Continuous Hydrogenation of Nitriles to Primary Amines with High Selectivity in Flow by Using Raney Cobalt

Abstract

Primary amines produced by selective catalytic hydrogenation of cyano compounds are widely used as basic chemicals, but due to the complexity of the hydrogenation mechanism and the inefficient mass transfer of the intermittent reaction, the process tends to produce secondary and tertiary amines as undesirable by‐products. In this research, a continuous hydrogenation system employing a micropacked‐bed reactor (μPBR) was established for the catalytic hydrogenation of 3‐ethylaminopropionitrile (3‐EAPN) to synthesize N‐ethyl‐1,3‐propanediamine (3‐EAPA). Under optimal experimental conditions using Raney cobalt as a catalyst, complete conversion of 3‐EAPN was achieved, and a high selectivity of 99.6 % for the primary amine (3‐EAPA) was obtained. On this basis, the system was extended with other cyano compounds of different structures as hydrogenation substrates, demonstrating the general applicability of this continuous hydrogenation system by using Raney cobalt as a catalyst in a μPBR for the hydrogenation of various nitriles.