Formate formation during Co2(CO)8/PR3-catalyzed hydroformylation

Article abstract of DOI:10.1021/om00079a030

Careful examination of phosphine-modified cobalt hydroformylation (2000 psig, CO/H₂ = 1:2, 190°C, Co/P = 1:1) as a function of PR₃ reveals that moderate selectivity to formates can be achieved depending on the cone angle of the PR₃ ligand chosen. These results are rationalized in terms of a stabilization or destabilization of a carboalkoxycobalt intermediate. Formate yields as high as 46% have been achieved with PEt₃ at 4000 psig. The organometallic species present in the reaction are examined in detail for Co₂(CO)₈/PR₃ (PR₃ = PCy₃, PEt₃, and PPh₃) by ³¹P NMR and IR spectroscopy.