Nickel supported on porous silica as catalysts for the gas-phase hydrogenation of acetonitrile

A series of nickel supported on different porous silica catalysts (5 wt% Ni) were prepared by incipient wetness impregnation. The catalysts were characterized by XRD, H-2-TPR, N-2 adsorption at 77 K, chernisorption of H-2, and IR spectroscopy after CO and CH3CN adsorption. Preliminary experiments have shown that the choice of nickel citrate instead of nickel nitrate as impregnation salt allows high degrees of nickel dispersion to be obtained. The catalytic behavior of this family of nickel-based catalysts reveals that the acid-basic properties of support seem to be more crucial than the extent of specific surface area and the metal particle size in determining the catalytic behavior. Thus. when nickel is supported oil less acidic supports, the formation of higher amines (diethylamine and triethylamine) by condensation reactions is negligible, and full acetonitrile conversion and yields of ethylamine higher than 80 mol% at 408 K are reached. (C) 2004 Elsevier Inc. All rights reserved.