Supported homogeneous film catalysts are described which, in effect, heterogenize biphasic systems. Water-soluble catalysts are added to hydrophilic films, e.g., polyethylene glycol 600, to catalyze the reactions of hydrophobic substrates. Activities are obtained for the hydroformylation of 1-hexene equal to those obtained in homogeneous systems. Experiments are described that indicate that the reactions are occurring in the homogeneous film dispersed over the solid support. (C) 1995 Academic Press, Inc.