Background and overview of several preparation methods of glycidyl methacrylate
Glycidyl methacrylate (GMA) is a basic organic synthetic raw material and is widely used in electronic materials, functional polymer materials and medical materials, including electronic adhesives, various coatings, ion exchange resins and dental materials, etc. .
Several preparation methods of glycidyl methacrylate
Report on several preparation methods of glycidyl methacrylate 1.
A method for preparing glycidyl methacrylate using 4-dimethylaminopyridine as a catalyst, comprising the following steps:
① Add 30.21g methyl methacrylate, 3.3g glycidol obtained by the ring-closing reaction of 3-chloro-1,2-propanediol methyltetrahydrofuran, 32mg p-hydroxyanisole and 30mg 4-dimethylaminopyridine in sequence into a three-necked flask with a water separator and a thermometer. The reaction temperature is 80°C and the reaction time is 1 hour. During the reaction, nitrogen gas is continuously blown in to remove the methanol produced by the reaction to obtain crude glycidyl methacrylate I;
② The water bath temperature is 50°C, the vacuum degree is 0.08MPa, and the excess methyl methacrylate in the crude glycidyl methacrylate I is distilled under reduced pressure to obtain the crude glycidyl methacrylate II;
③Use column chromatography to purify crude glycidyl methacrylate II, normal phase chromatography conditions are 200-300 mesh silica gel, mass ratio of crude glycidyl methacrylate II to silica gel is 1:10, n-hexane/ether =4/1 (volume ratio), the elution volume is 10 column volumes, collect the fraction containing glycidyl methacrylate, and evaporate to dryness to obtain 7.15g glycidyl methacrylate, with a yield of 85%.
Report 2 on several preparation methods of glycidyl methacrylate,
Reaction stage: Put 54kg sodium methacrylate powder, 139kg epichlorohydrin, 0.35kg triethylbenzyl ammonium chloride, and 0.6kg phenothiazine into the 250L reaction kettle. Stir and raise the temperature to carry out the reaction. Control the temperature of the reactor to 90-95°C. Keep the reaction for 3 hours and then cool down.
Separation stage: The crude reaction liquid is cooled to 40°C and pumped into the horizontal spiral sedimentation centrifuge. The speed is set to 2500rpm. The filtrate is continuously pumped into the continuous distillation equipment through the pump, and the first theoretical plate of the distillation tower is The number is 8, the control temperature is 70°C, the tower top pressure is 4kPa (A), the light component epichlorohydrin is evaporated from the top of the tower for reuse, and the bottom liquid continuously enters the second distillation tower and the theoretical tower through a pump. The number of plates is 15, the control temperature is 90°C, and the tower top pressure is 3kPa (A). Use vacuum distillation to remove the glycidyl alcohol by-product. The bottom liquid continuously enters the third distillation tower through a pump. The theoretical plate number was 15, the temperature was controlled at 110°C, and the tower top pressure was 2.5kPa(A). 52kg of colorless and transparent glycidyl methacrylate product was obtained with a purity of 99.2% and a yield of 72.6%.
Report 3 on several preparation methods of glycidyl methacrylate.
First weigh 86g (1mol) of methacrylic acid into a three-necked flask with stirring, add 0.3g of p-hydroxyanisole, 0.5g of benzyltriethylammonium chloride, and 7.2g of epichlorohydrin 9 barium carbonate. (1.05 mol), heated to 50°C and stirred, monitored by GC, the reaction was complete after 10 hours.
Then lower the temperature to 40°C, add 100g (0.8mol) of 32% liquid caustic soda dropwise within 1 hour, and after the dripping is completed, raise it to 50°C and keep it warm for 1 hour. Pour the reaction solution into the separatory funnel, separate the upper oil phase and return it to the three-necked flask. , then add 0.2g of benzyltriethylammonium chloride, raise the temperature to 40°C, add 37.5g (0.3mol) of 32% liquid caustic soda dropwise within 0.5h, after the dripping is completed, raise to 50°C and keep for 1h, add 30g of water and wash once , 98g of crude product can be obtained after washing.
Finally, add 0.1g p-hydroxyanisole and 0.1g nitroxyl piperidinol to the crude product, and reduce the temperature at the kettle temperature of 40-100°C, the tower top temperature of 30-86°C, and the pressure of 0.6-1.6kpa. Pressure distillation. The unreacted epichlorohydrin was collected and recovered, and 78g of the GMA main fraction was collected, with a GC detection content of 99.4%.
References
[1] [Chinese invention, Chinese invention authorization] CN201310090207.8 A method of preparing glycidyl methacrylate
[2] [Chinese invention, Chinese invention authorization] CN201811524835.1 A catalyst and a method for catalytically preparing glycidyl methacrylate
[3] [Invented in China] CN201911387619.1 A synthesis method of glycidyl methacrylate
