Patent ID: 8618322

Claim:
A process for the preparation of an alkanediol and a dialkyl carbonate comprising: (a) reacting an alkylene carbonate and an alkanol in the presence of a transesterification catalyst to obtain a reaction mixture comprising dialkyl carbonate, unconverted alkanol, alkanediol and unconverted alkylene carbonate; (b) subjecting the reaction mixture to distillation in a first distillation column to obtain a top stream comprising dialkyl carbonate and alkanol and a bottom stream comprising dialkyl carbonate, alkanol, alkanediol and alkylene carbonate; (c) subjecting the bottom stream from the first distillation column to distillation in a second distillation column to obtain a top stream comprising dialkyl carbonate and alkanol and a bottom stream comprising alkanediol and alkylene carbonate; (d) recovering alkanediol from the bottom stream from the second distillation column; and (e) subjecting the top streams from the first and second distillation columns to distillation in a third distillation column to obtain a top stream comprising alkanol and a bottom stream comprising dialkyl carbonate.