Process for recovering triarylphosphine from poisoned rhodium catalyst systems

摘要

A process for recovering re-usable triarylphosphine (e.g. triphenylphosphine) from rhodium catalyst residues poisoned by the presence of alkyldiarylphosphine (e.g. n-propyldiphenylphosphine) such as are obtained as spent catalyst residues from the hydroformylation of olefins. The process comprises subjecting the poisoned residues to evaporative separation under reduced pressure to separate a vapor comprising triarylphosphine from the rhodium and then mixing the condensed vapor with polar solvent and obtaining the triarylphosphine as a crystalline precipitate from the solvent. The crystalline phosphine is sufficiently free of poisons to be re-usable as a catalyst component in a hydroformylation process.