The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 26, 1991
Filed:
Mar. 09, 1990
Heinz Erpenbach, Cologne, DE;
Winfried Lork, Erftstadt, DE;
Norbert Weferling, Hurth, DE;
Peter Prinz, Hurth, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A process for purifying and recovering the contaminated catalyst solution arising from the carbonylation of methanol, methyl acetate and/or dimethyl ether. The solution contains carbonyl complexes of rhodium, quaternary organophosphorus compounds as organic promoters, undistillable organic impurities, and acetic acid, acetic anhydride and ethylidene diacetate. The carbonyl complex of rhodium together with acetic acid, acetic anhydride and ethylidene diacetate are extracted from the contaminated catalyst solution by using a tri-C.sub.3 - to C.sub.8 -alkylphosphine. The trialkylphosphine phase is separated from the promoter phase and is separated into the volatile constituents acetic acid, acetic anhydride and ethylidene diacetate as well as trialkylphosphine. The rhodium carbonyl complex remaining as the residue and the recovered trialkylphosphine is used for further extraction. The contaminated promoter phase is freed of the organic impurities by extraction with dialkyl ethers, carboxylic acid esters or hydrocarbons and, after the extractant phase has been separated off, is recombined with the recovered acetic acid/acetic anhydride and ethylidene diacetate mixture and with the rhodium carbonyl complex and recycled to the carbonylation reactor. The impurities remaining as the residue from a distillation of the extractant phase which has been separated off are removed from the system.