VAPOR-PHASE PROPENE HYDROFORMYLATION CATALYZED BY THE RH/AL SYSTEM ON SILICA

A Rh/Al system with rhodium nanocrystals was prepared by reducing rhodium trichloride supported on silica with lithium aluminum hydride at low temperature in THF. After pretreatment in Ar and in CO/H-2 the system was found to be an active catalyst of vapour phase propene hydroformylation at atmospheric pressure. The nature and composition of the active surface was studied by X-ray diffraction, X-ray photoemission spectroscopy (XPS) and Fourier transform-IR spectroscopy. Regioselectivity and chemoselectivity data are correlated to the proposed nature and morphology of the active sites of the catalyst derived from spectroscopic data. The Rh/Al system is compared with the Rh/B system we described in preceding papers.