Patent ID: 7342141

Claim:
A process for the preparation of alkanediol comprising: (i) contacting alkylene oxide with carbon dioxide in the presence of a carbonation catalyst to obtain a reaction mixture containing alkylene carbonate at a reaction temperature of from 100 to 200° C.; (ii) contacting the reaction mixture obtained in step (i) with R—OH, in which R is hydrogen or an alkyl group in the presence of a catalyst to obtain a second reaction mixture containing alkanediol and R 2 CO 3 ; (iii) subjecting the second reaction mixture containing alkanediol and R 2 CO 3 to a separation step to yield a crude alkanediol stream, which is subjected to distillation to yield a purified stream of alkanediol as a bottom stream; (iv) subjecting the purified stream of alkanediol obtained in step (iii) to further distillation to obtain a second bottom stream containing a mixture of alkanediol, heavy components, and optionally carbonation catalyst, and a top stream containing high purity alkanediol; wherein at least part of the reaction mixture obtained in step (i) is used for heat exchange with at least part of the crude alkanediol stream or with at least part of the purified alkanediol stream.