The present invention provides a process for production of a cyclic ester by depolymerization of an aliphatic polyester. In the process, a mixture containing the aliphatic polyester and a specific polyalkylene glycol ether, which has a boiling point of 230-450° C. and a molecular weight of 150-450, is heated under normal or reduced pressure to a temperature at which depolymerization of the aliphatic polyester takes place. Then, a substantially homogeneous solution phase, consisting of the melt phase of the aliphatic polyester and the liquid phase of the polyalkylene glycol ether, is formed. Heating of the solution phase is continued to form the cyclic ester by depolymerization and distil out the cyclic ester together with the polyalkylene glycol ether, and then the cyclic ester is recovered from the distillate. The present invention also provides a process for purification of a crude cyclic ester by use of the specific polyalkylene glycol ether described above.
本发明提供了一种通过脂肪族聚酯的降解来生产环酯的方法。在该过程中,将含有脂肪族聚酯和具有沸点在230-450°C和分子量在150-450之间的特定聚烷基
乙二醇醚的混合物,在常压或减压下加热至脂肪族聚酯发生降解的温度。然后,形成由脂肪族聚酯的熔融相和聚烷基
乙二醇醚的液相组成的基本均相溶液相。继续加热溶液相以通过降解形成环酯并与聚烷基
乙二醇醚一起蒸馏出环酯,然后从馏出物中回收环酯。本发明还提供了一种利用上述特定聚烷基
乙二醇醚对粗环酯进行纯化的方法。