Hydroformylation process including catalyst recycle

A process for hydroformylating an olefin feed in the presence of a homogeneous catalyst to form an organic hydroformylation reaction product, the catalyst comprising a carbonyl compound of a first metal which is cobalt, which process comprises:

• (a) performing a first demetalling step (101) comprising contacting the organic cobalt catalyst-containing reaction product (11) with an aqueous solution (1) of a salt of a second metal and a first acid, the first acid having a pKa of at least 1.5 at 25° C., to form an aqueous solution (2) comprising a salt of the second metal having cobalt carbonyl as anion,
• (b) performing a first separation step (102) on the product of step (a) which comprises separating the aqueous solution (2) from the organic hydroformylation reaction product to form an organic reaction product having reduced cobalt content (13),
• (c) performing a second demetalling step (103) comprising contacting the organic reaction product (13) separated in step (b), in the presence of an oxygen-containing gas or an oxygen-donating compound (7), with an aqueous solution (3) of a second acid to form (i) an aqueous solution (4) comprising a cobalt salt of the second acid and (ii) a cobalt-depleted organic reaction product (15), and
• (d) recycling at least part of the aqueous solution (2) separated in step (b) to the hydroformylation reaction (200).