Hydroformylation process

In an improved process for the production of aldehydes, by the reaction of a olefinically insaturated hydrocarbon 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, and at a temperature of from about 60.degree. C to about 180.degree. C, the improvement which comprises contacting the said reactants in the presence of a solution of a rhodium catalyst, in which said 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 comlexed with ligands selected form the group consisting of:

• mono-enes of 2 to 12 carbon atoms,
• dienes of 4 to 12 carbon atoms,
• trienes of 6 to 16 carbon atoms,
• alkynes of 2 to 12 carbon atoms,
• ketones of 3 to 12 carbon atoms,
• nitriles of 2 to 12 carbon atoms,
• N-alkylamides of 2 to 12 carbon atoms,
• N,n-dialkylamides of 3 to 12 carbon atoms,
• sulfoxides of 2 to 12 carbon atoms,
• tertiary phosphines and phosphites of 3 to 90 carbon atoms,
• tertiary arsines and arsenites of 3 to 90 carbon atoms,
• tertiary stibines and stibites of 3 to 90 carbon atoms,
• carbon monoxide, and combinations thereof,
• and (b) BPh.sub.4.sup.- ;
• 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 selected from the group consisting of tertiary phosphines and phosphites, arsines and arsenites, stibines, and stibites, having from 3 to 90 carbon atoms.