阅读说明：本技术 一种（甲基）丙烯酸4-苯基苄基酯的制备方法 (Preparation method of 4-phenylbenzyl (meth) acrylate ) 是由 *** 张志鹏 苟金龙 周家栋 张芳芳 孙超 于 2019-04-23 设计创作，主要内容包括：本发明公开了一种(甲基)丙烯酸4-苯基苄基酯的制备方法,属于光固化树脂领域。该制备方法包括：在带水剂、酸类催化剂、抗氧剂以及第一阻聚剂存在的条件下,使4-联苯甲醇和(甲基)丙烯酸进行酯化反应,经后处理,得到所述(甲基)丙烯酸4-苯基苄基酯。通过使4-联苯甲醇和(甲基)丙烯酸进行直接酯化反应,反应原料低廉易得,反应工艺简单可控,可降低制备成本。同时,在酯化反应过程中,抗氧剂以及第一阻聚剂的加入,可有效遏制副反应的发生,利于获得高纯度高色度的(甲基)丙烯酸4-苯基苄基酯,同时简化后处理过程。酸类催化剂的加入,不仅利于提升反应速率,且利于提升(甲基)丙烯酸4-苯基苄基酯的纯度。(The invention discloses a preparation method of 4-phenylbenzyl (meth) acrylate, and belongs to the field of photocuring resin. The preparation method comprises the following steps: 4-biphenylmethanol and (methyl) acrylic acid are subjected to esterification reaction in the presence of a water-carrying agent, an acid catalyst, an antioxidant and a first polymerization inhibitor, and the (methyl) acrylic acid 4-phenylbenzyl ester is obtained after post-treatment. By directly esterifying 4-biphenylmethanol and (methyl) acrylic acid, the reaction raw materials are cheap and easy to obtain, the reaction process is simple and controllable, and the preparation cost can be reduced. Meanwhile, in the esterification reaction process, the addition of the antioxidant and the first polymerization inhibitor can effectively inhibit the occurrence of side reactions, is favorable for obtaining the high-purity and high-chroma 4-phenylbenzyl (meth) acrylate, and simplifies the post-treatment process. The addition of the acid catalyst is beneficial to improving the reaction rate and the purity of the 4-phenylbenzyl (meth) acrylate.)

1. A method for preparing 4-phenylbenzyl (meth) acrylate, comprising: 4-biphenylmethanol and (methyl) acrylic acid are subjected to esterification reaction in the presence of a water-carrying agent, an acid catalyst, an antioxidant and a first polymerization inhibitor, and the (methyl) acrylic acid 4-phenylbenzyl ester is obtained after post-treatment.

2. 4-phenylbenzyl (meth) acrylate production process according to claim 1, characterized in that the esterification reaction is carried out under negative pressure.

3. The method of producing 4-phenylbenzyl (meth) acrylate according to claim 1, wherein the water-carrying agent is toluene.

4. The process for producing 4-phenylbenzyl (meth) acrylate according to claim 1, wherein the first polymerization inhibitor is a mixture of a phenolic polymerization inhibitor and a copper salt polymerization inhibitor, and compressed air is introduced into the reaction system during the esterification reaction.

5. The method for producing 4-phenylbenzyl (meth) acrylate according to claim 1, wherein the acid catalyst is at least one selected from the group consisting of methanesulfonic acid, p-toluenesulfonic acid, and concentrated sulfuric acid.

6. The method of claim 1, wherein the antioxidant is at least one member selected from the group consisting of dibutylhydroxytoluene, pentaerythritol diphosphites, and hypophosphorous acid.

7. The process for the preparation of 4-phenylbenzyl (meth) acrylate according to claim 1, wherein the post-treatment comprises: sequentially carrying out primary water washing, alkaline washing, secondary water washing and reduced pressure distillation.

8. The process for producing 4-phenylbenzyl (meth) acrylate according to claim 7, wherein a second polymerization inhibitor is added to the reaction product during the distillation under reduced pressure.

9. The method for producing 4-phenylbenzyl (meth) acrylate according to claim 8, wherein the second polymerization inhibitor is a phenolic polymerization inhibitor.

10. The method for producing 4-phenylbenzyl (meth) acrylate according to any one of claims 1 to 9, wherein the end point of the esterification reaction is determined by measuring the acid value of the reaction system before the post-treatment.

Technical Field

The invention relates to the field of light-cured resin, in particular to a preparation method of 4-phenylbenzyl (meth) acrylate.

Background

For a backlight module of a Liquid crystal display device such as a Liquid Crystal Display (LCD) or a Thin Film Transistor (TFT), a brightness enhancement film is used to improve the light emitting efficiency of the entire backlight system. Currently, there is an increasing demand for brightness enhancement films with high refractive index, and phenylbenzyl (meth) acrylate, especially 4-phenylbenzyl (meth) acrylate, is a currently ideal resin monomer for producing brightness enhancement films with high refractive index due to its high refractive index and low viscosity.

Currently, phenylbenzyl (meth) acrylate can be prepared by the following method: first, benzyl phenyl (meth) acrylate can be obtained by reacting halogenated methylbiphenyl with a metal salt of (meth) acrylic acid such as potassium or sodium, but the raw material halogenated methylbiphenyl used in this method is expensive and the production cost is high. Secondly, benzyl alcohol and acryloyl chloride can be used as raw materials, triethylamine is used as an acid-binding agent, and benzyl (meth) acrylate is obtained through esterification, however, the method also has the problem that the cost of the raw material acryloyl chloride is high, in the reaction process, acryloyl chloride is easily coordinated with triethylamine to form a yellow brown salt, and the (meth) acrylate is obtained through post-treatment steps such as acid washing, alkali washing, water washing and the like. Thirdly, phenylbenzyl (meth) acrylate can be prepared by using phenylbenzyl alcohol and acryloyl chloride as raw materials and using an alkali solution as an acid-binding agent, but the method also has the problem of relatively high cost.

Therefore, it is important to solve the above problems by reducing the production cost of 4-phenylbenzyl (meth) acrylate and reducing the color of 4-phenylbenzyl (meth) acrylate.

Disclosure of Invention

In view of the above, the present invention provides a method for preparing 4-phenylbenzyl (meth) acrylate, which can solve the above technical problems. Specifically, the method comprises the following technical scheme:

a method of preparing 4-phenylbenzyl (meth) acrylate, the method comprising: 4-biphenylmethanol and (methyl) acrylic acid are subjected to esterification reaction in the presence of a water-carrying agent, an acid catalyst, an antioxidant and a first polymerization inhibitor, and the (methyl) acrylic acid 4-phenylbenzyl ester is obtained after post-treatment.

In one possible implementation, the esterification reaction is carried out under subatmospheric pressure.

In one possible implementation, the water-carrying agent is toluene.

In a possible implementation manner, the first polymerization inhibitor is a mixture of a phenolic polymerization inhibitor and a copper salt polymerization inhibitor, and compressed air is introduced into the reaction system during the esterification reaction.

In one possible implementation, the acid-based catalyst is selected from at least one of methanesulfonic acid, p-toluenesulfonic acid, and concentrated sulfuric acid.

In one possible implementation, the antioxidant is selected from at least one of dibutyl hydroxy toluene, pentaerythritol diphosphite, and hypophosphorous acid.

In one possible implementation, the post-processing includes: sequentially carrying out primary water washing, alkaline washing, secondary water washing and reduced pressure distillation.

In one possible implementation, a second polymerization inhibitor is added to the reaction product while the reduced pressure distillation is performed.

In one possible implementation, the second polymerization inhibitor is a phenolic polymerization inhibitor.

In one possible implementation manner, before the post-treatment, whether the esterification reaction reaches the end point is judged by measuring the acid value of the reaction system.

The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:

according to the preparation method of the 4-phenylbenzyl (meth) acrylate provided by the embodiment of the invention, the 4-biphenylmethanol and the (meth) acrylic acid are subjected to direct esterification reaction, so that the reaction raw materials are cheap and easy to obtain, the reaction process is simple and controllable, and the preparation cost can be reduced. Meanwhile, in the esterification reaction process, the addition of the antioxidant and the first polymerization inhibitor can effectively inhibit the occurrence of side reactions, is favorable for obtaining the high-purity and high-chroma 4-phenylbenzyl (meth) acrylate, and simplifies the post-treatment process. The addition of the acid catalyst is beneficial to improving the reaction rate and the purity of the 4-phenylbenzyl (meth) acrylate. Therefore, the preparation method of the 4-phenylbenzyl (meth) acrylate provided by the embodiment of the invention has the advantages of simple preparation process and low cost, and is beneficial to improving the chromaticity of the 4-phenylbenzyl (meth) acrylate.

Detailed Description

In order to make the technical solutions and advantages of the present invention more clear, embodiments of the present invention will be described in further detail below.

The embodiment of the invention provides a preparation method of 4-phenylbenzyl (meth) acrylate, which comprises the following steps: 4-biphenylmethanol and (methyl) acrylic acid are subjected to esterification reaction in the presence of a water-carrying agent, an acid catalyst, an antioxidant and a first polymerization inhibitor, and post-treatment is carried out to obtain the (methyl) acrylic acid 4-phenylbenzyl ester.

According to the preparation method of the 4-phenylbenzyl (meth) acrylate provided by the embodiment of the invention, the 4-biphenylmethanol and the (meth) acrylic acid are subjected to direct esterification reaction, so that the reaction raw materials are cheap and easy to obtain, the reaction process is simple and controllable, and the preparation cost can be reduced. Meanwhile, in the esterification reaction process, the addition of the antioxidant and the first polymerization inhibitor can effectively inhibit the occurrence of side reactions, is favorable for obtaining the high-purity and high-chroma 4-phenylbenzyl (meth) acrylate, and simplifies the post-treatment process. The addition of the acid catalyst is beneficial to improving the reaction rate and the purity of the 4-phenylbenzyl (meth) acrylate. Therefore, the preparation method of the 4-phenylbenzyl (meth) acrylate provided by the embodiment of the invention has the advantages of simple preparation process and low cost, and is beneficial to improving the chromaticity of the 4-phenylbenzyl (meth) acrylate.

In one possible example, 4-biphenylmethanol, (methyl) acrylic acid, an acid catalyst, an antioxidant and a first polymerization inhibitor are added into a reaction kettle, stirring is started, compressed air is introduced, the reaction temperature is kept at 80-95 ℃, and a certain negative pressure is maintained, so that direct esterification reaction is carried out.

4-biphenylmethanol and (meth) acrylic acid are esterified in a molar ratio of (meth) acrylic acid to 4-biphenylmethanol of 1 to 2:1, for example 1.1 to 1.2: 1.

Further, in order to maintain the reaction temperature at a low level and to avoid the occurrence of side reactions, the esterification reaction may be carried out under a negative pressure condition, wherein the required negative pressure may be 300Torr to 600Torr, for example, 400Torr to 500 Torr.

When the esterification reaction is carried out under the negative pressure condition, although the reaction temperature can be maintained at a lower level, the lower reaction temperature needs to satisfy the condition that the esterification reaction is carried out smoothly, which requires that the reaction temperature is not too low, at this time, toluene can be selected as the water carrying agent satisfying the above conditions, and the reaction temperature can be controlled to be 80-95 ℃.

The first polymerization inhibitor is used for preventing the reaction raw materials from generating polymerization reaction in the esterification reaction process, in order to improve the polymerization inhibition effect, the first polymerization inhibitor adopted in the embodiment of the invention is a mixture of a phenol polymerization inhibitor and a copper salt polymerization inhibitor, and compressed air is introduced into a reaction system during the esterification reaction. The phenol polymerization inhibitor and the copper salt polymerization inhibitor act synergistically to improve the polymerization inhibition effect, and meanwhile, when the phenol polymerization inhibitor is adopted, compressed air is introduced into the reaction system to provide the synergistic effect of oxygen and the phenol polymerization inhibitor, so that the polymerization inhibition effect is further improved, the occurrence of side reactions can be effectively inhibited, and the high-purity and high-chroma 4-phenylbenzyl (meth) acrylate is favorably obtained.

Wherein, the mass percent of the first polymerization inhibitor in the reaction system can be 0.06% -1.5%, wherein, the mass percent of the phenolic polymerization inhibitor in the reaction system can be 0.01% -0.5%, and the mass percent of the copper salt polymerization inhibitor in the reaction system can be 0.05% -1%.

For example, the phenolic polymerization inhibitor may be selected from p-hydroxyanisole, 2, 6-di-tert-butyl-p-cresol, etc., and the copper salt polymerization inhibitor may be selected from copper chloride, copper sulfate, etc.

The acid catalyst is selected from at least one of methanesulfonic acid, p-toluenesulfonic acid and concentrated sulfuric acid, wherein the mass fraction of the methanesulfonic acid and the p-toluenesulfonic acid can be 60-80%, for example 70%; the mass fraction of concentrated sulfuric acid may be 98%.

The mass percentage of the acid catalyst in the reaction system can be 1-1.5%, too much acid catalyst easily causes more side reactions, so that the treatment liquid is directly emulsified when the post-treatment alkali is neutralized, and a product cannot be obtained, and too little acid catalyst easily causes too low reaction catalysis efficiency, so that the raw material alcohol cannot react completely in the same reaction time, and the purity is reduced.

In the embodiment of the invention, the antioxidant is used for preventing the reaction product from being oxidized, preventing the color from darkening and ensuring high chroma of the reaction product, and the suitable antioxidant is selected from at least one of dibutyl hydroxy toluene (BHT), pentaerythritol diphosphite (antioxidant 636) and hypophosphorous acid.

Wherein, the mass percentage of the antioxidant in the reaction system can be 0.1-0.5%.

After the esterification reaction is finished, the reaction system needs to be post-treated to separate and obtain the 4-phenylbenzyl (meth) acrylate, and because a water-carrying agent, an acid catalyst, an antioxidant and a first polymerization inhibitor are involved in the reaction process, in order to completely remove the above substances, the post-treatment comprises the following steps: sequentially carrying out primary water washing, alkaline washing, secondary water washing and reduced pressure distillation.

For the first water washing, the reaction system solution containing the reaction product may be poured into a water washing kettle, the solvent and deionized water are added into the water washing kettle, and after stirring for a period of time (8-15min, e.g., 10min), the mixture is allowed to stand (e.g., for 1h), and the lower layer wastewater is discharged. By the first water washing, excess acid (e.g., (meth) acrylic acid, acid-based catalyst, antioxidant) and copper salt-based polymerization inhibitor can be removed.

In order to sufficiently remove acid in the reaction system, alkali washing can be performed after the first water washing, wherein the alkali washing process can be performed by adding a theoretically calculated amount of alkali solution (the mass concentration of the alkali solution can be 10%) into the water washing kettle, stirring for a period of time (8-15min, for example, 10min), standing (for example, standing for 1h), and discharging the lower layer wastewater. Wherein, the alkali solution can be neutralized with acid to form salt, which is convenient for subsequent and thorough removal.

The alkali solution may be any one of a sodium hydroxide solution, a potassium hydroxide solution, and a sodium carbonate solution having a mass concentration of 10%, and the amount of the alkali solution may be 10% to 100%, for example, 20% to 50% more than the theoretical amount.

After the alkaline washing, a second water washing is performed to remove salts generated after the alkaline washing and residual alkaline solution, deionized water may be added into the water washing kettle, stirred for a period of time (8-15min, for example, 10min), and then left to stand (for example, 1h), and the lower layer wastewater is discharged. Further, the water washing may be repeated once in order to improve the purification effect.

Wherein, in the first water washing and the second water washing, the adding mass of the deionized water can be 10-30% of the total mass of the reaction system solution.

And finally, carrying out reduced pressure distillation to remove the water-carrying agent. The method comprises the steps of transferring a reaction product solution washed in a washing kettle into a reaction kettle, adding a second polymerization inhibitor, controlling the temperature to be 60-80 ℃, removing a water-carrying agent under reduced pressure until the content of the water-carrying agent is less than 500ppm, and filtering to obtain light yellow transparent 4-phenylbenzyl (meth) acrylate.

The second polymerization inhibitor can effectively prevent the self-polymerization reaction of the 4-phenylbenzyl (meth) acrylate. Among them, in order to ensure high chroma of 4-phenylbenzyl (meth) acrylate, the second polymerization inhibitor may be a phenolic polymerization inhibitor such as p-hydroxyanisole or 2, 6-di-t-butyl-p-cresol. The second polymerization inhibitor may be, for example, 0.05% to 0.1%, for example, 0.05% to 0.08%, by mass, based on the mass of 4-phenylbenzyl (meth) acrylate.

In the preparation method provided by the embodiment of the invention, in order to accurately judge the end point of the esterification reaction, whether the esterification reaction reaches the end point is judged by measuring the acid value of the reaction system before the post-treatment. Wherein, after the esterification reaction is carried out for a certain time, for example, 5-6h, the acid value measurement is started, the acid value is measured every 30min-1h, and the reaction is stopped when the acid value reaches the theoretical acid value.

In summary, the preparation method provided by the embodiment of the invention for preparing 4-phenylbenzyl (meth) acrylate has at least the following advantages:

firstly, because the (methyl) acryloyl chloride is not used as the raw material of the esterification reaction, organic alkali such as triethylamine is not used, a large amount of triethylamine hydrochloride is not generated in the reaction process, the preparation method is clean and environment-friendly, the post-treatment is simple, the pollution to the environment is small only by simple water washing and alkali neutralization, and the (methyl) acrylic acid 4-phenylbenzyl ester with lighter color can be obtained without column purification.

Secondly, the preparation method of the 4-phenylbenzyl (meth) acrylate by the direct esterification method is simple in process, low in cost and suitable for industrial production, and the 4-phenylbenzyl (meth) acrylate with high purity and yield can be obtained by the preparation method provided by the embodiment of the invention, and the purity and yield are both over 90%.

Thirdly, the preparation method provided by the embodiment of the invention can react at relatively low temperature by reacting under negative pressure, thereby reducing the generation of by-products and simplifying the post-treatment.

Fourthly, a large number of experiments prove that the acid catalyst with proper concentration can be added to effectively catalyze the reaction, so that the purity of the direct reaction product is improved, and the reaction rate can be effectively improved.

Fifthly, in the post-treatment process, the embodiment of the invention uses the alkali solution with proper concentration, which is not only beneficial to removing the acid in the alkali solution, but also effectively prevents the emulsification phenomenon of the reaction product in the post-treatment process and improves the synthesis yield.

The final reaction product prepared by the embodiment of the invention is subjected to infrared spectrum test and nuclear magnetic resonance hydrogen spectrum test, and the test results show that the preparation method provided by the invention can be used for preparing the (methyl) acrylic acid 4-phenylbenzyl ester.

The appearance of the 4-phenylbenzyl (meth) acrylate prepared by the method provided in the present invention was observed, and the obtained product was light yellow and transparent, and had low color. The refractive index was measured by Abbe refractometer, and as a result, the refractive index of the prepared 4-phenylbenzyl (meth) acrylate was 1.592(25 ℃ C.). The viscosity was measured using a BrookF IELD DV-II + Pro laminar viscometer, and the prepared 4-phenylbenzyl (meth) acrylate had a viscosity of 20-30cps (25 ℃ C.). The purity of the prepared 4-phenylbenzyl (meth) acrylate was measured by Agilent1260 High Performance Liquid Chromatography (HPLC), and the test result showed that the purity of the prepared 4-phenylbenzyl (meth) acrylate was 90% to 93%. The yield of the 4-phenylbenzyl (meth) acrylate prepared by the method provided by the invention is calculated according to the ratio of the actual yield to the theoretical yield, and the calculated result is that the yield of the 4-phenylbenzyl (meth) acrylate prepared by the method provided by the embodiment of the invention is 90-95%.

The invention will be further described by the following specific examples: