Process for purifying and recovering contaminated catalyst solution obtained in the carbonylation of methyl acetate and/or dimethylether

US4629711A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Heinz Erpenbach · Cologne, DE
• Klaus Gehrmann · Lechenich, DE
• Winfried Lork · Lechenich, DE
• Peter Prinz · Ethel, US

Key dates

• Filing date: Apr 15, 1986
• Grant date: Dec 16, 1986
• Expiry date: Apr 15, 2006

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/584
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Catalyst solution contaminated during the carbonylation of methyl acetate and/or dimethylether, containing carbonyl complexes of rhodium, quaternary heterocyclic aromatic nitrogen compounds or quaternary organophosphorus compounds as organic promoters, undistillable organic contaminants, acetic acid, acetic anhydride and ethylidene diacetate, is purified and recovered. To this end the contaminated catalyst solution is extracted with a dialkylether having from 1-4 carbon atoms and thereby freed from its organic contaminants, acetic acid, acetic anhydride and ethylidene diacetate, and the ether phase is separated from a precipitated promoter-containing catalyst complex; the ether phase is treated with iodine and/or methyl iodide, a further portion of precipitated promoter-containing catalyst complex is separated and united with the purified catalyst complex; the ether phase is distillatively separated into its constituents, recovered dialkylether is used for extraction, and fresh catalyst solution is prepared from the recovered mixture of acetic acid, acetic anhydride and ethylidene diacetate and united purified catalyst complex, and the organic contaminants retained in the residue c…