Process for the purification of crude propene oxide
AssigneesDegussa AG, Uhde GmbH
InventorsWilli Hofen, Thomas Haas, Wolfgang Woll, Georg Thiele
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Abstract
A process for the purification of a crude propene oxide containing methanol and acetaldehyde by a continuously operated extractive distillation using an extraction solvent lowering the volatility of methanol and feeding a compound containing an unsubstituted NH2 group capable of reacting with acetaldehyde to a distillation column at a point above the feeding point of the crude propene oxide to give a purified propene oxide containing less than 100 ppm methanol and less than 100 ppm acetaldehyde. There is also disclosed a process for the catalytic epoxidation of propene that includes this purification stage.
Claims20
A process for the purification of a crude propene oxide containing methanol and acetaldehyde by a continuously operated extractive distillation in a distillation column having a feeding point for the crude propene oxide, comprising:
- a. feeding an extraction solvent to the distillation column at a point of said column above the feeding point of the crude propene oxide in an amount effective for lowering the volatility of methanol relative to the volatility of propene oxide,
- b. feeding a compound containing an unsubstituted NH2 group and capable of reacting with acetaldehyde under the conditions of distillation to form compounds with a boiling point higher than that of propene oxide to the distillation column at a point above the feeding point of the crude propene oxide or admixing said compounds with the crude propene oxide feed to the distillation column and
- c. withdrawing a purified propene oxide from the distillation column at a position above feeding points of the extraction solvent and the compound containing an unsubstituted NH2 group.
Dependencies are inferred from the claim text.