Method for recovering and recycling catalyst constituents

摘要

Catalytic materials including divalent palladium compounds, divalent cobalt compounds and bromide sources such as tetraalkylammonium and hexaalkylguanidinium bromides are removed from organic carbonylation reaction mixtures comprising said materials in combination with diaryl carbonate and hydroxyaromatic compound. The removal steps include extraction with an aqueous complexing solution for palladium, extraction with an aqueous non-basic and preferably ionic extractant for cobalt, and extraction with water to remove bromide source. These steps may be combined into an integrated process. Further steps of recycle of the palladium by reduction to elemental palladium and conversion to a catalytically active species, and conversion of cobalt to a catalytically active species, may be included in the integrated process.