METHOD FOR PRODUCING GLYCOLIDE

摘要

A method for producing glycolide (GL) by heating a glycolic acid oligomer (GAO) to depolymerize the GAO. The method for producing GL comprises: a step 1 of heating a mixture containing a GAO having a terminal COOH concentration of 400 eq/t or less and a polar organic solvent to a GAO depolymerization temperature under ambient pressure or reduced pressure; a step 2 of continuing the heating at the temperature for depolymerizing of the GAO and then codistilling out the produced GL and the solvent from the depolymerization reaction system to the outside the reaction system; and a step 3 of obtaining GL from the codistillation product. In the method for producing GL, the GAO is preferably prepared by a GAO production method which comprises a step of condensing glycolic acid (GA) and a dehydration step of continuing the heating together with a polar organic solvent or a depolymerization reaction solution to allow the GA condensation reaction to continue.;

主权项

1. A method for producing glycolide by heating a glycolic acid oligomer to depolymerize, the method comprising steps below:
I. a step 1 of heating a mixture containing a glycolic acid oligomer having a terminal carboxyl group concentration of 400 eq/t or less and a polar organic solvent to a temperature for depolymerizing the glycolic acid oligomer under ambient pressure or reduced pressure; II. a step 2 of continuing the heating at the temperature for depolymerizing the glycolic acid oligomer and then codistilling out, together with the polar organic solvent, glycolide produced by the depolymerization from a depolymerization reaction system containing the mixture; and III. a step 3 of obtaining glycolide from the codistillation product.