Influence of Support on Catalytic Activity of Ni Catalysts in p-Nitrophenol Hydrogenation to p-Aminophenol

摘要

@@1.Introduction Conventionally, p-aminophenol is produced by iron-acid reduction of p-nitrophenol, which generates large amount of Fe-FeO sludge causing serious pollution problems. Direct hydrogenation of p-nitrophenol catalyzed by Pt, Pd, Ru and Ni is considered as an alternative green process for the production of p-aminophenol. It is well known that nickel is an active and facile catalyst in hydrogenation reaction.However, commercially available Raney Ni catalyst is inclined to catalyze the hydrogenation of aromatic ring, perhaps caused by its micropores. In contrast to Raney Ni catalyst, active metallic nickel present in supported catalysts usually exists in the style of nanosized crystallites, avoiding formation of micropore structure. However, the nature of support affects the performance of active phase, especially for nickel where metal-support interactions are involved [4-5]. In our present work, Kieselguhr-, TiO2-, and Al2O3-supported Ni catalysts were prepared by incipient wetness impregnation method. The supported Ni catalysts were characterized by N2 adsorption/desorption, XRD, TPR, and NH3-TPD. The influence of support on the catalytic activity of Ni in hydrogenation of p-nitrophenol to p-aminophenol was investigated.