A method for producing acetone glyceryl methacrylate by transesterification

Abstract

A method for producing acetone glyceryl methacrylate via transesterification involves adding methyl methacrylate and glyceryl acetone, a polymerization inhibitor tetramethylpiperidine nitroxide radical triphosphite, and a catalyst calcium acetylacetonate or zinc acetylacetonate, to an esterification reactor. The reactor is stirred and heated to 103℃-107℃ for 3-6 hours. Heating is then stopped. By controlling the reflux ratio of the reflux device at the top of the esterification reactor, the temperature inside the reactor is maintained at 121-131.5℃, and the temperature at the top of the distillation column is maintained at 92-96℃. After esterification, vacuum distillation is performed to obtain acetone glyceryl methacrylate. The advantages are: continuous reaction, simple operation, use of an organotin catalyst that does not contain heavy metal tin, and a final product yield of 94.5%-96% with a purity of over 97%, an acid value of 0.001 mg / g KOH, and a platinum-cobalt color of 5-20.

Description

Technical Field

[0001] This invention relates to a method for producing acetone glyceryl methacrylate by transesterification. Background Technology

[0002] Acetone glycerol methacrylate possesses high reactivity due to its bifunctional nature, consisting of unsaturated double bonds and epoxy groups. The unsaturated double bonds can undergo polymerization, while the epoxy groups can undergo ring-opening reactions to form hydroxy isocyanate groups (-NCO) for cross-linking. It exhibits excellent weather resistance, chemical resistance, and water resistance, making it a superior reactive monomer widely used in photoresists, inks, coatings, and adhesives. With the development of industrial technology, the requirements for the content of acetone glycerol methacrylate have increased. Furthermore, acetone glycerol methacrylate can be used as a reactive diluent, cross-linking with isocyanate groups (-NCO), and can also undergo polymerization and curing. Therefore, the requirement for acetone glycerol methacrylate to be free of volatile organic compounds (VOCs) and organotin compounds, thus reducing VOC emissions, has significant application value.

[0003] Currently, acetone glyceryl methacrylate is mainly obtained through the alcohol-acid process or transesterification, using organotin catalysts, such as those disclosed in CN 113831317 A ("A method for producing acetone glyceryl methacrylate by transesterification"), CN106588864 A ("Cyclohexyldioxopentanol methyl methacrylate monomer and its application"), and CN106588860 A ("Dimethyldioxopentanol methyl methacrylate monomer and its application"). These catalysts dissolve in methyl methacrylate and acetone glyceryl methacrylate, resulting in organotin content in the product during distillation separation. This fails to meet the requirements of the application fields or generates acidic wastewater, causing environmental problems. Furthermore, the acid value, color, and metal content of products obtained through existing technologies do not meet the requirements, limiting their application and failing to meet industrial requirements.

[0004] CN 110272408 A discloses a method for preparing a photocurable agent, dimethyldioxopentanol methacrylate. This method uses methacrylic acid and acetone glycerol in a molar ratio of 0.9:1-1.5:1 as raw materials, adds a solvent, uses 4-dimethylaminopyridine and 1-hydroxybenzotriazole as catalysts, and uses TEMPO tetramethylpiperidine nitride, hydroquinone, p-hydroxyanisole, and phenothiazine as polymerization inhibitors. A dehydrating agent is also added to carry out the reaction, yielding the product. This preparation method requires the use of solvents and dehydrating agents, and involves water washing, making the operation cumbersome, generating wastewater that pollutes the environment, and resulting in a high product yield of only 77%, indicating a low yield. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for producing acetone glyceryl methacrylate by transesterification that is highly efficient, fast, low-pollution, produces high-quality products with good acid value, color and metal content.

[0006] The technical solution of this invention is:

[0007] A method for producing acetone glyceryl methacrylate via transesterification, comprising the following specific steps:

[0008] The raw material methyl methacrylate and glycerol acetone, the polymerization inhibitor tetramethylpiperidine nitroxide radical triphosphite, and the catalyst calcium acetylacetonate or zinc acetylacetonate are added together to an esterification reactor equipped with a stirrer, a distillation column, a top condenser, and a reflux ratio controller. The molar ratio of methyl methacrylate to glycerol acetone is (2.6-3.1):1. The amount of polymerization inhibitor added is 0.303%-0.454% of the mass of glycerol acetone, and the amount of catalyst added is 2.5%-3.5% of the mass of glycerol acetone. The stirrer is started to circulate air through the esterification reactor. The reaction is carried out by electric heating, with the temperature inside the esterification reactor reaching 103℃-107℃. After 3-6 hours of reaction, heating is stopped. The reflux ratio of the reflux device at the top of the esterification reactor is controlled at (8-12):2 to keep the temperature inside the esterification reactor at 121-131.5℃ and the temperature at the top of the distillation column at 92-96℃, thus completing the esterification. The esterification reactor is then cooled to 43℃-54℃ using circulating condensate. Vacuum distillation is then performed to recover unreacted methyl methacrylate and glyceryl acetone from the raw materials. The vacuum level is increased, and vacuum distillation continues to obtain glyceryl acetone methacrylate.

[0009] Furthermore, when recovering excess raw materials such as methyl methacrylate and acetone glycerol by vacuum distillation, the vacuum degree is controlled at 10 kPa-13 kPa, and the top temperature of the distillation column is 40-80℃.

[0010] Furthermore, when collecting acetone glyceryl methacrylate by vacuum distillation, the vacuum level is controlled at 1 kPa-3 kPa, and the top temperature of the distillation column is 120℃-123℃.

[0011] Furthermore, the obtained acetone glyceryl methacrylate product was analyzed by gas chromatography and found to have a purity of 97%.

[0012] Furthermore, the mass content of the acetone glycerol is ≥96.4%.

[0013] Furthermore, during the esterification process, an azeotropic mixture of methyl methacrylate and methanol is separated from the top of the distillation column.

[0014] The beneficial effects of this invention are:

[0015] Using a neutral organic calcium or organic zinc catalyst and a highly efficient polymerization inhibitor, tetramethylpiperidine nitroxide radical triphosphite, without the use of organotin catalysts and containing no heavy metal tin, and with a small amount of catalyst, combined with a highly efficient polymerization inhibitor, the entire reaction and distillation process is stable and uses only one set of equipment. The reaction is continuous and the operation is simple. The final product yield obtained by vacuum distillation is as high as 94.5%-96%, with a purity of over 97%, an acid value of 0.001 mg / g KOH, and a platinum-cobalt color of 5-20. During the esterification process, the azeotrope separated is a mixture of methyl methacrylate and methanol. The excess methyl methacrylate is distilled off under reduced pressure at a temperature below 54°C and reused. The vacuum degree is increased and the temperature is raised for further distillation to obtain the product. After completion, the residue is released from the reactor and fed into the next batch for production. It has the characteristics of high production efficiency, fast speed, low pollution, and excellent product performance. Attached Figure Description

[0016] Figure 1 This is a gas chromatogram of acetone glycerol, the raw material in an embodiment of the present invention;

[0017] Figure 2 This is the gas chromatogram of acetone glycerol methacrylate according to the present invention (corresponding to Example 1);

[0018] Figure 3 This is the gas chromatogram of acetone glycerol methacrylate of the present invention (corresponding to Example 3);

[0019] Figure 4 This is the gas chromatogram of acetone glycerol methacrylate of the present invention (counterpart 1);

[0020] Figure 5 This is the gas chromatogram of acetone glycerol methacrylate of the present invention (corresponding example 3). Detailed Implementation

[0021] Example 1

[0022] Step 1: Esterification reaction

[0023] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 310.4 g of methyl methacrylate, 132.15 g of glyceryl acetone, 0.45 g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 4.23 g of calcium acetylacetone catalyst were added in a single batch.

[0024] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0025] Start the agitator to stir the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 103°C to start the reaction. After 4 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 121°C, and the temperature at the top of the distillation column is 94°C. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0026] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0027] Cool down to 43℃, turn on the vacuum system to control the vacuum degree to 10kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 40-70℃.

[0028] Step 3: Collect acetone glyceryl methacrylate by vacuum distillation

[0029] The esterification solution after the recovery of methyl methacrylate and glyceryl acetone was further heated, and the vacuum degree was controlled at 1 kPa. The distillation column top temperature was maintained at 120-121℃. 189.6 g of glyceryl acetone methacrylate (theoretical 200.23 g) was obtained, with a yield of 94.69%. Gas chromatography analysis showed a purity of 97.1%. The gas chromatogram of glyceryl acetone methacrylate is shown below. Figure 2 The retention time shown is 9.988 minutes, acid value is 0.001 mg / g KOH, platinum-cobalt color is 20, and moisture content is 0.069%.

[0030] Example 2

[0031] Step 1: Esterification reaction

[0032] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 260.32 g of methyl methacrylate, 132.15 g of acetone glycerol, 0.6 g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 4.62 g of calcium acetylacetonate catalyst were added in a single batch.

[0033] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0034] Start the agitator to mix the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 107°C to start the reaction. After 6 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the azeotropic mixture of methyl methacrylate and methanol is separated from the top of the distillation column during the esterification process. The temperature inside the esterification reactor is 131.5°C, and the temperature at the top of the distillation column is 92°C. The esterification reaction ends.

[0035] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0036] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 13kPa, and keep the top temperature of the distillation column at 50-80℃ to recover methyl methacrylate and acetone glycerol.

[0037] Step 3: Collect acetone glyceryl methacrylate by vacuum distillation

[0038] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 3 kPa. The distillation column top temperature was 122-123℃. 190 g of glyceryl acetone methacrylate (theoretical yield 200.23 g) was obtained, with a yield of 94.9%. Gas chromatography analysis showed a purity of 97.12%, an acid value of 0.001 mg / g KOH, a platinum-cobalt color of 10, and a moisture content of 0.04%.

[0039] Example 3

[0040] Step 1: Esterification reaction

[0041] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 300.36 g of methyl methacrylate, 132.15 g of glyceryl acetone, 0.4 g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 3.31 g of calcium acetylacetonate catalyst were added in a single batch.

[0042] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0043] Start the agitator to mix the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106℃ to start the reaction. After 3 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 125.3℃, and the temperature at the top of the distillation column is 96℃. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0044] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0045] Cool down to 50℃, turn on the vacuum system to control the vacuum degree to 12kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 45-76℃.

[0046] Step 3: Collect acetone glyceryl methacrylate by vacuum distillation

[0047] The esterification solution after the recovery of methyl methacrylate and glyceryl acetone was further heated, and the vacuum degree was controlled at 2 kPa. The distillation column top temperature was maintained at 121-122℃. 190.3 g of glyceryl acetone methacrylate (theoretical yield 200.23 g) was obtained, with a yield of 95%. Gas chromatography analysis showed a purity of 97.2%. The gas chromatogram of glyceryl acetone methacrylate is shown below. Figure 3 The retention time shown is 10.251 minutes, the acid value is 0.001 mg / g KOH, the platinum-cobalt color is 10, and the moisture content is 0.05%.

[0048] Example 4

[0049] Step 1: Esterification reaction

[0050] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 336g of methyl methacrylate, 158.58g of acetone glycerol, 0.64g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 4.75g of calcium acetylacetone catalyst were added in a single batch.

[0051] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0052] Start the agitator to stir the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 105℃ to start the reaction. After 5 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 128.6℃, and the temperature at the top of the distillation column is 94℃. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0053] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0054] Cool down to 48℃, turn on the vacuum system to control the vacuum level at 11kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 46-78℃.

[0055] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0056] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 2.5 kPa. The distillation column top temperature was 122-122.5℃. 229 g of glyceryl acetone methacrylate (theoretical yield 240.28 g) was obtained, with a yield of 95.3%. The purity was 97.1% by gas chromatography analysis, the acid value was 0.001 mg / g KOH, the platinum-cobalt color was 15, and the moisture content was 0.06%.

[0057] Example 5

[0058] Step 1: Esterification reaction

[0059] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 309g of methyl methacrylate, 132g of acetone glycerol, 0.56g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 3.96g of zinc acetylacetone catalyst were added in one step.

[0060] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0061] Start the agitator to stir the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106°C to start the reaction. After 3 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 125°C, and the temperature at the top of the distillation column is 94°C. The esterification reaction ends. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0062] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0063] Cool down to 52℃, turn on the vacuum system to control the vacuum level at 11.5kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 50-74℃.

[0064] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0065] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 2.6 kPa. The distillation column top temperature was 122-122.8℃. 189 g of glyceryl acetone methacrylate (theoretical 200 g) was obtained, with a yield of 94.5%. The purity was 97% by gas chromatography analysis, the acid value was 0.001 mg / g KOH, the platinum-cobalt color was 18, and the moisture content was 0.06%.

[0066] Example 6

[0067] Step 1: Esterification reaction

[0068] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 363g of methyl methacrylate, 160g of acetone glycerol, 0.61g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 4.64g of zinc acetylacetone catalyst were added in one step.

[0069] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0070] Start the agitator to stir the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106.6℃ to start the reaction. After 5 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 131℃, and the temperature at the top of the distillation column is 93℃. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0071] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0072] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 10.5kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 50-72℃.

[0073] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0074] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 1.6 kPa. The distillation column top temperature was 121-122℃. 229.8 g of glyceryl acetone methacrylate (theoretical yield 242.43 g) was obtained, with a yield of 94.8%. Gas chromatography analysis showed a purity of 97.01%, an acid value of 0.001 mg / g KOH, a platinum-cobalt color of 15, and a moisture content of 0.055%.

[0075] Example 7

[0076] Step 1: Esterification reaction

[0077] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 310g of recovered methyl methacrylate, 132g of acetone glycerol, 0.56g of polymerization inhibitor tetramethylpiperidine nitroxide free radical phosphite triester, and 4.62g of calcium acetylacetone catalyst were added in a single batch.

[0078] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0079] Start the agitator to mix the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 107°C to start the reaction. After 6 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 129.6°C, and the temperature at the top of the distillation column is 96°C. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0080] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0081] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 11.8kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 52-75℃.

[0082] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0083] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 1.3 kPa. The distillation column top temperature was 121.8-122.5℃. 192 g of glyceryl acetone methacrylate (theoretical 200 g) was obtained, with a yield of 96%. The purity was 97% by gas chromatography analysis, with an acid value of 0.001 mg / g KOH, a platinum-cobalt color of 5, and a moisture content of 0.075%.

[0084] Comparative Example 1 used dioctyltin oxide as the catalyst, and the rest was the same as in Example 6.

[0085] Step 1: Esterification reaction

[0086] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 363g of methyl methacrylate, 160g of 96.42% acetone glycerol, 0.61g of tetramethylpiperidine nitroxide free radical phosphite as a polymerization inhibitor, and 4.64g of dioctyl tin oxide catalyst were added in one step.

[0087] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0088] Start the agitator to mix the materials in the reactor evenly. Use an oil bath to heat the esterification reactor to a temperature of 106.6℃ to start the reaction. After 5 hours, if the reaction is not complete, continue the reaction for another 5 hours to complete the esterification reaction. Stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature in the esterification reactor is 131℃. The temperature at the top of the distillation column is 93℃, and the esterification reaction is completed. During the esterification process, a mixture of methyl methacrylate and methanol, an azeotrope, is separated from the top of the distillation column.

[0089] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation.

[0090] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 10.5kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 50-72℃.

[0091] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0092] The esterification solution after the recovery of methyl methacrylate and glyceryl acetone was further heated, and the vacuum degree was controlled at 1.6 kPa. The distillation column top temperature was maintained at 121-122℃. 189.9 g of glyceryl acetone methacrylate (theoretical yield 242.43 g) was obtained, with a yield of 78.3%. Gas chromatography analysis showed a purity of 95.07%. The gas chromatogram of glyceryl acetone methacrylate is shown below. Figure 4 The retention time shown was 10.192 minutes, the acid value was 0.003 mg / g KOH, the platinum-cobalt color was 35, and the moisture content was 0.08%.

[0093] Comparative Example 2 used a dibutyltin dilaurate catalyst instead of the catalyst, otherwise it was the same as in Example 6.

[0094] Step 1: Esterification reaction

[0095] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 363g of methyl methacrylate, 160g of acetone glycerol, 0.61g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 4.64g of dibutyltin dilaurate catalyst were added in one step.

[0096] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0097] Start the agitator to mix the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106.6℃ to start the reaction. After 5 hours of reaction, if the reaction is not complete, continue the reaction for another 3 hours to complete the esterification reaction. Stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 131℃, and the temperature at the top of the distillation column is 93℃. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0098] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation.

[0099] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 10.5kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 50-72℃.

[0100] Step 3: Collecting acetone glycerol methacrylate by vacuum distillation. After recovering methyl methacrylate and acetone glycerol, the esterified liquid is heated further, and the vacuum degree is controlled at 3 kPa. The distillation column top temperature is 121-122℃. 213.85 g of acetone methacrylate (theoretical 242.43 g) is obtained, with a yield of 88.3%. Gas chromatography analysis shows a purity of 96.3%, an acid value of 0.005 mg / g KOH, a platinum-cobalt color of 35, and a moisture content of 0.085%.

[0101] Comparative Example 3 used tetrabutyl titanate catalyst instead of catalyst, otherwise the same as in Example 6.

[0102] Step 1: Esterification reaction

[0103] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 363g of methyl methacrylate, 160g of acetone glycerol, 0.61g of tetramethylpiperidine nitroxide free radical phosphite (polymerization inhibitor), and 4.64g of tetrabutyl titanate catalyst were added in one step.

[0104] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0105] Start the agitator to mix the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106.6℃ to start the reaction. After 5 hours of reaction, if the reaction is not complete, continue the reaction for another 11 hours to complete the esterification reaction. Stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 131℃, and the temperature at the top of the distillation column is 93℃. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0106] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0107] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 10.5kPa, and recover methyl methacrylate and acetone glycerol at the top of the distillation column at 50-72℃.

[0108] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0109] The esterification solution after the recovery of methyl methacrylate and glycerol acetone was further heated, and the vacuum degree was controlled at 3 kPa. The top temperature was 121-122℃. 210.9 g of glycerol acetone methacrylate (theoretical yield 242.43 g) was obtained by distillation, with a yield of 87%. Gas chromatography analysis showed a purity of 95.6%. The gas chromatogram of glycerol acetone methacrylate is shown below. Figure 5 The retention time shown was 10.278 minutes, the acid value was 0.006 mg / g KOH, the platinum-cobalt color was 40, and the moisture content was 0.09%.

[0110] Comparative Example 4 uses TEMPO tetramethylpiperidine oxynitride as the polymerization inhibitor and dioctyltin oxide as the catalyst, otherwise it is the same as in Example 6.

[0111] Step 1: Esterification reaction

[0112] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 363g of methyl methacrylate, 160g of acetone glycerol, 0.61g of polymerization inhibitor TEMPO tetramethylpiperidine N-oxide, and 4.64g of dioctyltin oxide catalyst were added in one step.

[0113] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0114] Start the agitator to mix the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106.6℃ to start the reaction. If the reaction is not complete after 5 hours, continue the reaction for another 5 hours to complete the esterification reaction. Stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 131℃, and the temperature at the top of the distillation column is 93℃. The esterification reaction is over. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0115] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0116] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 10.5kPa, and maintain the top temperature of the distillation column at 50-72℃ to recover methyl methacrylate and acetone glycerol.

[0117] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0118] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 1.6 kPa. The distillation column top temperature was 121-122℃. 181.8 g of glyceryl acetone methacrylate (theoretical 242.43 g) was obtained, with a yield of 75%. The purity was 96.3% by gas chromatography, the acid value was 0.005 mg / g KOH, the platinum-cobalt color was 50, and the moisture content was 0.08%.

[0119] Comparative Example 5 uses TEMPO tetramethylpiperidine oxynitride as the polymerization inhibitor, otherwise it is the same as in Example 6.

[0120] Step 1: Esterification reaction

[0121] In a 1L esterification reactor equipped with an automatic temperature-controlled electric heating oil bath with cooling coils, and containing a stirrer, thermocouple, pressure display instrument, distillation column, reflux ratio controller, condenser, vacuum device, and receiving bottle, 363g of methyl methacrylate, 160g of acetone glycerol, 0.61g of polymerization inhibitor TEMPO tetramethylpiperidine N-oxide, and 4.64g of calcium acetylacetonate catalyst were added in one step.

[0122] The acetone glycerol content of the raw material was 96.42% by gas chromatography analysis. Figure 1 As shown;

[0123] Start the agitator to stir the materials in the reactor evenly. Use an electric heating oil bath to heat the esterification reactor to a temperature of 106.6℃ to start the reaction. After 5 hours, stop heating. By controlling the reflux ratio of the reflux device at the top of the esterification reactor to (8-12):2, the temperature inside the esterification reactor is 131℃, and the temperature at the top of the distillation column is 93℃. The esterification reaction is completed. During the esterification process, a mixture of azeotropic methyl methacrylate and methanol is separated from the top of the distillation column.

[0124] Step 2: Recover methyl methacrylate and acetone glycerol by vacuum distillation

[0125] Cool down to 54℃, turn on the vacuum system to control the vacuum level at 10.5kPa, and maintain the top temperature of the distillation column at 50-72℃ to recover methyl methacrylate and acetone glycerol.

[0126] Step 3: Collect acetone glyceryl acrylate by vacuum distillation

[0127] The esterification liquid after the recovery of methyl methacrylate and glyceryl acetone was heated further, and the vacuum degree was controlled at 1.6 kPa. The distillation column top temperature was 121-122℃. 218.2 g of glyceryl acetone methacrylate (theoretical 242.43 g) was obtained, with a yield of 90%. The purity was 97.09% by gas chromatography analysis. The acid value was 0.001 mg / g KOH, the platinum-cobalt color was 30, and the moisture content was 0.08%.

[0128] The parallel tests of Example 6 and Comparative Examples 1-5 show that the present invention has the characteristics of high product yield, good product retention, good acid value and platinum-cobalt color, and short esterification reaction time, which shortens the reaction time.

[0129] The above are merely specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing acetone glyceryl methacrylate via transesterification, characterized in that: Detailed steps as follows: The raw material methyl methacrylate and glyceryl acetone, the polymerization inhibitor tetramethylpiperidine nitroxide radical triphosphite, and the catalyst calcium acetylacetonate are added together to an esterification reactor equipped with a stirrer, a distillation column, a top condenser, and a reflux ratio controller. The molar ratio of methyl methacrylate to glyceryl acetone is (2.6-3.1):

1. The amount of polymerization inhibitor added is 0.303%-0.454% of the mass of glyceryl acetone, and the amount of catalyst added is 2.5%-3.5% of the mass of glyceryl acetone. The stirring is started, and the esterification reactor is electrically heated to a temperature of 103℃-107℃ for 3-6 hours. Afterwards, heating is stopped, and the reflux ratio of the reflux device at the top of the esterification reactor is controlled at (8-12):2 to keep the temperature inside the esterification reactor at 121-131.5℃ and the temperature at the top of the distillation column at 92-96℃, thus completing the esterification process. The esterification reactor is then cooled to 43℃-54℃ using circulating water, and the vacuum degree is controlled at 10kPa-13kPa, with the temperature at the top of the distillation column at 40-80℃. Unreacted methyl methacrylate and glyceryl acetone in the feedstock are recovered by vacuum distillation. The vacuum degree is then increased to 1kPa-3kPa, with the temperature at the top of the distillation column at 120℃-123℃. Vacuum distillation continues to collect glyceryl methacrylate.

2. The method for producing acetone glyceryl methacrylate by transesterification according to claim 1, characterized in that: The obtained acetone glyceryl methacrylate product had a purity of 97% as determined by gas chromatography.

3. The method for producing acetone glyceryl methacrylate by transesterification according to claim 1, characterized in that: The mass content of the acetone glycerol is ≥96.4%.

4. The method for producing acetone glyceryl methacrylate by transesterification according to claim 1, characterized in that: During the esterification process, an azeotropic mixture of methyl methacrylate and methanol is separated from the top of the distillation column.

Images