Method for synthesizing glycolide
A technology of glycolide and glycolate, applied in chemical instruments and methods, organic chemistry, chemical/physical/physicochemical processes, etc., can solve the problems of high depolymerization temperature, affecting the purity of glycolide, and the molecular weight distribution of oligomers Width and other issues
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Embodiment 1
[0082] Add 500g methyl glycolate and 2g catalyst stannous octoate into a 1000mL reaction flask, and stir in the reaction flask for 30min, the catalyst and the raw materials are mixed evenly, and then enter the reactive distillation tower at 2mL / min through the feed pump, and the reaction is refined. The upper end of the distillation column is kept at 75°C, and the lower end is kept at two sections: the first section is 150°C and the second section is 230°C. During the reaction, the methanol removal amount is monitored in real time, and the reaction residence time is about 15min; Do GPC analysis of molecular weight) through the material pump into the scraper reactor for depolymerization, the scraper reactor chamber temperature is 260 ℃, the vacuum degree is 1.1kPa, and the generated glycolide is collected.
[0083] During the reaction, 168.3 g of methanol was separated, the theoretical methanol removal amount was 177.8 g, and the average degree of polymerization of the oligomer ...
Embodiment 2
[0086] Add 500g glycolic acid and 1.5g catalyst zinc acetate dihydrate into a 1000mL reaction flask, heat the reaction flask to 100°C, and stir in the reaction flask for 30min, the catalyst and the raw materials are mixed evenly, and then enter through the feed pump at 3mL / min. In the reactive distillation column, the upper end of the reactive distillation column is kept at 110°C, and the bottom end is kept at 230°C. During the reaction, the water removal amount is monitored in real time, and the reaction residence time is about 10 minutes; The material pump enters the scraper reactor for depolymerization. The temperature of the scraper reactor chamber is 260°C and the vacuum degree is 0.9kPa, and the generated glycolide is collected.
[0087] During the reaction, 110.2 g of water was separated, the theoretical water removal amount was 118.5 g, and the average degree of polymerization of the oligomer was 14.3. Collect 378g of glycolide, 8.7g of still residue, and 4.6g of mater...
Embodiment 3
[0090] Add 500g methyl glycolate and 2g catalyst stannous octoate into a 1000mL reaction flask, and stir in the reaction flask for 30min, the catalyst and the raw materials are mixed evenly, and then enter the reactive distillation tower at 3mL / min through the feed pump, and the reaction is refined. The upper end of the distillation column is kept at 75°C, and the lower end is kept at two sections: the first section is 150°C and the second section is 220°C. During the reaction, the methanol removal amount is monitored in real time, and the reaction residence time is about 10min; Do GPC analysis of molecular weight) through the material pump into the scraper reactor for depolymerization, the scraper reactor chamber temperature is 255 ℃, the vacuum degree is 1.1kPa, and the generated glycolide is collected.
[0091] During the reaction, 164.3 g of methanol was separated, the theoretical methanol removal amount was 177.8 g, and the average degree of polymerization of the oligomer ...
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