Process for the separation and recovery of rhodium from the products of the oxo synthesis
AssigneeHoechst Aktiengesellschaft
InventorsPeter Lappe, Ludger Bexten, Dieter Kupies
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Abstract
To separate and recover rhodium, the distillation residues of oxo synthesis products are initially treated with an oxidant. Then the reaction mixture is reacted, in the presence of carbon monoxide (or a compound which splits off carbon monoxide), with an aqueous solution of a reagent forming a water-soluble complex compound with rhodium. The reaction mixture breaks into an organic phase and an aqueous phase, the complex goes to the aqueous phase as it is substantially insoluble in the organic phase.
Claims28
A process for the recovery of a rhodium or a rhodium-containing catalyst from a distillation residue of a mixture of oxo synthesis products consisting essentially of reacting the distillation residue with an oxidizing agent to form a mixture, reacting the mixture in the presence of carbon monoxide or a carbon monoxide forming compound with an aqueous solution of a reagent which forms a more stable water soluble but organic media insoluble complex with rhodium than a complex with carbon monoxide, said reagent having the formula ##STR2## wherein Ar.sup.1, Ar.sup.2 and Ar.sup.3 are each a phenyl or naphthyl group;
- Y.sup.1,Y.sup.2,Y.sup.3 each denote a straight or branched chain alkyl group with 1 to 4 carbon atoms, a straight or branched chain alkoxy group with 1 to 4 carbon atoms, a halogen atom, or an OH, --CN, --NO.sub.2, or R.sup.1 R.sup.2 N-- group in which R.sup.1 and R.sup.2 each stand for a straight or branched chain alkyl group with 1 to 4 carbon atoms, X.sup.1, X.sup.2 and X.sup.3 are each a carboxylate (COO--) or a sulfonate (SO.sub.3 --) group;
- m.sub.1, m.sub.2, m.sub.3 are individually integers from 0 to 3, at least one m.sub.1, m.sub.2 or m.sub.3 being equal to or greater than 1;
- and n.sub.1, n.sub.2, n.sub.3 are individually integers from 0 to 5, treating the mixture with an inert organic solvent, recovering the aqueous phase containing the water soluble complex of rhodium and reusing the same as a hydroformylation catalyst.
Dependencies are inferred from the claim text.