Production of Dimethyl Carbonate Via Reactive Distillation Process

Dimethyl Carbonate (DMC) is an environmentally benign and biodegradable product. Because of its high oxygen content, DMC is an idea additive for gasoline to replace methyl tert-butyl ether (MTBE). DMC has many applications in the synthesis of polycarbonates, production of methyl isocyanate and as a replacement of halogenated solvents.  It is extensively used as a methylating and carbonylating agent. Dimethyl Carbonate has recently becomes an important solvent in the lithium ion battery solutions and other electrochemical and coating sectors.

The early commercial production of DMC via phosgenation of methanol has many draw backs especially the toxicity of phosgene and is being phased out and replaced by other methods. Among these new routes of producing DMC are the oxidative carbonylation of methanol involving CO, transesterification using propylene carbonate or ethylene carbonate to co-produce DMC and propylene glycol or ethylene glycol, and methanolysis of urea.  The merits of each of the new routes of producing DMC will be presented especially the systematic choice of entrainers in the extractive distillation step to separate the DMC-Methanol azeotrope common to all the three routes.