METHOD FOR PRODUCING GLYCOLIDE

摘要

A method for producing a GL comprising: (I) a heating step of heating a mixture either under normal pressure or reduced pressure at a temperature at which a polyglycolic acid (PGA) undergoes depolymerization, the mixture containing the PGA and a polyethylene glycol ether which is represented by the formula: X—O—(—CH2CH2—O—)p—Y (wherein X and Y are each independently an alkyl group or an aryl group having from 2 to 20 carbon atoms, and p is an integer from 1 to 5) and which has a molecular weight of from 150 to 450 and a boiling point of from 130 to 220° C. at a pressure of 3 kPa; (II) a solution-forming step in which the mixture is rendered in a solution state in which a melt phase of the PGA and a liquid phase consisting of the polyethylene glycol ether essentially form a uniform phase; (III) a GL production step in which a glycolide (GL) is produced by a depolymerization reaction of the PGA by continuing to heat the mixture in the solution state; (IV) a distillation step of distilling off the produced GL together with the polyethylene glycol ether (B) from the depolymerization reaction system; and (V) a recovery step of recovering the GL from the distillate.

主权项

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 at a temperature at which a polyglycolic acid (A) undergoes depolymerization, the mixture containing the polyglycolic acid (A) and a polyethylene glycol ether (B) which is represented by the following formula (1):
X—O—(—CH2CH2—O—)p—Y  (1) (wherein X and Y are each independently an alkyl group or an aryl group having from 2 to 20 carbon atoms, and p is an integer from 1 to 5) and which has a molecular weight of from 150 to 450 and a boiling point of from 130 to 220° C. at a pressure of 3 kPa; (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) essentially form a 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; (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.