Selective hydrogenation of alpha-, beta-unsaturated aldehyde to unsaturated alcohol with supported platinum catalysts at high pressures of hydrogen

Hydrogenation of an ct, P-unsaturated aldehyde, cinnamaldehyde (CAL), was c arried out with silica-supported platinum catalysts in ethanol under pressu rized hydrogen atmosphere up to 12 MPa at 50 degreesC. The initial rate of reaction (CAL consumption) was proportional to hydrogen pressure and indepe ndent of CAL concentration. Increasing hydrogen pressure decreased the sele ctivity of cinnamyl alcohol (COL) but increased that of hydrocinnamaldehyde (HCAL). The COL selectivity increased with CAL concentration. The effect o f hydrogen pressure on the selectivity in ethanol is different from that ob served previously in a solvent of supercritical carbon dioxide. (C) 2001 El sevier Science B.V. All rights reserved.