Process for hydroformylation of olefin hydrocarbons

In the process for the hydroformylation of olefin hydrocarbons of 2 to about 16 carbon atoms the improvement which comprises conducting said hydroformylation in contact with a catalyst composition consisting of a major amount of a solid, sodium form crystalline alumino-silicate support, said crystalline aluminosilicate support having a silicato alumina mole ratio of from about 2:1 to 12:1, a sodium oxide-to-alumina mole ratio of from about 0.7:1 to 1.1:1 and pore diameters of from about 6 to 15 Angstroms, and a minor amount of providing about 0.2 to about 0.6 weight per cent rhodium, said rhodium composition having a mole ratio of ligand to metal of about 1.5:1to 3:1, said ligand being R.sub.3 P in which each R is independently selected from the group consisting of phenylalkyl, alkylphenyl, phenyl, and alkyl groups having from 2 to about 16 carbon atoms.