Hydrogenation of crotonaldehyde over graphite nanofiber supported nickel

In the current investigation wt: have used the hydrogenation of crotonaldehyde as a probe reaction in an attempt to follow the changes in catalytic behavior induced by supporting nickel on different types of graphite nanofiber support materials. The hydrogenation of the alpha,beta-unsaturated aldehyde 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 significantly different in each case. The metal crystallites are located in such a manner that the majority of particles are in direct contact with graphite edge regions. For comparison purposes, the same set of hydrogenation reactions were carried out under similar conditions over gamma-Al2O3 supported nickel particles. The results demonstrate that when graphite nanofibers are used as a support media for nickel particles, these unusual carbonaceous materials exert a tremendous impact on the performance of the metal for the hydrogenation of crotonaldehyde to crotyl alcohol. Possible reasons for this unexpected pattern of behavior are presented. (C) 1999 Elsevier Science B.V. All rights reserved.