| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a cyclic ester, which comprises depolymerizing aliphatic polyesters of from a low-molecular weight one to a high-molecular weight one efficiently and economically; and to provide a method for purifying a crude cyclic ester efficiently and economically. <P>SOLUTION: The production method of a cyclic ester comprises a step of heating a mixture containing an aliphatic polyester and a polyalkylene glycol ether represented by formula (1) wherein R<SP POS="POST">1</SP>is a methylene group or a 2-8C straight-chain or branched alkylene group; X<SP POS="POST">1</SP>is a hydrocarbon group; Y is a 2-20C alkyl group or an aryl group; p is an integer of ≥1; and when p is ≥2, R<SP POS="POST">1</SP>may be identical or different, and having a boiling point of 230 to 450°C and a molecular weight of 150 to 450, at ordinary or reduced pressure to a temperature at which the depolymerization of the aliphatic polyester is caused. The purification method of a crude cyclic ester comprises a step of heating a mixture of the crude cyclic ester and the polyalkylene glycol at ordinary or reduced pressure. <P>COPYRIGHT: (C)2012,JPO&INPIT |
