Reactivation process for water soluble hydroformylation catalysts

摘要

To restore their effectiveness, deactivated, water-soluble hydroformylation catalysts containing rhodium and sulphonated or carboxylated arylphosphines, are admixed with maleic acid, fumaric acid or olefinically unsaturated compounds of the general formula in which X represents O, S, N-R<5> or P-R<5> and R<3>, R<4> and R<5> are identical or different and mean hydrogen, an alkyl radical or an aryl radical.