Patent ID: 7893305

Claim:
A process for separating one or more diols from a feed mixture comprising one or more diols and one or more polyols, comprising: a) introducing the feed mixture into a wiped-film evaporator; b) distilling the feed mixture in the wiped-film evaporator at a pressure of about 500 to about 2000 Pa and a temperature of about 70 to about 120° C., whereby a first overhead distillate product comprising a first portion of said one or more diols is obtained, and whereby a first bottom product comprising a second portion of said one or more diols is formed in the wiped-film evaporator; c) introducing the first bottom product into a molecular evaporator; and d) distilling the first bottom product in the molecular evaporator at a pressure of about 10 to about 500 Pa and a temperature of about 70 to about 130° C., whereby a second overhead distillate product comprising at least some of the second portion of said one or more diols is obtained, and whereby a second bottom product is formed in the molecular evaporator.