Patent ID: 7145045

Claim:
A process for the preparation of an alkanediol, which process comprises: (a) contacting an alkylene oxide with carbon dioxide in the presence of a catalyst to obtain a first liquid reaction mixture containing a cyclic carbonate; (b) optionally removing carbon dioxide and/or alkylene oxide; (c) increasing the pressure of the liquid reaction mixture obtained in step (a) and/or (b); (d) contacting the pressurized first reaction mixture obtained in step (c) with water in the presence of catalyst to obtain a second reaction mixture containing alkanediol and carbon dioxide; (e) separating the second reaction mixture into a liquid effluent and a gaseous effluent containing carbon dioxide; and, (f) recycling at least part of the gaseous effluent containing carbon dioxide to step (a), in which process the pressure in step (d) is higher than the pressure in step (a).