| 摘要 |
The invention provides a process for the preparation of alkanediol comprising the steps: (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<SUB>2</SUB>CO<SUB>3</SUB>; (iii) subjecting the second reaction mixture containing alkanediol and R<SUB>2</SUB>CO<SUB>3 </SUB>to a separation step to yield a crude alkanediol stream, which is subjected to distillation to yield a purified stream of alkanediol as the 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 and/or with at least part of the purified alkanediol stream.
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