Propylene Glycol by Oxide Hydration

Abstract

Propylene glycol plants are conventionally linked with partially captive propylene oxide. The hydrolysis takes place in two serially connected stirred reactors, operated under pressure. The molar ratio of water to propylene oxide in the feed to the first reactor is 15 to 1. Following the glycol formation, unreacted propylene oxide and bulk water are removed from the reaction mixture. The last traces of water are stripped under vacuum by the glycol drying column. The propylene glycol product is vacuum distilled overhead and then pumped to offsite storage tanks.