Process for preparing pentane-1,5-diol

摘要

A process is described for the continuous recovery of substantially pure pentane-1,5-diol from a crude product stream (1) containing pentane-1,5-diol and delta-valerolactone. The feed stream (1) is continuously supplied to a vaporization zone (2) maintained under temperature and pressure conditions effective for the vaporization of pentane-1,5-diol and conducive to the thermal decomposition of reaction products of delta-valerolactone thereby to form a vaporous stream. The resulting vaporous stream is continuously supplied to an intermediate section of a distillation zone (4). A reflux stream (5) of dimethyl glutarate is fed to an upper section of the distillation zone (4) and an overhead vapor product stream (8) comprising delta-valerolactone and dimethyl glutarate is taken. Also an intermediate stream (11) comprising substantially pure pentane-1,5-diol is taken from the distillation zone (4), while from the bottom section of the distillation zone there is recovered a bottoms product (12).