High-purity glycolide preparation method
A glycolide, high-purity technology, applied in the field of preparation of high-purity glycolide, can solve the problems of low lactide yield, high cost, low purity, etc., and achieve the effect of less by-products and short reaction time
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Embodiment 1
[0037] A preparation method of high-purity glycolide, comprising steps as follows:
[0038] Weigh 500g of glycolic acid, pour it into a three-necked flask equipped with a thermometer, a condensation device and a stirrer, heat slowly to boiling, decompress and dehydrate at a pressure of 0.04~0.06MPa, add 4g of zinc oxide (glycolic acid Its mass ratio is 125), keep the dehydration under reduced pressure for 2 hours, and the pressure is 0.06-0.09MPa, so that glycolic acid can be polycondensed into glycolic acid oligomers. The pressure is 1500Pa~0.1MPa, and the crude glycolide is collected by the three-stage cooling collection system. The product is a yellow solid, and the crude product yield is 92%. The crude product is dissolved in methanol, cooled, filtered, recrystallized with methanol three times, and dried in vacuum The finished product is obtained when the weight is constant, the yield is 78%, and the purity of glycolide is 99.92% after inspection.
Embodiment 2
[0040] A preparation method of high-purity glycolide, comprising steps as follows:
[0041] Weigh 500g of glycolic acid, pour it into a three-necked flask equipped with a thermometer, condensing device and stirrer, slowly heat to boiling, decompress and dehydrate at a pressure of 0.04~0.06MPa, add 2g of antimony trioxide ( The ratio of glycolic acid to its mass is 250), keep dehydration under reduced pressure for 6 hours, and the pressure is 0.06-0.09MPa, so that glycolic acid can be polycondensed into glycolic acid oligomers. , the distillation pressure is 1500Pa~0.1MPa, the crude glycolide is collected by a three-stage cooling collection system, the product is a yellow solid, and the yield of the crude product is 94%. Recrystallize three times, vacuum dry to constant weight to get the finished product, the yield is 77%, and the purity of glycolide is 99.95% after inspection.
Embodiment 3
[0043] A preparation method of high-purity glycolide, comprising steps as follows:
[0044] Weigh 500g of glycolic acid, pour it into a three-neck flask equipped with a thermometer, a condensation device and a stirrer, heat slowly to boiling, decompress and dehydrate at a pressure of 0.05~0.06MPa, add 5g of alumina (glycolic acid) when the temperature rises to 150°C Its mass ratio is 100), keep the dehydration under reduced pressure for 7 hours, and the pressure is 0.07-0.09MPa, so that glycolic acid can be polycondensed into glycolic acid oligomers. The pressure is 1500Pa~0.1MPa, and the crude glycolide is collected by the three-stage cooling collection system. The product is a yellow solid, and the crude product yield is 90%. The crude product is dissolved in methanol, cooled, filtered, recrystallized with methanol three times, and dried in vacuum The finished product is obtained when the weight is constant, the yield is 76%, and the purity of glycolide is 99.93%.
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