Liquid phase hydrogenation of adiponitrile over directly reduced Ni/SiO2 catalyst

Liquid phase hydrogenation of adiponitrile (ADN) to 6-aminocapronitrile (ACN) and hexamethylenediamine (HMD) was investigated on Ni/SiO2 catalysts prepare under different conditions. In this reaction, the highly reactive imine intermediate forms condensation by products by reacting with the primary amine products (ACN and HMD). A highly dispersed Ni/SiO2 catalyst prepared by the direct reduction of Ni(NO3)(2)/SiO2 was found to suppress the condensation reactions by promoting the hydrogenation of adsorbed imine, and it gave excellent hydrogenation activity and primary amine selectivity. Addition of NaOH increased the primary amine selectivity to 79% at the ADN conversion of 86%. (C) 2015 Elsevier B.V. All rights reserved.