Recovery of transition metals from aqueous solutions
AssigneeShell Oil Company
InventorsBrian L. Goodall, Paulus A. M. Grotenhuis
Life of this patent
Estimating the term…
Abstract
Process for the recovery of a transition metal from an aqueous solution containing a complex of the transition metal with a cyclic phosphite by hydrolyzing the cyclic phosphite, contacting the hydrolysis reaction mixture with a compound forming a water-stable complex with the transition metal, extracting the reaction mixture thus formed with an organic extraction agent for the water-stable complex and separating an organic extract phase containing the transition metal from an aqueous raffinate phase. The process is particularly suitable for the recovery of the Rh or Co from spent hydroformylation catalysts and of Pd from spent carbonylation catalysts.
Claims14
A process comprising recovering a transition metal from an aqueous solution containing a complex of said transition metal with a cyclic phosphite having a bridgehead phosphorus atom linked to three oxygen atoms at least two of which form together with the bridgehead phosphorus atom part of a ring, said cyclic phosphite having a hydroxymethyl group linked to a ring carbon atom, by:
- (a) hydrolyzing the cyclic phosphite in said complex, thereby forming a reaction mixture,
- (b) contacting the reaction mixture obtained in step (a) with a compound forming a water-stable complex with said transition metal which is sufficiently water-stable to preclude the need to distill off water in order to achieve substantially complete recovery of said transition metal.
- (c) contacting the reaction mixture obtained in step (b) with an organic extraction agent for said water-stable complex, thereby forming an organic extract phase containing at least a portion of said transition metal, and an aqueous raffinate phase, and
- (d) separating said organic extract phase containing at least a portion of said transition metal from said aqueous raffinate phase.
Dependencies are inferred from the claim text.