Hydroformylation process

A hydroformylation process comprising:

• (a) contacting in a reaction zone reactants comprising an olefin, hydrogen and CO in the presence of a metal hydrolyzable phosphorous ligand complex catalyst and, optionally, free hydrolyzable phosphorous ligand, under reaction conditions sufficient to produce an aldehyde product in a reaction fluid, with the proviso that at least one of the reactants comprises methanol and that the total amount of methanol in the reactants, prior to entering the reaction zone, is from 200 ppm to 10 percent of the total weight of methanol and the reactants,
• (b) removing at least a portion of the reaction fluid from the reaction zone to a separation zone, and separating the reaction fluid in the separation zone to produce a hydroformylation reaction product stream and a catalyst recycle stream,
• (c) treating at least a portion of said catalyst recycle stream with an aqueous buffer solution under conditions sufficient to neutralize and remove at least some amount of one or more phosphorus acidic compounds from said product stream.