Selective hydrogenation of stearonitrile over Ni-B/SiO2 amorphous catalysts in comparison with other Ni-based catalysts

A series of Ni-B/SiO2 amorphous catalysts were prepared by chemical reducti on; these were employed in the liquid phase selective hydrogenation of stea ronitrile. In comparison with other Ni-based catalysts, such as the corresp onding crystallized Ni-B/SiO2, the Ni/SiO2 obtained by hydrogen reduction a t 673 K, and even the commercially available Raney Ni, the as-prepared Ni-B /SiO2 amorphous catalyst exhibited higher activity and better selectivity t o primary amine; this can mainly be attributed to the promoting effect of i ts amorphous structure and to alloying B. With the increase of Ni loading, both the activity and the selectivity increased. It was also found that NH3 additive in the reaction media was favorable for the production of primary amine, though the reaction activity was slightly inhibited. However, no si gnificant promoting effect of KNO3 doped SiO2 was observed. Such results we re discussed based on various characterizations, including BET, XPS, XRD, I CP, SEM, and NH3-TPD. (C) 1999 Elsevier Science B.V. All rights reserved.