Hydroformylation process

Abstract

The invention relates to a process for the preparation of aldehydes by the hydroformylation of olefinically unsaturated compounds using a rhodium catalyst which catalyst is provided by (1) introducing rhodium into the reaction solution in the form of an ionic rhodium compound, the said ionic compound consisting of (a) a rhodium-containing cation having rhodium complexed with ligands other than halide, and (b) a non-coordinating anion; and (2) furnishing to the reaction solution at least two moles of a modifying ligand per mole of ionic rhodium compound where the modifying ligand is furnished either pre-coordinated in the said ionic rhodium compound or as a free compound, and where the modifying ligand is a tertiary organo phosphorous compound having from 3 to 90 carbon atoms, or a tertiary organo arsenic compound having from 3 to 90 carbon atoms, or a tertiary organo antimony compound having from 3 to 90 carbon atoms. The process is especially useful for the production of aldehydes from olefinically unsaturated compounds having from 2 to 30 carbon atoms, carbon monoxide, and hydrogen at a total pressure of from 4.6 to 142 kg/cm.sup.2 (50 to 2,000 psig), and at a temperature of from about 60.degree. C to about 180.degree. C. A preferred embodiment of the invention utilizes the modifying ligand at a molar concentration in excess of that required stoichiometrically by the ionic rhodium compound. Another preferred embodiment of this invention employs the modifying ligand as the solvent for the reaction system.