Highly efficient electrochemical hydrogenation of acetonitrile to ethylamine for primary amine synthesis and promising hydrogen storage

Selective nitrile hydrogenation to valuable primary amines under mild conditions is still a great challenge. Herein, we report the synergistic effect of a Cu catalyst and dissolved CO2 to electrochemically hydrogenate acetonitrile to ethylamine with a high selectivity (99%) and faradic efficiency (94%) in an aqueous electrolyte, superior to the best performance reported to date. The results show that a Cu catalyst offers preferential adsorption of the nitrile on the surface through the terminal C N group, facilitating the hydrogenation process on this site while suppressing the side reactions. The CO2 in the electrolyte protects the initially formed primary amine by reacting with the NH2 group, preventing it from condensing into amine dimers and trimers. Importantly, the method can be further extended to other aliphatic nitriles with functional groups, including carboxyl, hydroxyl, and cycloalkane, while exciting selectivity (>90%) of the corresponding primary amines was also obtained.