Process for preparing dialkyl carbonate and alkanediol
AssigneeShell USA, Inc.
InventorsEvert Van Der Heide, Kai Jürgen Fischer
Life of this patent
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Abstract
The invention relates to a process wherein a dialkyl carbonate stream containing an ether alkanol impurity is subjected to extractive distillation using an extraction solvent to obtain a top stream comprising dialkyl carbonate and a bottom stream comprising the ether alkanol impurity and the extraction solvent, wherein the extraction solvent is an organic compound containing one or more ester moieties and/or ether moieties which organic compound does not contain a hydroxyl group. Further, the invention relates to a process for making a diaryl carbonate, comprising reacting an aryl alcohol with a stream containing a dialkyl carbonate from which stream an ether alkanol impurity has been removed in accordance with the above-described process.
Claims11
Process for the preparation of a dialkyl carbonate and an alkanediol, comprising:
- (a) reacting an alkylene carbonate and an alkanol to obtain a product mixture containing unconverted alkylene carbonate, unconverted alkanol, dialkyl carbonate, alkanediol and an ether alkanol impurity;
- (b) separating unconverted alkylene carbonate and alkanediol from the product mixture to obtain a top stream containing unconverted alkanol, dialkyl carbonate and the ether alkanol impurity;
- (c) recovering the alkanediol;
- (d) separating unconverted alkanol from the top stream obtained in step (b) to obtain a bottom stream containing dialkyl carbonate and the ether alkanol impurity;
- and
- (e) subjecting the bottom stream obtained in step (d) to extractive distillation using an extraction solvent to obtain a top stream comprising dialkyl carbonate and a bottom stream comprising the ether alkanol impurity and the extraction solvent, wherein the extraction solvent is an organic compound containing one or more ester moieties and/or ether moieties which organic compound does not contain a hydroxyl group;
- and
- (f) removing the ether alkanol impurity from the bottom stream obtained in step (e) and recycling the extraction solvent to step (e).
Process for removing an ether alkanol impurity from a stream containing a dialkyl carbonate and the ether alkanol impurity, comprising:
- (e) subjecting the stream containing a dialkyl carbonate and the ether alkanol impurity to extractive distillation using an extraction solvent to obtain a top stream comprising dialkyl carbonate and a bottom stream comprising the ether alkanol impurity and the extraction solvent, wherein the extraction solvent is an organic compound containing one or more ester moieties and/or ether moieties which organic compound does not contain a hydroxyl group;
- and
- (f) removing the ether alkanol impurity from the bottom stream obtained in step (e) and recycling the extraction solvent to step (e).
Dependencies are inferred from the claim text.