Influence of Phosphine Concentration on Propylene Hydroformylation over the PPh3-Rh/SiO2 Catalyst

The effect of triphenyl phosphine concentration in the novel PPh3-Rh/SiO2 catalyst for propylene hydroformylation was studied and found an optimum P/Rh ratio of 15, a butyraldehyde till ratio of 14, a butyraldehyde TOF of 241 h(-1), and high catalytic stability for PPh3-Rh/SiO2. Solid-state P-31 NMR shows that in an atmosphere of syngas the physically adsorbed PPh3 migrates onto the surface of Rh/SiO2 where it chemically adsorbs and then promotes the in situ formation of carbonyl phosphine complexes