Hydrogenation of crotonaldehyde over graphite nanofiber supported nickel

In the current investigation wt: have used the hydrogenation of crotonaldeh yde as a probe reaction in an attempt to follow the changes in catalytic be havior induced by supporting nickel on different types of graphite nanofibe r support materials. The hydrogenation of the alpha,beta-unsaturated aldehy de to the desired product, crotyl alcohol, is a particularly difficult task since there is a strong tendency to hydrogenate both the C=C and C=O bonds in the reactant molecule. This study is designed to compare the catalytic behavior of the metal particles when dispersed on two types of nanofibers, where the orientation of the graphite platelets within the structures is si gnificantly different in each case. The metal crystallites are located in s uch a manner that the majority of particles are in direct contact with grap hite edge regions. For comparison purposes, the same set of hydrogenation r eactions were carried out under similar conditions over gamma-Al2O3 support ed nickel particles. The results demonstrate that when graphite nanofibers are used as a support media for nickel particles, these unusual carbonaceou s materials exert a tremendous impact on the performance of the metal for t he hydrogenation of crotonaldehyde to crotyl alcohol. Possible reasons for this unexpected pattern of behavior are presented. (C) 1999 Elsevier Scienc e B.V. All rights reserved.