Hydroformylation process

Claim 1

In a process for hydroformylating an alphaolefin containing 2 to 20 carbon atoms to produce aldehydes having one more carbon atom than the alpha-olefin by reacting the alpha-olefin with hydrogen and carbon monoxide in a liquid reaction medium which contains a soluble rhodium complex catalyst consisting essentially of rhodium complexed with carbon monoxide and a triarylphosphine ligand, and in the presence of free triarylphosphine, the improvement comprising improving the stability of the catalyst by charging the liquid reaction medium containing the catalyst with from about 0.1 to 20 percent by weight of an alkyldiarylphosphine ligand based on the total weight of the liquid reaction medium, and controlling the reaction conditions to a temperature of from about 100° to about 140° C., a total gas pressure of hydrogen, carbon monoxide and alpha-olefin of less than about 450 pounds per square inch absolute, carbon monoxide partial pressure of less than about 55 pounds per square inch absolute, a hydrogen partial pressure of less than about 200 pounds per square inch absolute, and at least about 75 moles of total free phosphine ligand for each mole of catalytically-active rhodium metal present in the rhodium complex catalyst which consists essentially of rhodium complexed with carbon monoxide and one or both of said triarylphosphine and said alkyldiarylphosphine.