Patent ID: 9643949
Date: 2017-05-09
CPC Classifications: C07D

Claim:
1. A method for producing a glycolide by depolymerizing a polyglycolic acid, the method comprising: (I) a heating step of heating a mixture either under normal pressure or reduced pressure to depolymerize a polyglycolic acid (A) wherein a range for the temperature at which the polyglycolic acid (A) undergoes depolymerization is from 190° C. to 232° C., the mixture containing the polyglycolic acid (A) and a polyethylene glycol ether (B) which is represented by the following formula (1): (II) a solution-forming step in which the mixture is rendered in a solution state in which a melt phase of the polyglycolic acid (A) and a liquid phase consisting of the polyethylene glycol ether (B) form a substantially uniform phase; (III) a glycolide production step in which a glycolide is produced by a depolymerization reaction of the polyglycolic acid (A) by continuing to heat the mixture in the solution state under reduced pressure of from 3 to 90 kPa; (IV) a distillation step of distilling off the produced glycolide together with the polyethylene glycol ether (B) from the depolymerization reaction system; and (V) a recovery step of recovering the glycolide from the distillate.