g of 10% K₂CO₃ aqueous solution and adding it to the reaction solution for washing with water for 30 min to separate the organic phase. The organic phase was then washed successively with 50g of 5% HCl aqueous solution and 100g of deionized water, and finally dried with anhydrous sodium sulfate, filtered, and the organic phase was collected. After drying the organic phase, the crude product was obtained. The crude product was purified by silica gel column chromatography using a mixed solvent of toluene and n-heptane as the mobile phase, with a mass ratio of toluene to n-heptane of 1:(3~6). The product purified by silica gel column chromatography was then purified by recrystallization using a mixed solvent of toluene and n-heptane, and after drying, 21.1g of the target product, methacrylate photoresist resin monomer, was obtained, with a yield of 80.7% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 99.5%. The GC-MS spectrum is shown below. Figure 1 As shown; the 1H NMR spectrum of the product is shown below. Figure 2 As shown, hydrogen spectrum analysis: 1 ¹H NMR (500 MHz, DMSO): δ = 1.637–1.651 (s, 6H), δ = 1.967 (s, 3H), δ = 5.858–5.865 (t, 1H), δ = 6.233 (t, 1H), δ = 6.960–7.022 (dd, 2H), δ = 7.040–7.686 (t, 1H) ppm. The carbon NMR spectrum of the product is shown below. Figure 3 As shown, carbon spectrum analysis: 13 C (101 MHz, DMSO): δ=165.508, 157.774, 156.941,151.459, 137.651, 135.542, 128.595, 118.178, 115.764, 107.618, 106.765,25.513, 18.499ppm.

[0065] Example 2

[0066] The preparation of a methacrylate-based photoresist resin monomer specifically includes the following steps:

[0067] S1. Under nitrogen conditions, add 15.4g (0.100mol) 2,6-dihydroxybenzoic acid, 1.6g HZSM-5 molecular sieve, 120g toluene and 5.8g (0.100mol) acetone to a three-necked flask; heat to 110~120℃ for reaction, and reflux for 10h to remove water for condensation ester cyclization reaction.

[0068] After the reaction was completed, post-processing operations were performed, including: cooling the reaction system to room temperature, washing the reaction solution with water, and collecting the organic phase; concentrating the organic phase to obtain the crude product, which was purified by silica gel column chromatography using a mixture of ethyl acetate and toluene as the mobile phase, with a mass ratio of ethyl acetate to toluene of 1:(3~6); recrystallizing the purified product from silica gel column chromatography into n-heptane, and drying it to obtain 16.5 g of white solid, designated as intermediate 1, with a yield of 85.0% (based on 2,6-dihydroxybenzoic acid).

[0069] S2. Weigh 16.5g (0.085mol) of intermediate 1 from step S1 into a three-necked flask, add 200g of water and 4.8g (0.12mol) of sodium hydroxide, stir until the system is completely dissolved, add 2.08g of catalyst DMAP, weigh 15.7g (0.102mol) of acylating agent methacrylic anhydride and slowly add it to the reaction system, and keep the reaction at 10~20℃ for 1h.

[0070] After the reaction, post-processing was performed, including: weighing 100g of 10% K2CO3 aqueous solution and adding it to the reaction solution for washing with water for 30 min to separate the organic phase. The organic phase was then washed successively with 50g of 5% HCl aqueous solution and 100g of deionized water, and finally dried with anhydrous sodium sulfate, filtered, and the organic phase was collected. The organic phase was dried to obtain the crude product. The crude product was purified by silica gel column chromatography using a mixed solvent of toluene and n-heptane as the mobile phase, with a mass ratio of toluene to n-heptane of 1:(3~6). The product purified by silica gel column chromatography was then purified by recrystallization using a mixed solvent of toluene and n-heptane, and dried to obtain 18.9g of the target product, methacrylate photoresist resin monomer, with a yield of 72.2% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 99.1%.

[0071] Example 3

[0072] The preparation of a methacrylate-based photoresist resin monomer specifically includes the following steps:

[0073] S1. Under nitrogen atmosphere, add 15.4g (0.100mol) 2,6-dihydroxybenzoic acid, 3.1g HZSM-5 molecular sieve, 120g toluene and 11.6g (0.200mol) acetone to a three-necked flask; heat to 110~120℃ for reaction, reflux for water removal for 10h to carry out condensation ester cyclization reaction.

[0074] After the reaction was completed, post-processing operations were performed, including: cooling the reaction system to room temperature, washing the reaction solution with water, and collecting the organic phase; concentrating the organic phase to obtain the crude product, which was then purified by silica gel column chromatography using a mixture of ethyl acetate and toluene as the mobile phase, with a mass ratio of ethyl acetate to toluene of 1:(3~6); recrystallizing the purified product from silica gel column chromatography into n-heptane, and drying it to obtain 18.4 g of white solid, designated as intermediate 1, with a yield of 95.0% (based on 2,6-dihydroxybenzoic acid).

[0075] S2. Weigh 18.4g (0.095mol) of intermediate 1 from step S1 into a three-necked flask, add 200g of water and 5.7g (0.143mol) of sodium hydroxide, stir until the system is completely dissolved, add 0.58g of catalyst DMAP, weigh 14.6g (0.095mol) of acylating agent methacrylic anhydride and slowly add it to the reaction system, and keep the reaction at 10~20℃ for 1h.

[0076] After the reaction, post-processing was performed, specifically including: weighing 100g of 10% K2CO3 aqueous solution and adding it to the reaction solution for washing with water for 30 min to separate the organic phase. The organic phase was washed successively with 50g of 5% HCl aqueous solution and 100g of deionized water, and finally dried with anhydrous sodium sulfate, filtered, and the organic phase was collected. The organic phase was dried to obtain the crude product. The crude product was purified by silica gel column chromatography using a mixed solvent of toluene and n-heptane as the mobile phase, with a mass ratio of toluene to n-heptane of 1:(3~6). The product purified by silica gel column chromatography was purified by recrystallization with a mixed solvent of toluene and n-heptane, and dried to obtain 19.9g of the target product, methacrylate photoresist resin monomer, with a yield of 76.1% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 99.0%.

[0077] Example 4

[0078] The preparation of a methacrylate-based photoresist resin monomer specifically includes the following steps:

[0079] S1. Under nitrogen atmosphere, add 15.4g (0.100mol) 2,6-dihydroxybenzoic acid, 3.1g HZSM-5 molecular sieve, 120g xylene and 11.6g (0.200mol) acetone to a three-necked flask; heat to 130~140℃ and reflux for 10h to carry out condensation ester cyclization reaction.

[0080] After the reaction was completed, post-processing operations were performed, including: cooling the reaction system to room temperature, washing the reaction solution with water, and collecting the organic phase; concentrating the organic phase to obtain the crude product, which was then purified by silica gel column chromatography using a mixture of ethyl acetate and toluene as the mobile phase, with a mass ratio of ethyl acetate to toluene of 1:(3~6); recrystallizing the purified product from silica gel column chromatography into n-heptane, and drying it to obtain 17.5 g of white solid, designated as intermediate 1, with a yield of 90.2% (based on 2,6-dihydroxybenzoic acid).

[0081] S2. Weigh 17.5g (0.090mol) of intermediate 1 from step S1 into a three-necked flask, add 200g of water and 5.7g (0.143mol) of sodium hydroxide, stir until the system is completely dissolved, add 1.11g of catalyst DMAP, weigh 27.6g (0.180mol) of acylating agent methacrylic anhydride and slowly add it to the reaction system, and keep the reaction at 10~20℃ for 1h.

[0082] After the reaction, post-processing was performed, including: weighing 100g of 10% K2CO3 aqueous solution and adding it to the reaction solution for washing with water for 30 min to separate the organic phase. The organic phase was then washed successively with 50g of 5% HCl aqueous solution and 100g of deionized water, and finally dried with anhydrous sodium sulfate, filtered, and the organic phase was collected. The organic phase was dried to obtain the crude product. The crude product was purified by silica gel column chromatography using a mixed solvent of toluene and n-heptane as the mobile phase, with a mass ratio of toluene to n-heptane of 1:(3~6). The product purified by silica gel column chromatography was then purified by recrystallization using a mixed solvent of toluene and n-heptane, and dried to obtain 19.6g of the target product, methacrylate photoresist resin monomer, with a yield of 74.9% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 99.3%.

[0083] Example 5

[0084] The preparation of a methacrylate-based photoresist resin monomer specifically includes the following steps:

[0085] S1. Under nitrogen atmosphere, add 15.4g (0.100mol) 2,6-dihydroxybenzoic acid, 3.1g HZSM-5 molecular sieve, 120g toluene and 11.6g (0.200mol) acetone to a three-necked flask; heat to 110~120℃ for reaction, reflux for water removal for 10h to carry out condensation ester cyclization reaction.

[0086] After the reaction was completed, post-processing operations were performed, including: cooling the reaction system to room temperature, washing the reaction solution with water, and collecting the organic phase; concentrating the organic phase to obtain the crude product, which was purified by silica gel column chromatography using a mixture of ethyl acetate and toluene as the mobile phase, with a mass ratio of ethyl acetate to toluene of 1:(3~6); recrystallizing the purified product from silica gel column chromatography into n-heptane, and drying it to obtain 17.6 g of white solid, designated as intermediate 1, with a yield of 90.4% (based on 2,6-dihydroxybenzoic acid).

[0087] S2. Weigh 17.6g (0.091mol) of intermediate 1 from step S1 into a three-necked flask, add 200g of dichloromethane and 5.7g (0.143mol) of sodium hydroxide, stir until the system is completely dissolved, add 1.11g of catalyst DMAP, weigh 21.0g (0.136mol) of acylating agent methacrylic anhydride and slowly add it to the reaction system, and keep the reaction at 10~20℃ for 1h.

[0088] After the reaction, post-processing was performed, specifically including: weighing 100g of 10% K2CO3 aqueous solution and adding it to the reaction solution for washing with water for 30 min to separate the organic phase. The organic phase was washed successively with 50g of 5% HCl aqueous solution and 100g of deionized water, and finally dried with anhydrous sodium sulfate, filtered, and the organic phase was collected. The organic phase was dried to obtain the crude product. The crude product was purified by silica gel column chromatography using a mixed solvent of toluene and n-heptane as the mobile phase, with a mass ratio of toluene to n-heptane of 1:(3~6). The product purified by silica gel column chromatography was purified by recrystallization from the mixed solvent of toluene and n-heptane, and dried to obtain 18.2g of the target product, methacrylate photoresist resin monomer, with a yield of 69.6% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 98.9%.

[0089] Comparative Example 1

[0090] The preparation of a methacrylate photoresist resin monomer: Comparative Example 1 uses the same method as Example 1, except that in step S1, 7g of HZSM-5 molecular sieve was added. After post-treatment, 17.1g of intermediate 1 was obtained, with a yield of 88.4% (based on 2,6-dihydroxybenzoic acid). The reaction in step S2 was not performed.

[0091] The experimental results from Comparative Example 1 and Example 1 show that in step S1, when the amount of molecular sieve is small, the yield of intermediate 1 will decrease significantly. This is because when the amount of molecular sieve is low, the reaction in step S1 is incomplete, which affects the yield of intermediate 1.

[0092] Comparative Example 2

[0093] The preparation of a methacrylate-based photoresist resin monomer was carried out in Comparative Example 2 using the same method as in Example 1, except that the reaction temperature in step S2 was 50°C. After the reaction, post-treatment purification was performed to obtain 17.9 g of the target product, the methacrylate-based photoresist resin monomer, with a yield of 68.4% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 97.4%.

[0094] The experimental results from Comparative Example 2 and Example 1 show that in step S2, when the reaction temperature is too high, the yield and purity of the target product will decrease. This is because when the reaction temperature in step S2 is too high, impurities will be generated, and the ester bond of the intermediate salt formed by intermediate 1 will be broken, and intermediate 1 will be regenerated, affecting the activity of the esterification reaction in step S2, and thus affecting the yield and purity of the product.

[0095] Comparative Example 3

[0096] The preparation of a methacrylate photoresist resin monomer was carried out in Comparative Example 3 using the same method as in Example 1, except that in step S2, 11.4 g of sodium hydroxide was added, at which point the molar ratio of intermediate 1 to inorganic base was 1:3. After the reaction was completed, post-treatment purification was performed to obtain 19.4 g of the target product, the methacrylate photoresist resin monomer, with a yield of 74.1% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 96.8%.

[0097] The experimental results from Comparative Example 3 and Example 1 show that in step S2, when 11.4g of sodium hydroxide is added, the yield and purity of the target product decrease. This is because when 11.4g of sodium hydroxide is added, the inorganic base is in excess, and the reaction system is too alkaline, which will cause the ester bond of the intermediate salt formed by intermediate 1 to break, and intermediate 1 will be regenerated, affecting the activity of the esterification reaction in step S2, and ultimately affecting the yield and purity of the product.

[0098] Comparative Example 4

[0099] The preparation of a methacrylate-based photoresist resin monomer was carried out in Comparative Example 4 using the same method as in Example 1, except that in step S2, 5.8 g of the catalyst DMAP was added, at which point the molar ratio of intermediate 1 to the catalyst was 1:0.5. After the reaction was completed, post-treatment purification was performed to obtain 18.9 g of the target product, the methacrylate-based photoresist resin monomer, with a yield of 72.3% (based on 2,6-dihydroxybenzoic acid) and a gas chromatographic purity of 95.7%.

[0100] The experimental results from Comparative Example 4 and Example 1 show that when the amount of catalyst used in step S2 is too high, the yield and purity of the target product will decrease. This is because when the amount of catalyst used in step S2 is too high, it is difficult to remove impurities during the post-processing purification process in step S2, resulting in excessive product loss during the purification process, which leads to a decrease in the yield and purity of the product.

[0101] In summary, the yield and purity data of the intermediates and target products in the examples and comparative examples are shown in Table 1.

[0102] Table 1. Yield and purity data from the examples and comparative examples.

[0103]

[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A method for preparing a methacrylate-based photoresist resin monomer, characterized in that, The preparation method includes the following steps: S1. Under inert gas conditions, 2,6-dihydroxybenzoic acid was reacted with acetone in a condensation ester cyclization reaction catalyzed by molecular sieve to obtain intermediate 1. S2. After intermediate 1 from step S1 forms a salt with an inorganic base, it is dissolved in a solvent and then undergoes an esterification reaction with an acylating agent under the action of a catalyst to obtain a methacrylate photoresist resin monomer. In step S2, the acylating agent is methacrylic anhydride; In step S2, the inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; In step S1, the molecular sieve is a hydrogen-type zeolite molecular sieve; In step S2, the catalyst is 4-dimethylaminopyridine; In step S1, the mass ratio of 2,6-dihydroxybenzoic acid to the molecular sieve is 1:(0.1~0.5). In step S2, the molar ratio of the intermediate 1, the inorganic base, the catalyst, and the acylating agent is 1:(1~2):(0.05~0.2):(0.8~2). In step S1, the reaction temperature for the condensation ester cyclization is 50~140℃; In step S2, the temperature of the esterification reaction is 0~30℃.

2. The method for preparing a methacrylate photoresist resin monomer according to claim 1, characterized in that, In step S1, the molar ratio of 2,6-dihydroxybenzoic acid to acetone is 1:(1~5).

3. The method for preparing a methacrylate photoresist resin monomer according to claim 1, characterized in that, In step S1, the condensation ester cyclization reaction takes 5 to 20 hours; In step S2, the esterification reaction takes 0.5 to 5 hours.

4. The method for preparing a methacrylate photoresist resin monomer according to claim 1, characterized in that, In step S1, the solvent is at least one of toluene, xylene, and n-heptane; In step S2, the solvent is at least one of dichloromethane, ethyl acetate, tetrahydrofuran, and water.

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