Catalyst preparation process

A process comprising (A) forming a hydroformylation catalyst by contacting under reaction conditions, in the presence of a solvent, a catalytic metal precursor, at least one organopolyphosphite ligand, CO, hydrogen, a bulky organomonophosphite ligand and, optionally, an olefin, wherein:

• the molar organopolyphosphite-to-catalytic metal ratio is greater than 1 but less than 2;
• the partial pressure of carbon monoxide is at least 25 psig;
• and the molar ratio of bulky organomonophosphite-to-catalytic metal is from 5:1 to 50:1;
• and then (B) allowing the organopolyphosphite ligand concentration to diminish such that the ratio of organopolyphosphite ligand-to-catalytic metal falls to less than 1, wherein the contacting is conducted such that the bulky organomonophosphite is introduced at the same time or after the organopolyphosphite ligand.