Ethylene Glycol via Ethylene Carbonate

There has been recent patent activity with respect to a process whereby ethylene oxide is converted to ethylene glycol by reaction with CO₂ to form ethylene carbonate, which is in turn hydrolyzed to glycol. We first evaluated this carbonation process in PEP Report No. 70; a new process design and estimate are presented herein, and the economics are compared with those of the conventional ethylene oxide hydration route to glycol.

The carbonation process provides a saving in production cost. This is largely because of a much lower steam requirement, owing to there being less excess water to remove from the glycol. The carbonate process produces smaller amounts of di- and triglycol coproducts, but the smaller requirement of ethylene oxide largely counterbalances the loss in credits.