Method of reducing the oligomeric cyclic ether content of polybutylene oxide-polyalkylene oxide glycols

摘要

1. A process for reducing the content of oligomeric cyclic ethers in a polyoxybutylene polyoxyalkylene glycol, in which a copolymer obtained by copolymerization of tetrahydrofuran with a 1,2-alkylene oxide in the presence of a compound containing reactive hydrogen, under the catalytic action of a bleaching earth, is subjected to vacuum distillation at elevated temperature in order to remove the oligomeric cyclic ethers, characterized in that, prior to the vacuum distillation, the copolymer is treated with oxygen at from 20 to 110 degrees C by passing in oxygen or an oxygen-containing gas, from 1 to 8 parts by weight of oxygen being used per 1 000 parts by weight of copolymer, and the vacuum distillation is then carried out at above 200 degrees C.