Process for purifying and recovering contaminated catalyst solution

Abstract

The disclosure relates to a process for purifying and recovering a contaminated catalyst solution which is obtained in the carbonylation of methyl acetate and/or dimethylether, the catalyst solution containing carbonyl complexes of noble metals of group VIII of the Periodic System of the elements, quaternary heterocyclic aromatic nitrogen compounds or quaternary organophosphorus compounds as organic promoters, and optionally compounds of carbonyl-yielding common metals as inorganic promoters, undistillable organic contaminants as well as acetic acid, acetic anhydride and ethylidene diacetate. To this end, the disclosure provides for the catalyst solution to be distillatively freed from its volatile constituents and for the remaining solid distillation residue to be freed from the organic contaminants by extraction with aliphatic ethers; and for the remaining undissolved mixture of noble metal/carbonyl-complex, organic and optionally inorganic promoters to be filtered off and recycled into the carbonylation reaction.