Trifluoroethyl methacrylate and its synthesis method

Abstract

The present invention belongs to the technical field of fluorine chemical industry, and in particular to trifluoroethyl methacrylate and a synthesis method thereof. The synthesis method of trifluoroethyl methacrylate of the present invention comprises the following steps: firstly, a solvent, methyl methacrylate, a catalyst, and a polymerization inhibitor are mixed, the temperature is raised to 25-70°C, and then a by-product chlorotrifluoroethane is introduced, and the reaction is carried out for 4-6 hours after the addition is completed, and finally the reaction solution is post-processed to obtain trifluoroethyl methacrylate. The optimal reaction temperature is within the range of 25-50°C. The synthesis method of trifluoroethyl methacrylate provided by the present invention utilizes waste gas chlorotrifluoroethane, has a high conversion rate, is environmentally friendly, and can realize industrial synthesis. The yield of trifluoroethyl methacrylate synthesized by the present invention is high and the content is high.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorine chemical industry, and particularly relates to trifluoroethyl methacrylate and a synthesis method thereof. Background Art

[0002] Trifluoroethyl methacrylate is an important organic synthesis intermediate, which is widely used in fluorine-containing coatings, optical fibers, contact lenses, etc. At present, the preparation method of trifluoroethyl methacrylate still has some shortcomings, such as harsh reaction conditions, high cost, low yield, etc.

[0003] 2-Chloro-1,1,1-trifluoroethane, also known as chlorotrifluoroethane, Freon 133a, is an organic compound with the chemical formula Chlorotrifluoroethane is also usually discharged as a by-product. At present, the waste gas of 2-chloro-1,1,1-trifluoroethane is generally treated by direct discharge, but direct discharge leads to serious damage to the ozone layer and has a great impact on the environment.

[0004] Chinese patent CN108774134A discloses a method for producing trifluoroethyl methacrylate, wherein trifluoroethanol, methacryloyl chloride and an inhibitor are reacted at 40-50°C for 12 hours, and then trifluoroethyl methacrylate is collected from the reaction product. Although production raw materials such as methacrylic acid and trifluoroethanol are relatively easy to obtain in the chemical industry, solid phosgene is used as a raw material, which is highly toxic and dangerous and presents a great safety risk. In addition, there are problems in terms of yield, inhibitor selection, waste disposal, etc.

[0005] U.S. Patent US2005085661A1 discloses the preparation of trifluoroethyl methacrylate by using methacrylic acid and trifluoroethanol as raw materials through the use of a pervaporation composite membrane. Although the conversion rate of trifluoroethyl methacrylate is improved, for industrial production, the preparation and maintenance costs of the pervaporation composite membrane in this method are relatively high, and there may be certain challenges in the selectivity and stability of the membrane, which is not conducive to the industrial preparation of trifluoroethyl methacrylate. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for synthesizing trifluoroethyl methacrylate, which utilizes waste gas chlorotrifluoroethane, has a high conversion rate, is environmentally friendly, and can realize industrial synthesis.

[0007] The trifluoroethyl methacrylate synthesized by the invention has high yield and high content.

[0008] The synthesis method of trifluoroethyl methacrylate of the present invention comprises the following steps: firstly, a solvent, methyl methacrylate, a catalyst and a polymerization inhibitor are mixed, the temperature is raised to 25-70°C, by-product chlorotrifluoroethane is introduced, the reaction is carried out for 4-6 hours after the addition is completed, and finally the reaction liquid is post-treated to obtain trifluoroethyl methacrylate. The optimal reaction temperature is in the range of 25-50°C.

[0009] The solvent is one of water, methanol, ethyl acetate, ether, tetrahydrofuran and dichloromethane. The amount of the solvent is not limited. The purpose of the solvent is to make the reaction proceed in the solution. As long as the reaction is completely carried out, the less the better to save materials.

[0010] The catalyst is one of triethylamine, trimethylamine and N,N-diethylaniline.

[0011] The polymerization inhibitor is 2,6-di-tert-butyl-p-cresol or p-methoxyphenol.

[0012] The post-treatment of the reaction solution is to remove the solvent by distillation.

[0013] The molar amount of the polymerization inhibitor is 2% mol to 3% mol of the molar amount of methyl methacrylate.

[0014] The molar amount of the catalyst is 2% mol to 3% mol of the molar amount of methyl methacrylate.

[0015] The content of the by-product chlorotrifluoroethane is ≥99.5wt%.

[0016] The rate of introducing the by-product chlorotrifluoroethane is 5.59 cm 3 / h, let in for 4-6h.

[0017] A trifluoroethyl methacrylate is synthesized by the synthesis method of trifluoroethyl methacrylate.

[0018] Specifically, the synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of solvent (one of water, methanol, ethyl acetate, ether, tetrahydrofuran, and dichloromethane), 25 g (0.25 mol) of methyl methacrylate, 2% mol-3% mol of inhibitor (2,6-di-tert-butyl-p-cresol or p-methoxyphenol), and 2% mol-3% mol of catalyst (one of triethylamine, trimethylamine, and N,N-diethylaniline) into a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 25°C-100°C, and heating at 5.59 cm 3 The by-product chlorotrifluoroethane gas is introduced at a rate of / h and the reaction is carried out for 4-6h. After the reaction is completed, the solvent is removed to obtain trifluoroethyl methacrylate.

[0019] The synthesis method of trifluoroethyl methacrylate of the present invention adopts a polar solvent as the solvent, which increases the charge property, makes it easier to generate a four-membered ring transition state, and improves the yield, wherein the best solvent is water. The present invention uses triethylamine, trimethylamine, and N,N-diethylaniline as catalysts, effectively improving the utilization rate of chlorotrifluoroethane. The reaction mechanism of the present invention is as follows: Figure 1 shown.

[0020] The present invention uses a catalyst such as triethylamine to polymerize chlorotrifluoroethane, which is a reversible reaction at a temperature of 25-70°C, has a good binding effect on chlorotrifluoroethane gas, effectively improves the utilization rate of chlorotrifluoroethane and improves the final yield. Its mechanism is as follows Figure 2 shown.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The method for synthesizing trifluoroethyl methacrylate of the present invention increases the yield of trifluoroethyl methacrylate to 98%, which is 80% compared with the yield of the traditional method, thus greatly improving the utilization rate of resources.

[0023] (2) Compared with the traditional synthesis method, the synthesis method of trifluoroethyl methacrylate of the present invention has more streamlined steps and the reaction time is shortened by about 50% compared with the 12 hours of the traditional method, thereby significantly improving the production efficiency.

[0024] (3) The synthesis method of trifluoroethyl methacrylate of the present invention generates significantly less waste than conventional synthesis methods, and significantly reduces the pressure on the environment.

[0025] (4) The purity of trifluoroethyl methacrylate prepared by the synthesis method of the present invention reaches more than 99%, which greatly improves the reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the reaction mechanism diagram of the present invention.

[0027] Figure 2 This is a reaction mechanism diagram of the polymerization of triethylamine with chlorotrifluoroethane using triethylamine as a catalyst in the present invention.

[0028] Figure 3 This is the gas chromatogram of trifluoroethyl methacrylate synthesized in Example 1. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments.

[0030] The raw materials and reagents used in the following examples and comparative examples are all commercially available products. The by-product chlorotrifluoroethane gas used below is a by-product of other production lines of the enterprise, and its content is ≥99.5wt%.

[0031] Example 1

[0032] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of water, 25 g of methyl methacrylate, 1.1 g (0.005 mol) of 2,6-di-tert-butyl-p-cresol, and 0.51 g of triethylamine to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 25° C. at 5.59 cm 3 The by-product chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was continued for 4h. After the reaction was completed, the mixture was allowed to stand, the liquid was separated, and the organic phase was filtered to obtain 41.33g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.854% by GC. Figure 3 The peak table is shown in Table 1, and the yield is calculated to be 98.33%.

[0033] Table 1 Peak table

[0034]

[0035] Example 2

[0036] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of methanol, 25 g of methyl methacrylate, 0.62 g (0.005 mol) of p-methoxyphenol, and 0.3 g of trimethylamine to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 50°C, and heating at 5.59 cm 3 Byproduct chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was carried out for 6h. After the reaction was completed, methanol was distilled off at 75°C to obtain 40.52g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.72% by GC analysis, and the calculated yield was 96.41%.

[0037] Example 3

[0038] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of ethyl acetate, 25 g of methyl methacrylate, 0.93 g (0.0075 mol) of methoxyphenol, and 1.12 g of N,N-diethylaniline into a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 70°C, and heating at 5.59 cm 3 The by-product chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was carried out for 6h. After the reaction was completed, ethyl acetate was distilled off at 80°C to obtain 39.52g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.81% by GC analysis. The calculated yield was 94.03%.

[0039] Example 4

[0040] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of ether, 25 g of methyl methacrylate, 1.65 g (0.0075 mol) of 2,6-di-tert-butyl-p-cresol, and 0.76 g of triethylamine to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 25°C, and heating at 5.59 cm 3 The by-product chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was carried out for 5h. After the reaction was completed, the ether was distilled off at 50°C to obtain 38.77g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.66% by GC analysis. The calculated yield was 92.24%.

[0041] Example 5

[0042] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g tetrahydrofuran, 25 g methyl methacrylate, 1.65 g (0.0075 mol) 2,6-di-tert-butyl-p-cresol, and 0.44 g trimethylamine into a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 25°C, and heating at 5.59 cm 3 The by-product chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was carried out for 5h. After the reaction was completed, tetrahydrofuran was distilled off at 80°C to obtain 39.18g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.59% by GC analysis, and the calculated yield was 93.21%.

[0043] Example 6

[0044] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of dichloromethane, 25 g of methyl methacrylate, 1.1 g (0.005 mol) of 2,6-di-tert-butyl-p-cresol, and 0.3 g of trimethylamine into a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 25°C, and heating at 5.59 cm 3 The by-product chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was carried out for 4h. After the reaction was completed, dichloromethane was distilled off at 50°C to obtain 38.99g of trifluoroethyl methacrylate. The GC detection showed that its content was 99.58%, and its calculated yield was 92.77%.

[0045] Example 7

[0046] The synthesis method of trifluoroethyl methacrylate comprises the following steps: adding 225 g of water, 25 g of methyl methacrylate, 0.62 g (0.005 mol) of p-methoxyphenol, and 1.12 g of N,N-diethylaniline to a four-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and then stirring and heating to 50°C, and heating at 5.59 cm3 The by-product chlorotrifluoroethane gas was introduced at a rate of / h and the reaction was carried out for 6h. After the reaction was completed, the mixture was allowed to stand, the liquids were separated, and the organic phase was filtered to obtain 40.82g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.61% by GC analysis, and the yield was calculated to be 97.12%.

[0047] Comparative Example 1

[0048] The other conditions were the same as those in Example 1, except that the catalyst was removed. After the reaction was completed, the reaction was allowed to stand for separation, and the organic phase was collected by filtration to obtain 34.93 g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.43% by GC analysis, and the yield was calculated to be 83.11%.

[0049] Comparative Example 2

[0050] The other conditions were the same as those in Example 1. The solvent was removed. After the reaction was completed, the organic phase was collected to obtain 36.11 g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.52% by GC analysis. The yield was calculated to be 85.91%.

[0051] Comparative Example 3

[0052] The other conditions were the same as those in Example 1, except that the polymerization inhibitor was removed. After the reaction was completed, the reaction was allowed to stand for separation, and the organic phase was collected by filtration to obtain 34.79 g of trifluoroethyl methacrylate. The content of trifluoroethyl methacrylate was 99.56% by GC, and the yield was calculated to be 82.78%.

Claims

1. A method for synthesizing trifluoroethyl methacrylate, characterized in that: The steps include: firstly, mixing a solvent, methyl methacrylate, a catalyst and a polymerization inhibitor, heating to 25-70° C., then introducing by-product chlorotrifluoroethane, reacting for 4-6 hours after the addition is completed, and finally post-treating the reaction solution to obtain trifluoroethyl methacrylate; The solvent is one of water, methanol, ethyl acetate, ether, tetrahydrofuran and dichloromethane; The catalyst is one of triethylamine, trimethylamine and N,N-diethylaniline; The polymerization inhibitor is 2,6-di-tert-butyl-p-cresol or p-methoxyphenol; The molar amount of the catalyst is 2% mol to 3% mol of the molar amount of methyl methacrylate.

2. The synthetic method of trifluoroethyl methacrylate according to claim 1, characterized in that: The post-treatment of the reaction solution is to remove the solvent by distillation.

3. The synthetic method of trifluoroethyl methacrylate according to claim 1, characterized in that: The molar amount of the polymerization inhibitor is 2% mol to 3% mol of the molar amount of methyl methacrylate.

4. The method for synthesizing trifluoroethyl methacrylate according to claim 1, wherein: The content of the by-product chlorotrifluoroethane is ≥99.5wt%.

5. The method for synthesizing trifluoroethyl methacrylate according to claim 1, characterized in that: The rate of introducing the by-product chlorotrifluoroethane is 5.59 cm 3 / h, let in for 4-6h.

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