Method for preparing cyclohexyl 1-ethyl acrylate by one-pot method

Abstract

The invention discloses a method for preparing cyclohexyl 1-ethyl acrylate by a one-pot method, cyclohexanone (compound III) is used as a raw material, the cyclohexyl 1-ethyl acrylate (compound I) is prepared by the one-pot method, active anhydride is generated in situ through acrylic acid and di-tert-butyl dicarbonate, then the active anhydride and an intermediate 1-ethyl cyclohexanol (compound II) are esterified, and the cyclohexyl 1-ethyl acrylate is obtained. The content of impurities generated in the reaction can be obviously reduced. The method is wide in application range and simple and efficient in process, the gas phase purity can reach 99.7%, the whole process is environmentally friendly, and the method is suitable for large-scale production and has good industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis, and more specifically to a one-pot method for preparing cyclohexyl 1-ethylacrylate. Background Technology

[0002] In micro-nano fabrication technologies such as microcontact printing and nanoimprint lithography, polymers like acrylics are widely used due to their excellent processing performance and tunable optical properties. However, conventional acrylic resins suffer from insufficient chemical corrosion resistance and low pattern fidelity, limiting their application in precision lithography. Cyclohexyl polyacrylate, on the other hand, possesses excellent solvent resistance and corrosion resistance, making it a novel photosensitive resin.

[0003] Currently, the preparation methods of polycyclohexyl acrylate monomer reported in domestic and foreign literature are mainly the following two, as shown below: one is to react cyclohexanone with Grignard reagent to obtain 1-ethylcyclohexanol, and then carry out esterification reaction with acryloyl chloride; the other is to directly condense the obtained 1-ethylcyclohexanol with acrylic acid in the presence of a condensing agent to form an ester.

[0004] , However, both routes have significant drawbacks: First, they both require the separation and purification of the intermediate 1-ethylcyclohexanol before proceeding to the next step of the reaction, which is a lengthy process; second, the post-reaction processing is cumbersome, and product loss is inevitable during the multi-step purification process, thus affecting the overall yield. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to overcome the shortcomings of the prior art and provide a one-pot method for preparing cyclohexyl 1-ethylacrylate.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows: On one hand, the present invention provides a one-pot method for preparing cyclohexyl 1-ethylacrylate, comprising the following steps: , S1: A mixture of compound III and tetrahydrofuran is added dropwise to a Grignard reagent solution in tetrahydrofuran under controlled temperature. After the addition is complete, the reaction is maintained at this temperature to obtain a tetrahydrofuran solution of compound II, which does not require separation. The Grignard reagent is... ; S2: After cooling the S1 reaction system, add pyridine catalyst, organic base, stabilizer and acrylic acid, and add a mixture of di-tert-butyl dicarbonate and tetrahydrofuran dropwise while maintaining the temperature and stirring the reaction. Wherein, the pyridine catalyst mentioned in S2 is 4-dimethylaminopyridine or 2,6-di-tert-butylpyridine, and the molar ratio of compound III to pyridine catalyst is in the range of 1:0.05~0.1; The stabilizer is p-methoxyphenol, and the molar ratio of compound III to stabilizer is in the range of 1:0.01~0.02; The organic base is triethylamine or N,N-diisopropylethylamine, and the molar ratio of compound III to organic base is in the range of 1:1.1~1.5; The molar ratio of compound III: acrylic acid: ditert-butyl dicarbonate is in the range of 1:1.1~1.5:1.2~1.5.

[0007] In some embodiments, the controlled temperature in S1 is 55~65℃; the controlled temperature in S2 is 50~65℃, and the reaction time is 4~12h.

[0008] In some embodiments, the Grignard reagent described in S1 The preparation method is as follows: under the protection of an inert gas, a mixture of bromoethane and tetrahydrofuran is added dropwise to a tetrahydrofuran solution of magnesium shavings and iodine granules, and then the mixture is heated and stirred to obtain a tetrahydrofuran solution of ethyl magnesium bromide. The mass ratio of magnesium shavings to bromoethane ranges from 1:4.8 to 5.2.

[0009] In some embodiments, the inert gas is nitrogen or argon, and the reaction temperature is 60~70°C.

[0010] In some embodiments, the post-processing steps of the reaction are as follows: after cooling the reaction solution of S2, saturated ammonium chloride aqueous solution is added to quench the reaction, ethyl acetate is added to extract the product, the organic phase is washed with brine, dried with anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain crude compound I; then the crude compound I is purified by reduced pressure distillation.

[0011] In some embodiments, the vacuum distillation purification process is as follows: in the presence of a polymerization inhibitor, the crude product of compound I is subjected to a pressure of 30-40 Pa, and the fraction at 50-60 °C is collected to obtain compound I.

[0012] In some embodiments, the polymerization inhibitor is p-methoxyphenol or hydroquinone.

[0013] The beneficial effects of this invention are as follows: This invention uses cyclohexanone (compound III) as a raw material to prepare 1-ethylcyclohexyl acrylate (compound I) via a one-pot process. This method involves the in-situ generation of an active anhydride from acrylic acid and di-tert-butyl dicarbonate, followed by esterification with the intermediate 1-ethylcyclohexanol (compound II), which significantly reduces the content of impurities generated during the reaction. This method has a wide range of applications; it can be used to synthesize a series of straight-chain alkyl cyclohexyl acrylates. This one-pot process is simple and efficient, uses highly safe acrylic acid with a gas-phase purity of up to 99.7%, and is environmentally friendly, suitable for large-scale production, and has good industrial application prospects. Detailed Implementation

[0014] Example 1: In a four-necked flask, add magnesium shavings (24.3 g, 1.0 mol, 1.3 eq.), one iodine grain, and 70 mL of tetrahydrofuran sequentially, and start mechanical stirring. In a constant-pressure dropping funnel, add bromoethane (117.2 g, 1.08 mol, 1.4 eq.) and 250 mL of tetrahydrofuran, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 26 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35°C). The reaction is exothermic; maintain the temperature at 60-66°C and continue adding bromoethane, completing the addition in approximately 2 hours. After the addition is complete, maintain the temperature at 60-70°C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain after stirring or standing. Separately dissolve 75.4 g (0.768 mol, 1.0 eq.) of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, and add it dropwise to the previously prepared reaction flask while maintaining the temperature at 55-60℃. The addition should be completed in approximately 2 hours, and the reaction should be maintained at this temperature for 1 hour after the addition is complete. After the system cooled to room temperature, 4-dimethylaminopyridine (4.7 g, 0.038 mol, 5% eq.), triethylamine (101.1 g, 1.0 mol, 1.3 eq.), p-methoxyphenol (0.95 g, 1% eq.), and acrylic acid (72 g, 1.0 mol, 1.3 eq.) were added. Separately, di-tert-butyl dicarbonate (234.7 g, 1.08 mol, 1.4 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant-pressure funnel and added dropwise to the previously prepared reaction flask. The temperature was controlled at 55-60℃, and the addition was completed in approximately 3 hours. After the addition was complete, the mixture was kept at this temperature for 6 hours.

[0015] After the reaction was completed, the system was cooled to 0-5℃, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500mL×3), the organic phase was washed with 20% brine (300 mL×2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 132.8 g of light brown viscous substance with GC purity of 87.6% and yield of 94.84%.

[0016] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of stabilizer was added to the receiving flask). The fraction distilled at 50-65 °C was collected at 30-40 Pa to give 100.7 g of colorless liquid product with a GC purity of 99.35% and a yield of 71.92%.

[0017] Example 2: Add magnesium shavings (25.1 g, 1.03 mol, 1.3 eq.), one iodine grain, and 70 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (121.3 g, 1.11 mol, 1.4 eq.) and 250 mL of tetrahydrofuran to a constant-pressure dropping funnel, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 26 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35 °C), controlling the temperature at 60-66 °C, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70 °C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 78 g (0.795 mol, 1.0 eq.) of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 55-60 °C, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour after the addition is complete. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (7.6 g, 0.04 mol, 5% eq.), triethylamine (104.6 g, 1.03 mol, 1.3 eq.), p-methoxyphenol (0.99 g, 1% eq.), and acrylic acid (74.5 g, 1.03 mol, 1.3 eq.) were added. Separately, di-tert-butyl dicarbonate (242.8 g, 1.11 mol, 1.4 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant pressure funnel and added dropwise to the previously prepared reaction flask. The temperature was controlled at 55-60 °C, and the addition was completed in approximately 3 hours. After the addition was complete, the mixture was kept at this temperature for 6 hours.

[0018] After the reaction was completed, the system was cooled to 0-5 °C, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500 mL × 3), the organic phase was washed with 20% brine (300 mL × 2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 139.2 g of light brown viscous substance with GC purity of 90.2% and yield of 96.10%.

[0019] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of p-methoxyphenol was added to the receiving flask). The fraction distilled at 50-65 °C was collected at 30-40 Pa to give 107.5 g of colorless liquid product with a GC purity of 99.5% and a yield of 74.21%.

[0020] Example 3: Add magnesium shavings (25.1 g, 1.03 mol, 1.3 eq.), one iodine grain, and 70 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (121.3 g, 1.11 mol, 1.4 eq.) and 250 mL of tetrahydrofuran to a constant-pressure dropping funnel, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 26 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35 °C), controlling the temperature at 60-66 °C, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70 °C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 78 g (0.795 mol, 1.0 eq.) of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 55-60 °C, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour afterward. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (7.6 g, 0.04 mol, 5% eq.), triethylamine (120.6 g, 1.19 mol, 1.5 eq.), p-methoxyphenol (0.99 g, 1% eq.), and acrylic acid (85.9 g, 1.19 mol, 1.5 eq.) were added. Separately, di-tert-butyl dicarbonate (260.2 g, 1.19 mol, 1.5 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant pressure funnel and added dropwise to the previously prepared reaction flask. The temperature was controlled at 55-60 °C, and the addition was completed in approximately 3 hours. After the addition was complete, the mixture was kept at this temperature for 6 hours.

[0021] After the reaction was completed, the system was cooled to 0-5 °C, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500 mL × 3), the organic phase was washed with 20% brine (300 mL × 2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 137.2 g of light brown viscous substance with GC purity of 90.6% and yield of 94.72%.

[0022] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of p-methoxyphenol was added to the receiving flask). The fraction distilled at 50-65 °C was collected at 30-40 Pa to give 106.2 g of colorless liquid product with a GC purity of 99.7% and a yield of 73.32%.

[0023] Example 4: Add magnesium shavings (24.3 g, 1.0 mol, 1.3 eq.), one iodine grain, and 70 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (117.2 g, 1.08 mol, 1.4 eq.) and 250 mL of tetrahydrofuran to a constant-pressure dropping funnel, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 26 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35 °C), controlling the temperature at 60-66 °C, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70 °C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 75.4 g (0.769 mol, 1.0 eq.) of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 55-60 °C, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour after the addition is complete. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (7.4 g, 0.04 mol, 5% eq.), triethylamine (85.5 g, 0.845 mol, 1.1 eq.), p-methoxyphenol (0.95 g, 1% eq.), and acrylic acid (61.0 g, 0.845 mol, 1.1 eq.) were added. Separately, di-tert-butyl dicarbonate (201.2 g, 0.922 mol, 1.2 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant pressure funnel and added dropwise to the previous reaction flask while maintaining the temperature at 55-60 °C. The addition was completed in about 3 h, and the mixture was kept at this temperature for 6 h after the addition was completed.

[0024] After the reaction was completed, the system was cooled to 0-5 °C, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500 mL × 3), the organic phase was washed with 20% brine (300 mL × 2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 128.2 g of light brown viscous substance with GC purity of 84.1% and yield of 91.56%.

[0025] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of p-methoxyphenol was added to the receiving flask). The fraction collected at 50-65 °C was collected at 30-40 Pa to give 98.5 g of colorless liquid product with a GC purity of 99.1% and a yield of 70.35%.

[0026] Example 5: Add magnesium shavings (24.3 g, 1.0 mol, 1.3 eq.), one iodine grain, and 70 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (117.2 g, 1.08 mol, 1.4 eq.) and 250 mL of tetrahydrofuran to a constant-pressure dropping funnel, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 26 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35 °C), controlling the temperature at 60-66 °C, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70 °C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 75.4 g (0.769 mol, 1.0 eq.) of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 60-65 °C, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour afterward. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (7.4 g, 0.04 mol, 5% eq.), triethylamine (101.1 g, 1.0 mol, 1.3 eq.), p-methoxyphenol (0.94 g, 1% eq.), and acrylic acid (72.0 g, 1.0 mol, 1.3 eq.) were added. Separately, di-tert-butyl dicarbonate (234.7 g, 1.08 mol, 1.4 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant-pressure funnel, and the temperature was controlled at 50-55 °C. The solution was added dropwise to the previously prepared reaction flask. The addition was completed in approximately 3 hours, and the mixture was kept at this temperature for 12 hours after the addition was finished.

[0027] After the reaction was completed, the system was cooled to 0-5 °C, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500 mL × 3), the organic phase was washed with 20% brine (300 mL × 2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 129.3 g of light brown viscous substance with GC purity of 88.6% and yield of 92.34%.

[0028] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of p-methoxyphenol was added to the receiving flask). The fraction distilled at 50-65°C was collected at 30-40 Pa to give 95.4 g of colorless liquid product with a GC purity of 99.0% and a yield of 68.13%.

[0029] Example 6: Add magnesium shavings (31.6 g, 1.3 mol, 1.3 eq.), one iodine grain, and 100 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (152.5 g, 1.4 mol, 1.4 eq.) and 300 mL of tetrahydrofuran to a constant-pressure dropping funnel, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 31 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35 °C), controlling the temperature at 60-66 °C, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70 °C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 98.1 g, 1.0 mol, 1.0 eq. of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 55-60℃, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour after the addition is complete. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (19.1 g, 0.1 mol, 10% eq.), triethylamine (131.5 g, 1.3 mol, 1.3 eq.), p-methoxyphenol (2.5 g, 2.0% eq.), and acrylic acid (93.7 g, 1.3 mol, 1.3 eq.) were added. Separately, di-tert-butyl dicarbonate (305.4 g, 1.4 mol, 1.4 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant pressure funnel, and the temperature was controlled at 55-65 °C. This solution was added dropwise to the previously prepared reaction flask. The addition was completed in approximately 3 hours, and the mixture was kept at this temperature for 4 hours after the addition was finished.

[0030] After the reaction was completed, the system was cooled to 0-5 °C, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500 mL × 3), the organic phase was washed with 20% brine (300 mL × 2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 177.1 g of light brown viscous substance with GC purity of 90.8% and yield of 97.21%.

[0031] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of p-methoxyphenol was added to the receiving flask). The fraction collected at 50-65 °C was collected at 30-40 Pa to give 140.0 g of colorless liquid product with a GC purity of 99.4% and a yield of 76.85%.

[0032] Example 7: Add magnesium shavings (21.4 g, 0.88 mol, 1.1 eq.), one iodine grain, and 60 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (104.6 g, 0.96 mol, 1.2 eq.) and 230 mL of tetrahydrofuran to a constant-pressure dropping funnel, and purge the reaction system with nitrogen. Under nitrogen protection, initiate the reaction by adding approximately 25 mL of bromoethane solution (approximately 7-8%) at room temperature (30-35 °C), controlling the temperature at 60-66 °C, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70 °C for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 78.5 g (0.8 mol, 1.0 eq.) of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 55-60 °C, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour afterward. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (7.65 g, 0.04 mol, 5% eq.), triethylamine (105.2 g, 1.04 mol, 1.3 eq.), p-methoxyphenol (0.99 g, 1% eq.), and acrylic acid (74.9 g, 1.04 mol, 1.3 eq.) were added. Separately, di-tert-butyl dicarbonate (244.4 g, 1.12 mol, 1.4 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant pressure funnel, and the temperature was controlled at 50-55 °C. This solution was added dropwise to the previously prepared reaction flask. The addition was completed in approximately 3 hours, and the mixture was kept at this temperature for 12 hours after the addition was finished.

[0033] After the reaction was completed, the system was cooled to 0-5℃, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500 mL × 3), the organic phase was washed with 20% brine (300 mL × 2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 132.7 g of light brown viscous substance with GC purity of 83.4% and yield of 91.03%.

[0034] The crude product was distilled under reduced pressure using an oil pump (1 g of p-methoxyphenol was added to the distillation flask, connected to a 20 cm column, and 0.1 g of p-methoxyphenol was added to the receiving flask). The fraction distilled at 50-65℃ was collected at 30-40 Pa to give 96.4 g of colorless liquid product with a GC purity of 99.1% and a yield of 66.13%.

[0035] Example 8: Add magnesium shavings (31.6 g, 1.3 mol, 1.3 eq.), one iodine grain, and 100 mL of tetrahydrofuran to a four-necked flask and start mechanical stirring. Add bromoethane (152.5 g, 1.4 mol, 1.4 eq.) and 300 mL of tetrahydrofuran to a constant-pressure dropping funnel, purging the reaction system with argon. Under argon protection, initiate the reaction by adding approximately 31 mL of bromoethane solution (approximately 7-8%) dropwise at room temperature (30-35℃), controlling the temperature at 60-66℃, and continue adding bromoethane dropwise for approximately 2 hours. After the addition is complete, maintain the temperature at 60-70℃ for approximately 1 hour. The reaction is considered complete when no magnesium shavings remain under stirring or stillness. Separately dissolve 98.1 g, 1.0 mol, 1.0 eq. of cyclohexanone in 100 mL of tetrahydrofuran in a constant pressure funnel, maintaining the temperature at 55-60℃, and add it dropwise to the previously prepared reaction flask. The addition should be completed in approximately 2 hours, and the mixture should be kept at this temperature for 1 hour after the addition is complete. The system was cooled to room temperature, and then 2,6-di-tert-butylpyridine (19.1 g, 0.1 mol, 10% eq.), N,N-diisopropylethylamine (168.0 g, 1.3 mol, 1.3 eq.), p-methoxyphenol (2.5 g, 2.0% eq.), and acrylic acid (93.7 g, 1.3 mol, 1.3 eq.) were added. Separately, di-tert-butyl dicarbonate (305.4 g, 1.4 mol, 1.4 eq.) was dissolved in 100 mL of tetrahydrofuran in a constant-pressure funnel, and the temperature was controlled at 55-65℃. This solution was added dropwise to the previously prepared reaction flask. The addition was completed in approximately 3 hours, and the mixture was kept at this temperature for 4 hours after the addition was finished.

[0036] After the reaction was completed, the system was cooled to 0-5℃, the reaction was quenched with saturated ammonium chloride aqueous solution, the product was extracted with ethyl acetate (500mL×3), the organic phase was washed with 20% brine (300 mL×2), dried with anhydrous sodium sulfate, filtered, and concentrated to obtain 175.6 g of light brown viscous substance with GC purity of 91.8% and yield of 96.39%.

[0037] The crude product was distilled under reduced pressure using an oil pump (1 g of hydroquinone was added to the distillation flask, connected to a 20 cm column, and 0.1 g of hydroquinone was added to the receiving flask). The fraction distilled at 50-65 °C was collected at 30-40 Pa to give 141.2 g of colorless liquid product with a GC purity of 99.6% and a yield of 77.51%.

[0038] The embodiments described above are merely optional embodiments of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing cyclohexyl 1-ethylacrylate in a one-pot process, characterized in that, Includes the following steps: ， S1: A mixture of compound III and tetrahydrofuran is added dropwise to a Grignard reagent solution in tetrahydrofuran under controlled temperature. After the addition is complete, the reaction is maintained at this temperature to obtain a tetrahydrofuran solution of compound II, which does not require separation. The Grignard reagent is... ; S2: After cooling the S1 reaction system, add pyridine catalyst, organic base, stabilizer and acrylic acid, and add a mixture of di-tert-butyl dicarbonate and tetrahydrofuran dropwise while maintaining the temperature and stirring the reaction. Wherein, the pyridine catalyst mentioned in S2 is 4-dimethylaminopyridine or 2,6-di-tert-butylpyridine, and the molar ratio of compound III to pyridine catalyst is in the range of 1:0.05~0.1; The stabilizer is p-methoxyphenol, and the molar ratio of compound III to stabilizer is in the range of 1:0.01~0.02; The organic base is triethylamine or N,N-diisopropylethylamine, and the molar ratio of compound III to organic base is in the range of 1:1.1~1.5; The molar ratio of compound III: acrylic acid: ditert-butyl dicarbonate is in the range of 1:1.1~1.5:1.2~1.

5.

2. The method for preparing cyclohexyl 1-ethylacrylate in a one-pot process according to claim 1, characterized in that, The controlled temperature in S1 is 55~65℃; the controlled temperature in S2 is 50~65℃, and the reaction time is 4~12h.

3. The method for preparing cyclohexyl 1-ethylacrylate in a one-pot process according to claim 1, characterized in that, Grignard reagents described in S1 The preparation method is as follows: under the protection of an inert gas, a mixture of bromoethane and tetrahydrofuran is added dropwise to a tetrahydrofuran solution of magnesium shavings and iodine granules, and then the mixture is heated and stirred to obtain a tetrahydrofuran solution of ethyl magnesium bromide. The mass ratio of magnesium shavings to bromoethane ranges from 1:4.8 to 5.

2.

4. The method for preparing cyclohexyl 1-ethylacrylate in a one-pot process according to claim 3, characterized in that, The inert gas is nitrogen or argon, and the reaction temperature is 60~70℃.

5. The method for preparing cyclohexyl 1-ethylacrylate in a one-pot process according to claim 1, characterized in that, The post-processing steps of the reaction are as follows: after cooling the reaction solution of S2, saturated ammonium chloride aqueous solution is added to quench the reaction, ethyl acetate is added to extract the product, the organic phase is washed with brine, dried with anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to obtain crude compound I; then the crude compound I is purified by reduced pressure distillation.

6. The method for preparing cyclohexyl 1-ethylacrylate in a one-pot process according to claim 5, characterized in that, The vacuum distillation purification process is as follows: in the presence of a polymerization inhibitor, the crude product of compound I is subjected to a pressure of 30-40 Pa, and the fraction at 50-60 °C is collected to obtain compound I.

7. The method for preparing cyclohexyl 1-ethylacrylate in a one-pot process according to claim 6, characterized in that, The polymerization inhibitor is p-methoxyphenol or hydroquinone.

Images