PROCESS FOR THE PRODUCTION OF DIALKYL CARBONATE AND ALKANEDIOL

摘要

An alkylene carbonate and an alkanol are subjected to transesterification to yield a dialkyl carbonate and alkanediol in a process comprising (a) introducing the alkylene carbonate and an alkanol feedstock into a reaction zone to react in the presence of a transesterification catalyst to yield an alkanediol-rich stream and a stream comprising dialkyl carbonate and alkanol, which streams are separated; (b) passing the stream comprising dialkyl carbonate and alkanol to an extractive distillation zone in which an extractant is added to the stream; (c) obtaining from the extractive distillation zone an alkanol-rich vapor stream and a bottom stream containing the extractant and the dialkyl carbonate; (d) separating the bottom stream from step (c) in a second non-extractive distillation zone to yield a dialkyl carbonate-rich top stream and a extractant-rich bottom stream; and (e) at least partly recycling the extractant-rich bottom stream to the extractive distillation zone, wherein the extractant-rich bottom stream is used as heat source for the alkanol feedstock.