New approach to skeletal nickel catalysts catalytic properties of the nickel-chromium system

Abstract

A series of chromium doped Raney nickel were prepared from Ni 2_xCr xAl 3precursor alloy (x = 0.07 and 0.11) which were either crystalline or microcrystalline. These catalysts were studied during the hydrogenation of carbonyl or ethylenic groups (acetophenone, cyclohexene, crotonaldehyde, and 1,2,3,6-tetrahydrobenzaldehyde). Modification of the activity depended principally on the amount of chromium present and, to a minor degree, on the homogeneity or on the state of crystallization of the starting alloy. The correlation obtained between the catalytic properties and the amount of Cr III on the surface allowed us to propose a promoting effect for specific amounts of chromium oxide. Residual metallic aluminium would seem to play an inhibiting role, but this has yet to be confirmed.