Method for producing n-decyl methacrylate through ester exchange

Abstract

The invention relates to a method for producing n-decyl methacrylate by ester exchange, which comprises the following steps: adding methyl methacrylate, n-decyl alcohol, a polymerization inhibitor tetramethylpiperidine nitroxide free radical phosphite triester and a composite catalyst into an esterification reactor, electrifying the esterification reactor for heating, heating to 106-109 DEG C, reacting for 5-7 hours, stopping heating, controlling the reflux ratio of a reflux device at the top of the esterification reactor, and reacting for 2-3 hours to obtain n-decyl methacrylate; the temperature in the esterification reactor is made to be 125-137 DEG C, the temperature of the top end of a rectifying column of the esterification reactor is made to be 94-98 DEG C, after the esterification reaction is finished, water cooling is carried out to lower than 40 DEG C, an esterification reaction product is obtained, filtering is carried out, catalyst residues are removed, vacuum rectification is carried out, after methyl methacrylate and n-decyl alcohol are recycled, vacuum rectification is carried out, and n-decyl methacrylate is obtained. The method has the advantages that the process is simple and reasonable, the catalytic effect is good, the composite catalyst containing the organic calcium catalyst is not easy to decompose, the product is good in storage stability, high in purity and small in chromaticity, and the use requirements of users are met.

Description

Technical Field

[0001] The invention relates to a method for producing n-decyl methacrylate through esterification. Background Art

[0002] Decyl methacrylate is a highly active monomer containing unsaturated double bonds. Its double bond structure gives the polymer excellent properties such as weather resistance, chemical resistance and water resistance, making it widely used in optical glue, ink, coating, adhesive and lubricant additives. However, due to the long carbon chain and high boiling point of the molecule, the catalytic efficiency of organotin catalysts is low, the dosage is large, and it is difficult to separate from the system during the production process. The distillation process produces kettle residues, which not only reduces the product yield, but also causes secondary pollution during incineration. The trace moisture contained in the raw materials and the decomposition products of organocalcium catalysts at a specific temperature will also dissolve into the product, causing product discoloration and reduced storage stability, making it difficult to meet user application needs.

[0003] With the development of science and technology and the improvement of environmental protection requirements, products must not only meet the needs of the application field, but also put forward higher requirements for the raw materials used in the entire production process, such as non-toxic and harmless raw materials, easy waste disposal and no secondary pollution. At present, the production of n-decyl methacrylate is mainly synthesized by the alcohol acid method or the ester exchange method, and the catalysts used are all traditional ester exchange catalysts, organotin catalysts, which have high catalytic activity. CN1097742A uses calcium acetylacetonate dibutyltin oxide composite catalyst, CN105294434A uses calcium acetylacetonate organotin composite catalyst, although both methods have high alcohol conversion rate and good yield, but due to the use of calcium acetylacetonate as a catalyst, when the temperature is higher than 110 ° C, there is a trace of water or it will decompose into acetylacetone at a temperature higher than 160 ° C and remain in the product, causing unstable product color during storage, unqualified color, and the used dibutyltin oxide organotin catalyst also has an impact on product color, and the tin content cannot meet the requirements of the application field, and the residual still containing the organotin catalyst needs to be incinerated, which produces secondary pollution and limits its use. Therefore, replacing the organotin catalyst in the transesterification production process does not produce secondary pollution, which has great practical significance for the production of n-decyl methacrylate.

[0004] Journal of Hunan University of Arts and Science Vol.20No.4 Dec.2008 "Synthesis of Higher Alcohol Methacrylate Esters by Ester Exchange Reaction" uses magnetic Mg-Al-HT catalyst to synthesize higher carbon alcohol esters, among which the conversion rate of n-decanol is as high as 82%; at the same time, there are also introductions abroad using hydrotalcite or hydrotalcite-like (LDO / LDH) solid base catalysts, but the yield and purity are not ideal. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for producing n-decyl methacrylate by ester exchange with high purity and low chroma. The process is simple and reasonable, the catalytic effect is good, the composite catalyst containing the organic calcium catalyst is not easy to decompose, the product has good storage stability, and the use requirements of users are met.

[0006] The technical solution of the present invention is: A method for producing n-decyl methacrylate by transesterification, the specific steps of which are as follows: (1) Esterification reaction: methyl methacrylate, n-decanol, tetramethylpiperidinium nitroxide free radical phosphite and a composite catalyst are added to an esterification reactor, wherein the composite catalyst is a mixture of calcium acetylacetonate and calcium oxide, wherein the molar ratio of methyl methacrylate to n-decanol is (2.8-3.3):1, the amount of the polymerization inhibitor added is 0.1%-0.3% of the mass of n-decanol, and the amount of the composite catalyst added is 0.22%-0.35% of the mass of n-decanol; the esterification reactor is powered on and heated to 106°C-109°C for 5h-7h, then the heating is stopped, and the reflux ratio of the reflux device at the top of the esterification reactor is controlled to be (10-20):2, so that the temperature in the esterification reactor is 125-137°C, and the temperature at the top of the distillation column of the esterification reactor is 94-98°C. The esterification reaction is completed, and the esterification reactor is cooled by water to below 40°C to obtain an esterification reaction product; (2) Filtration and vacuum distillation: The esterification reaction product is filtered to remove the catalyst residue and the esterification reaction product filtrate is collected; the filtered esterification reaction product filtrate is subjected to vacuum distillation to recover methyl methacrylate and n-decanol in the esterification reaction product filtrate and then vacuum distillation is performed to obtain n-decyl methacrylate.

[0007] Furthermore, the mass ratio of calcium acetylacetonate to calcium oxide in the composite catalyst is (6-10):1.

[0008] Furthermore, the purity of the n-decyl methacrylate is ≥99%.

[0009] Furthermore, the obtained n-decyl methacrylate has a platinum-cobalt color of ≤10, an acid value of ≤0.002 mg / g KOH, and a moisture content of ≤0.05%.

[0010] Furthermore, when the methyl methacrylate and n-decanol in the filtrate of the esterification reaction product are recovered by vacuum distillation, the vacuum degree is 10KPa-13KPa and the distillation temperature is 48-160°C.

[0011] Furthermore, when obtaining n-decyl methacrylate by vacuum distillation, the vacuum degree is controlled at 1 KPa to 3 KPa, and the distillation temperature is 160° C. to 165° C.

[0012] Furthermore, the mass content of the n-decanol is ≥99.17%.

[0013] The beneficial effects of the present invention are: 1. By adopting methyl methacrylate, n-decyl alcohol and a composite catalyst of calcium acetylacetonate and calcium oxide, an efficient, green, safe and environmentally friendly production process route is achieved; this process not only reduces the amount of catalyst used, but also avoids the use of organic tin catalysts, thereby reducing pollution to the environment.

[0014] 2. The purity of the obtained n-decyl methacrylate product is as high as over 99%, and key indicators such as platinum cobalt color, acid value, and moisture content all meet or exceed industry standards, meeting the needs of various fields for this product.

[0015] 3. In the esterification process, the catalyst is first separated by filtration, and then the excess methyl ester and the remaining n-decanol are recovered by vacuum distillation, thereby achieving efficient utilization of raw materials, while increasing the yield of the product and reducing the chromaticity.

[0016] 4. The composite catalyst calcium acetylacetonate and calcium oxide not only does not corrode equipment, but also when the raw materials contain trace amounts of water, calcium oxide can absorb water to generate calcium hydroxide, thereby avoiding the hydrolysis of calcium acetylacetonate, thereby ensuring the color of the product. The product does not change color after being stored for six months and has good storage stability. At the same time, the acetylacetone generated by the decomposition of the catalyst calcium acetylacetonate can react with calcium hydroxide to regenerate the calcium acetylacetonate catalyst, further improving the catalytic efficiency.

[0017] 5. The inhibitor used has high efficiency and process control is adopted in the whole reaction to ensure the smooth progress of esterification reaction and distillation process and easy operation.

[0018] 6. There is little residue in the distillation kettle, the product yield is high, and the calcium oxide generated after the kettle residue is incinerated can be recycled without causing secondary pollution.

[0019] 7. The present invention not only meets the needs of n-decyl methacrylate in various fields, but also realizes industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 1); Figure 2 is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 2); Figure 3 is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 3); Figure 4 is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 4); Figure 5is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 1); Figure 6 is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 2); Figure 7 It is a gas chromatogram of n-decyl methacrylate of the present invention (corresponding to Example 3). DETAILED DESCRIPTION

[0021] Example 1 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 416 grams of methyl methacrylate, 200 grams of n-decyl alcohol, 0.20 grams of tetramethylpiperidinium nitroxide free radical phosphite triester as a polymerization inhibitor, 0.4 grams of calcium acetylacetonate as a catalyst, and 0.04 grams of calcium oxide were added at once. The mass content of the raw material n-decyl alcohol was 99.17% by gas chromatography analysis. The stirrer was turned on to stir the materials in the four-necked flask evenly. The four-necked flask was heated to 109°C with an electric heating oil bath to start the reaction. The reaction lasted for 10 minutes. After 7 hours, the heating was stopped, and the reflux ratio of the reflux ratio controller at the top of the four-necked flask was controlled to be (10-20):2, so that the temperature in the four-necked flask was 137°C, and the temperature at the top of the distillation column of the four-necked flask was 98°C, and the esterification reaction was completed; the circulating water coil was opened to cool the esterification reaction liquid in the four-necked flask to 40°C through the circulating water, and the esterification filtrate was obtained by vacuum suction filtration through a suction flask with a Buchner funnel with filter paper, and the esterification filtrate was 401.5 grams. The n-decanol content of the esterification filtrate was analyzed to be 0.01%, and the alcohol conversion rate was (200-401.5×0.01%)÷200×100%=99.98%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, the vacuum system is turned on to control the vacuum degree to 10KPa, the temperature in the kettle of the distillation device is 48-160°C, and methyl methacrylate and n-decanol are recovered; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled to be 1 KPa. The top temperature of the distillation device was 160-162°C. 280.5 g (theoretical 286 g) of n-decyl methacrylate was obtained in the fraction, and the yield was 98%. The gas chromatogram of n-decyl methacrylate is shown in Figure 1 As shown, the peak time is 13.352 minutes, the purity is 99.22% after gas chromatography analysis, the platinum cobalt color is 5, the acid value is 0.002mg / g KOH, and the water content is 0.019%. The platinum cobalt color of the product after 6 months of storage is 5.

[0022] Example 2 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 354 g of methyl methacrylate, 200 g of n-decyl alcohol, 0.6 g of tetramethylpiperidinium nitroxide free radical phosphite triester as an inhibitor, 0.6 g of calcium acetylacetonate as a catalyst, and 0.1 g of calcium oxide were added at once. The mass content of the raw material n-decyl alcohol was 99.17% according to gas chromatography analysis. The stirrer was turned on to stir the materials in the four-necked flask evenly. The four-necked flask was heated to 106°C with an electric heating oil bath to start the reaction. The reaction lasted for 2 hours. 5 hours, stop heating, control the reflux ratio of the reflux ratio controller at the top of the four-necked flask to (10-20):2, make the temperature in the four-necked flask to 125°C, and the temperature at the top of the distillation column of the four-necked flask to 94°C, and the esterification reaction is finished; open the circulating water coil to cool the esterification reaction liquid in the four-necked flask to 40°C through circulating water, use a Buchner funnel with filter paper to vacuum filter through a suction flask to obtain 416.7 grams of esterification filtrate, and analyze the esterification filtrate to find that the n-decanol content is 0.01%, and the alcohol conversion rate is (200-416.7×0.01%)÷200×100%=99.97%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 13 KPa. The temperature in the kettle of the distillation device is set at 68-160° C. to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled to be 3 KPa. The top temperature of the distillation device was 163-165°C. 280.5 g (theoretical 286 g) of n-decyl methacrylate was obtained in the fraction, and the yield was 98.07%. The gas chromatogram of n-decyl methacrylate is shown in Figure 2 As shown, the peak time is 13.308 minutes, the purity is 99.34% after gas chromatography analysis, the platinum cobalt color is 10, the acid value is 0.001 mg / g KOH, and the water content is 0.016%. The platinum cobalt color of the product after 6 months of storage is 10.

[0023] Example 3 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 380 grams of methyl methacrylate, 200 grams of n-decyl alcohol, 0.4 grams of tetramethylpiperidinium nitroxide free radical phosphite triester as a polymerization inhibitor, 0.5 grams of calcium acetylacetonate as a catalyst, and 0.06 grams of calcium oxide were added at once. The mass content of the raw material n-decyl alcohol was 99.17% by gas chromatography analysis. The stirrer was started to stir the materials in the four-necked flask evenly. The four-necked flask was heated to 108°C with an electric heating oil bath to start the reaction. The reaction lasted for 10 minutes. After 6 hours, the heating was stopped, and the reflux ratio of the reflux ratio controller at the top of the four-necked flask was controlled to be (10-20):2, so that the temperature in the four-necked flask was 130°C, and the temperature at the top of the distillation column of the four-necked flask was 96°C, and the esterification reaction was completed; the circulating water coil was opened to cool the esterification reaction liquid in the four-necked flask to 40°C through the circulating water, and the esterification filtrate was obtained by vacuum suction filtration through a suction flask with a Buchner funnel with filter paper, and the esterification filtrate was 406.8 grams. The n-decanol content of the esterification filtrate was analyzed to be 0.01%, and the alcohol conversion rate was (200-406.8×0.01%)÷200×100%=99.97%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 11 KPa. The temperature in the kettle of the distillation device is set at 62-150° C. to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled to be 3 KPa. The top temperature of the distillation device was 163-165°C. 281 g of n-decyl methacrylate was obtained in the fraction (theoretical 286 g), and the yield was 98.2%. The gas chromatogram of n-decyl methacrylate is shown in Figure 3 As shown, the peak time is 13.317 minutes. The purity is 99.17% after gas chromatography analysis, the platinum-cobalt color is 5, the acid value is 0.001 mg / g KOH, and the water content is 0.02%. The platinum-cobalt color of the product is 5 after 6 months of storage.

[0024] Example 4 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 425 grams of recovered methyl methacrylate, 210 grams of n-decyl alcohol, 0.315 grams of tetramethylpiperidinium nitroxide free radical phosphite triester as a polymerization inhibitor, 0.42 grams of calcium acetylacetonate as a catalyst, and 0.06 grams of calcium oxide were added at once; the mass content of the raw material n-decyl alcohol was 99.17% by gas chromatography analysis; the stirrer was turned on to stir the materials in the four-necked flask evenly, and the four-necked flask was heated to 107°C with an electric heating oil bath to start the reaction, and the reaction After 6.5 hours, the heating was stopped, and the reflux ratio of the reflux ratio controller at the top of the four-necked flask was controlled to be (10-20):2, so that the temperature in the four-necked flask was 132°C, and the temperature at the top of the distillation column of the four-necked flask was 94°C, and the esterification reaction was completed; the circulating water coil was opened to cool the esterification reaction liquid in the four-necked flask to 40°C through the circulating water, and a Buchner funnel with filter paper was used to vacuum filter through a suction filter bottle to obtain 421.6 grams of esterification filtrate. The n-decanol content of the esterification filtrate was analyzed to be 0.01%, and the alcohol conversion rate was (210-421.6×0.01%)÷210×100%=99.98%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 12 KPa. The temperature in the kettle of the distillation device is 64-156°C to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled to be 2.5 KPa. The top temperature of the distillation device was 164-165°C. 295.5 g of n-decyl methacrylate was obtained in the fraction (theoretical 300.31 g), and the yield was 98.39%. The gas chromatogram of n-decyl methacrylate is shown in Figure 4 As shown, the peak time is 13.318 minutes, the purity is 99.17% after gas chromatography analysis, the platinum-cobalt color is 5, the acid value is 0.001 mg / g KOH, and the water content is 0.018%. The platinum-cobalt color of the product after 6 months of storage is 5.

[0025] Example 5 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 156 g of recovered methyl methacrylate and 236 g of commercially available methyl methacrylate, 200 g of n-decyl alcohol, 0.5 g of tetramethylpiperidinium nitroxide free radical phosphite triester as an inhibitor, 0.54 g of calcium acetylacetonate as a catalyst, and 0.06 g of calcium oxide were added at once. The mass content of the raw material n-decyl alcohol was 99.17% by gas chromatography analysis. The stirrer was turned on to stir the materials in the four-necked flask evenly, and the four-necked flask was heated to 106.5 with an electric heating oil bath. The reaction was started at 40 °C. After 6 hours of reaction, the heating was stopped. The reflux ratio of the reflux ratio controller at the top of the four-necked flask was controlled to be (10-20):2, so that the temperature in the four-necked flask was 129 °C, and the temperature at the top of the distillation column of the four-necked flask was 96 °C, and the esterification reaction was completed. The circulating water coil was opened to cool the esterification reaction liquid in the four-necked flask to 40 °C through the circulating water. The esterification filtrate was obtained by vacuum suction filtration through a suction flask with a Buchner funnel with a filter cloth. The n-decanol content of the esterification filtrate was 0.02% by analysis, and the alcohol conversion rate was (200-408.8×0.02%)÷200×100%=99.95%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 11 KPa. The temperature in the kettle of the distillation device is 54-158°C to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The esterification filtrate after the recovery of methyl methacrylate and n-decyl alcohol was heated up again, the vacuum degree was controlled at 2KPa, the top temperature of the distillation device was 163-165°C, and 281.7 g (theoretical 286 g) of n-decyl methacrylate was obtained in the fraction, the yield was 98.49%, the purity was 99.3% after gas chromatography analysis, the platinum-cobalt color was 5, the acid value was 0.001 mg / g KOH, and the water content was 0.02%. The product was stored for 6 months and the platinum-cobalt color was re-measured to be 5.

[0026] Comparative Example 1 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 354 g of methyl methacrylate, 200 g of n-decyl alcohol, 0.6 g of tetramethylpiperidinium nitroxide free radical phosphite triester as an inhibitor, and 0.7 g of dibutyltin dilaurate as a catalyst were added at once. The mass content of the raw material n-decyl alcohol was 99.17% according to gas chromatography analysis. The stirrer was turned on to stir the materials in the four-necked flask evenly. The four-necked flask was heated to 109°C with an electric heating oil bath to start the reaction. The reaction lasted for 10 After 1 hour, the heating was stopped, and the reflux ratio of the reflux ratio controller at the top of the four-necked flask was controlled to be (10-20):2, so that the temperature in the four-necked flask was 125°C, and the temperature at the top of the distillation column of the four-necked flask was 98°C, and the esterification reaction was completed; the circulating water coil was opened to cool the esterification reaction liquid in the four-necked flask to 40°C through the circulating water, and a Buchner funnel with filter paper was used to vacuum filter through a suction filter bottle to obtain 393.7 grams of esterification filtrate. The n-decanol content of the esterification filtrate was 5.2% by analysis, and the alcohol conversion rate was (200-393.7×5.2%)÷200×100%=89.77%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 13 KPa. The temperature in the kettle of the distillation device is 68-160° C. to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled to be 3 KPa. The top temperature of the distillation device was 163-165°C. 236.2 g of n-decyl methacrylate was obtained in the distillate (179.5 g of alcohol was reacted, 256.7 g was theoretically obtained), and the yield was 92.01%. The gas chromatogram of n-decyl methacrylate is shown in Figure 5 As shown, the peak time is 13.29 minutes, the purity is 99.15% after gas chromatography analysis, the platinum cobalt chromaticity is 100, the product chromaticity is high, the acid value is 0.005 mg / g KOH, and the water content is 0.06%.

[0027] Comparative Example 2 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 354 grams of methyl methacrylate, 200 grams of n-decyl alcohol, 0.6 grams of tetramethylpiperidinium nitroxide free radical phosphite triester as a polymerization inhibitor, and 0.7 grams of calcium acetylacetonate as a catalyst were added at once. The mass content of n-decyl alcohol was 99.17% according to gas chromatography analysis. The stirrer was turned on to stir the materials in the four-necked flask evenly. The four-necked flask was heated with an electric heating oil bath to 108°C to start the reaction. The reaction lasted for 8 hours. Stop heating, and control the reflux ratio of the reflux ratio controller at the top of the four-necked flask to (10-20):2, so that the temperature in the four-necked flask is 127°C, and the temperature at the top of the distillation column of the four-necked flask is 94°C, and the esterification reaction is finished; open the circulating water coil to cool the esterification reaction liquid in the four-necked flask to 40°C through circulating water, and use a Buchner funnel with filter paper to vacuum filter through a suction filter bottle to obtain 405.8 grams of esterification filtrate. The esterification filtrate is analyzed to have a n-decanol content of 0.8%, and the alcohol conversion rate is (200-405.8×0.8%)÷200×100%=98.38%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 13 KPa. The temperature in the kettle of the distillation device is 68-160° C. to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled at 3 KPa. The top temperature of the distillation device was 163-165 ° C. 267.5 g of n-decyl methacrylate was obtained in the fraction (theoretical 281.3 g), and the yield was 95.1%. The gas chromatogram of n-decyl methacrylate is as follows: Figure 6 As shown, the peak time is 13.292 minutes, the purity is 99.17% after gas chromatography analysis, the platinum cobalt color is 30, the acid value is 0.002 mg / g KOH, and the water content is 0.08%. After being placed for 7 days, the product turns yellow and the platinum cobalt color is greater than 100.

[0028] Comparative Example 3 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 354 g of methyl methacrylate, 200 g of n-decyl alcohol, 0.6 g of tetramethylpiperidinium nitroxide free radical phosphite triester as an inhibitor, 0.64 g of calcium acetylacetonate as a catalyst, and 0.06 g of dibutyltin oxide were added at once. The mass content of the raw material n-decyl alcohol was 99.17% according to gas chromatography analysis; the stirrer was turned on to stir the materials in the four-necked flask evenly, and the four-necked flask was heated to 109°C with an electric heating oil bath to start the reaction. After 9 hours of reaction, the heating was stopped, and the reflux ratio of the reflux ratio controller at the top of the four-necked flask was controlled to be (10-20):2, so that the temperature in the four-necked flask was 126°C, and the temperature at the top of the distillation column of the four-necked flask was 96°C, and the esterification reaction was completed; the circulating water coil was opened to cool the esterification reaction liquid in the four-necked flask to 40°C through the circulating water, and the esterification filtrate was obtained by vacuum suction filtration through a suction flask with a Buchner funnel with filter paper, and the esterification filtrate was 408 grams. The n-decanol content of the esterification filtrate was 1.05% by analysis, and the alcohol conversion rate was (200-408×1.05%)÷200×100%=97.86%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 13 KPa. The temperature in the kettle of the distillation device is 68-160° C. to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The temperature of the esterified filtrate after the methyl methacrylate and n-decyl alcohol were recovered was further raised, and the vacuum degree was controlled at 3 KPa. The top temperature of the distillation device was 163-165 ° C. 260.3 g of n-decyl methacrylate was obtained in the fraction (theoretical 279.8 g), and the yield was 93.03%. The gas chromatogram of n-decyl methacrylate is shown in Figure 7 As shown, the peak time is 13.305 minutes, the purity is 99.15% after gas chromatography analysis, the platinum cobalt color is 60, the acid value is 0.005 mg / g KOH, and the water content is 0.07%. After 7 days of storage, the material turns yellow and the platinum cobalt color is greater than 100.

[0029] Comparative Example 4 Step 1: Esterification In a 1L four-necked flask equipped with an electric heating oil bath with a circulating water coil, and equipped with a stirrer, a thermocouple, a distillation column, a reflux ratio controller, a condenser, and a receiving bottle, 354 g of methyl methacrylate, 200 g of n-decyl alcohol, 0.6 g of tetramethylpiperidinium nitroxide free radical phosphite triester as an inhibitor, and 0.7 g of calcium acetylacetonate as a catalyst were added at once. The mass content of n-decyl alcohol was 99.17% according to gas chromatography analysis. The stirrer was turned on to stir the materials in the four-necked flask evenly. The four-necked flask was heated with an electric heating oil bath to 108°C to start the reaction. After 8.5 hours, the heating should be stopped, and the reflux ratio of the reflux ratio controller at the top of the four-necked flask should be controlled to (10-20):2, so that the temperature in the four-necked flask is 128°C, and the temperature at the top of the distillation column of the four-necked flask is 96°C, and the esterification reaction is finished; the circulating water coil is opened to cool the esterification reaction liquid in the four-necked flask to 40°C through the circulating water, and 403.2 grams of esterification filtrate is obtained without filtering. The n-decanol content of the esterification filtrate is analyzed to be 0.56%, and the alcohol conversion rate is (200-403.2×0.56%)÷200×100%=98.87%; Step 2: Recovery of methyl methacrylate and n-decanol by vacuum distillation The esterification filtrate is transferred to a distillation device, and the vacuum system is turned on to control the vacuum degree to 13 KPa. The temperature in the kettle of the distillation device is 68-160° C. to recover methyl methacrylate and n-decanol; Step 3: Collect n-decyl methacrylate by vacuum distillation The esterification filtrate after the recovery of methyl methacrylate and n-decyl alcohol was heated up again, the vacuum degree was controlled at 3KPa, the top temperature of the distillation device was 163-165°C, and 225.8g of n-decyl methacrylate was obtained in the fraction (theoretical 282.7g), the yield was 79.87%, the purity was 99.15% after gas chromatography analysis, the platinum cobalt color was 100, the acid value was 0.002mg / g KOH, and the water content was 0.07%. After 7 days of storage, the product color was yellow, which was beyond the range and could not be measured.

[0030] Compared with Comparative Example 1, Comparative Example 4 did not filter the catalyst and directly carried out vacuum distillation, and the product yield was lower; since the catalyst was in the reaction liquid, after vacuum distillation, the reaction liquid was partially polymerized into oligomers during the distillation process in the presence of the catalyst and could not be evaporated, resulting in a decrease in yield. At the same time, the catalyst decomposed into acetylacetone, which was oxidized and discolored, causing the color of the material to darken. Further oxidation during the storage process further deepened the color of the material, and the chromaticity stability of the product was poor.

[0031] The raw materials of the method are easily available, and the whole process is controlled by cooling, filtering and removing the catalyst after esterification, and then vacuum distillation. The entire esterification reaction and distillation separation process operation realizes an efficient, safe, stable and environmentally friendly production process. The use of a composite catalyst calcium acetylacetonate and calcium oxide compound does not produce harmful substances and does not corrode the equipment. It is safe, environmentally friendly and efficient.

[0032] The process has great advantages. The final product has a purity of ≥99.17%, a platinum-cobalt color of ≤10, an acid value of ≤0.002mg / g KOH, and a moisture content of ≤0.02%. The conversion rate is as high as 99.95%, and the yield is as high as 98%. It can fully realize industrial production, and the products meet the needs of various fields.

Claims

1. A method for producing n-decyl methacrylate by transesterification, characterized in that: Specific steps as follows: (1) Esterification reaction: methyl methacrylate, n-decanol, tetramethylpiperidinium nitroxide free radical phosphite and a composite catalyst are added to an esterification reactor, wherein the composite catalyst is a mixture of calcium acetylacetonate and calcium oxide, wherein the molar ratio of methyl methacrylate to n-decanol is (2.8-3.3):1, the amount of the polymerization inhibitor added is 0.1%-0.3% of the mass of n-decanol, and the amount of the composite catalyst added is 0.22%-0.35% of the mass of n-decanol; the esterification reactor is powered on and heated to 106°C-109°C for 5h-7h, then the heating is stopped, and the reflux ratio of the reflux device at the top of the esterification reactor is controlled to be (10-20):2, so that the temperature in the esterification reactor is 125-137°C, and the temperature at the top of the distillation device of the esterification reactor is 94-98°C. The esterification reaction is completed, and the esterification reactor is cooled by water to below 40°C to obtain an esterification reaction product; (2) Filtration and vacuum distillation: The esterification reaction product is filtered to remove the catalyst residue and the esterification reaction product filtrate is collected; the filtered esterification reaction product filtrate is subjected to vacuum distillation to recover methyl methacrylate and n-decanol in the esterification reaction product filtrate, and then vacuum distillation is performed to obtain n-decyl methacrylate.

2. The method for producing n-decyl methacrylate by transesterification according to claim 1, characterized in that: The mass ratio of calcium acetylacetonate to calcium oxide in the composite catalyst is (6-10):

1.

3. The method for producing n-decyl methacrylate by transesterification according to claim 1, characterized in that: The purity of the n-decyl methacrylate is ≥99%.

4. The method for producing n-decyl methacrylate by transesterification according to claim 1, characterized in that: The obtained n-decyl methacrylate has a platinum-cobalt color of ≤10, an acid value of ≤0.002 mg / g KOH, and a moisture content of ≤0.05%.

5. The method for producing n-decyl methacrylate by transesterification according to claim 1, characterized in that: When methyl methacrylate and n-decanol are recovered from the filtrate of the esterification reaction product by vacuum distillation, the vacuum degree is 10KPa-13KPa and the distillation temperature is 48-160°C.

6. The method for producing n-decyl methacrylate by transesterification according to claim 1, characterized in that: When obtaining n-decyl methacrylate by vacuum distillation, the vacuum degree is controlled at 1 KPa to 3 KPa, and the distillation temperature is 160°C to 165°C.

7. The method for producing n-decyl methacrylate by transesterification according to claim 1, characterized in that: The mass content of the n-decanol is ≥99.17%.

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