Abstract: Improved oxo process for preparing higher alcohols by hydrolyzing prior to hydrogenation a demetalled hydroformylation reaction product in the presence of an alumina catalyst having a surface area between 40 to about 60 m.sup.2 /g.

Abstract: Certain triarylphosphine rhodium carbonyl hydride complexes(Ar.sub.3 P).sub.3 Rh(CO)H (I) and (Ar.sub.3 P).sub.2 Rh(CO).sub.2 H (II)are selective and stable catalysts of high temperature olefin hydroformylation. The critical factors are the maintenance of a sufficient CO partial pressure, above 25 psia, and the provision of a high excess of triarylphosphine ligand concentration, at a minimum of 1 mole per kg. To provide a high ratio of n- to i-aldehyde products of 1-olefin hydroformylation, the concentration of the tris-phosphine complex (I) is maximized. In a continuous product flashoff operation of the present process, the major high boiling solvent components are the excess phosphine ligands and monoalcohol and monoester by-products.A combined isomerization-hydroformylation process is also disclosed for the selective conversion of internal linear olefins to terminal n-aldehydes. In this process, the concentration of the bis-phosphine complex (II) is minimized.