Efficient hydrogenation of aliphatic acyclic amides to amines by bimetallic NiMo nitrides via heterogeneous catalysis

Primary amines are vital building blocks in pharmaceutical and polymer industry. The heterogeneous catalytic hydrogenation of aliphatic acyclic amides to amines is rather attractive but challenging due to low reactivity of aliphatic acyclic amides, and then rarely be reported. Herein, cheap bimetallic NiMo nitride catalysts were synthesized by hydrothermal method and firstly utilized to the efficient conversion of a wide range of aliphatic acyclic amides to amines, achieving 93.9 % conversion of hexanamide and 75.1 % yield to hexylamine. Characterizations such XRD, N2 Physical adsorption, TGA, Raman, XPS, SEM-EDX Mapping and (HR)TEM revealed that Ni2Mo3N is crucially important for the activation of hexanamide while the synergetic effect between Ni2Mo3N and Ni6Mo6C1.06 would further promote the conversion of hexanamide, and higher TOFs (145.9 h−1) and lower Ea (29.5 kJ mol−1) are achieved. The CO bond of the amide can be activated by the surface Lewis acid site of bimetallic NiMo nitrides, while the simultaneous dissociation of H2 to form H atoms is beneficial for hydrogenation. This catalyst is also found to be recyclable with stable catalytic performance upon consecutive runs. The present work provides a novel and unique option for the efficient conversion of aliphatic acyclic amides to amines, being a strong supplementary to those reported for the hydrogenation of cyclic-amides, secondary amides, and tertiary amides.