Recovery of rhodium from rhodium complexes, for reuse as a hydroformylation catalyst, comprises extraction with a phosphate or phosphonate, oxidization and treatment with an arylphosphine.

摘要

Recovery of rhodium from rhodium complexes comprises: (i) extraction of the organic phase with an aqueous solution of a phosphate or phosphonate; and (ii) treating the organic phase with an oxidizing agent and with an aqueous solution of an arylphosphine at increased temperature and pressure to recover the rhodium-containing aqueous solution from the organic phase. A process for the recovery of rhodium from rhodium complexes, optionally cobalt complexes and optionally complex ligand-containing organic solutions comprises: (i) extraction of the organic phase with an aqueous solution of a phosphate of formula (1) or phosphonate of formula (2); (ii) washing the organic phase with water at pH 0-8; (iii) treating the organic phase with an oxidizing agent at 0-100 [deg]C; (iv) treating the organic phase with an aqueous solution of a water-soluble arylphosphine at increased temperature and pressure; and (v) phase separation of the rhodium containing aqueous solution (I) from the organic phase. (O)P(OR1>)(OR2>)(OR3>) (1) R4>P(O)(OR5>)(OR6>) (2) R1>-R6>H, 1-10C alkyl or 6-10 C aryl, optionally substituted with 1-4C alkyl. Independent claims are also included for: (i) A catalyst for hydroformylation of aldehydes, comprising the recovered aqueous rhodium-containing solution (I) (ii) A process for the treatment of the recovered rhodium-containing aqueous solution (I) at 50-200 [deg]C and 0.1-2.0 MPa with an oxidizing agent followed by extraction using an organic (di)phosphine-containing organic solvent. (iii) The recovered rhodium-containing organic solution (II).