Selective hydrogenation of cinnamaldehyde to cinnamyl alcohol over mesoporous carbon supported Fe and Zn promoted Pt catalyst

The effect of Fe and Zn promotion on the performance of Pt-based catalysts towards the selective hydrogenation of cinnamaldehyde to the corresponding semi-hydrogenated alcohol was studied using a synthetic carbon xerogel as catalyst support. The promoted and unpromoted catalysts were fully characterised in order to correlate the corresponding properties with catalytic behaviour. The addition of Zn or Fe to the Pt catalyst was found to improve the activity as well as the selectivity to cinnamyl alcohol. The simultaneous use of both promoters enabled to achieve a remarkably high selectivity along with high conversion; promoting effects of Fe and Zn towards selectivity seem to be additive. The important promoting effects observed were explained by the creation of new sites for the activation of the carbonyl group in the cinnamaldehyde molecule and by the development of electronic and stereo-hindrances. The carbon surface chemistry was also found to have a large influence on the catalytic properties. (c) 2008 Elsevier B.V. All rights reserved.