PROCESS FOR REMOVING METALLIC CORROSION PRODUCTS FROM A CONTAMINATED CATALYST SOLUTION PRODUCED ON CARBONYLATION OF METHANOL AND/OR METHYL ACETATE AND/OR DIMETHYL ETHER

摘要

In the process for removing metallic corrosion products from a contaminated catalyst solution which arises in the carbonylation of methanol and/or methyl acetate and/or dimethyl ether and which contains carbonyl complexes of rare metals from group VIII of the periodic table of the elements, quaternary organophosphorus compounds as organic promoters, metallic corrosion products and also acetic acid, acetic anhydride, ethylidene diacetate and, in some cases, undistillable organic compounds, the catalyst solution is treated with water, the rare metal carbonyl complex and, if appropriate, the undistillable organic compounds being precipitated, while the organic promoter and the metallic corrosion products remain in solution; the aqueous phase is separated from the precipitated rare metal carbonyl complex and the organic promoter is extracted from the aqueous phase with C4-C8-alkanols, the promoter is recovered by evaporation of the extractant, the promoter is recombined with the precipitated rare metal carbonyl complex and, if appropriate, with the undistillable organic compounds and, after the addition of acetic acid and/or acetic anhydride, the purified catalyst solution is recycled to the process; finally, the aqueous phase with the metallic corrosion products is removed from the system.