A catalyst for use in hydroformylation of olefins which comprises a Group VIII noble metal complexed with a phosphine ligand having at least one alkyl or aryl group bonded thereto, such as tris-4-propylphenyl phosphines and tris-4-octylphenyl phosphines. These and other triphenylphosphine catalysts can be separated from a crude reaction product of a noble metal-catalyzed hydroformylation reaction by contacting the crude reaction product with a dense polymeric, nonpolar membrane, preferably nonpolar polyolefin membranes.