DE3026900

This invention relates to a process for dual demetalling of an oxo product contaminated with cobalt-containing catalyst residues and recovering catalytically active cobalt carbonyls which comprises treating the oxo product in a first zone with an aqueous solution of a cobalt salt of an organic or inorganic acid to extract cobalt carbonyl partially from the oxo product into the aqueous phase containing Co++ ions to form Co[Co(CO)4]2 therein and in a second zone substantially completing the demetalling of the thus treated oxo product by treatment with an aqueous organic or inorganic acid in the presence of air or oxygen to form a Co++ salt and using the resulting aqueous solution as feed to the first zone; subjecting the aqueous phase obtained from the first zone to preforming in a high pressure preformer under synthesis gas to convert any excess or residual Co++ salt contained in said aqueous phase to Co[Co(CO)4]2 and extracting cobalt carbonyls from the aqueous phase with an organic solvent, the organic solvent extract being recycled to the oxo reactors as catalyst.