Mild and selective hydrogenation of nitriles into primary amines over a supported Ni catalyst

Abstract

The development of new heterogeneous non-noble catalytic systems for the selective hydrogenation of nitriles into primary amines is a challenging task. In this study, a mesoporous Al₂O₃ supported Ni catalyst (denoted as Ni/Al₂O₃-600, where 600 represents the reduction temperature) demonstrated a high catalytic activity for the hydrogenation of nitriles under mild conditions (60–80 °C and 2.5 bar H₂) with ammonia as the additive. This catalytic system has a wide substrate range and the Ni/Al₂O₃ catalyst demonstrated a good tolerance to other functional groups, which was possibly due to its high catalytic activity under mild conditions. A plausible reaction pathway was proposed for the hydrogenation of nitriles into primary amines, and it was found that ammonia played a great role in the enhancement of the selectivity of primary amines by the inhibition of the side reaction to generate secondary amines. In addition, the Ni/Al₂O₃-600 catalyst could be reused five times without activity loss through convenient magnetic recovery.