Electrohydrogenation of Benzonitrile into Benzylamine under Mild Aqueous Conditions

The electrohydrogenation of benzonitrile to benzylamine was investigated by using copper and copper−silver electrodes under mild conditions and moderate current density. In this study, we optimized several reaction parameters, including solvent, current density applied, electrolyte effect, and substrate concentration. The results reveal that the best performance in terms of yield, conversion, and faradaic efficiency was obtained at −20 mA·cm−2, using copper−silver electrodes, at neutral pH (0.5 M KCl). Our study highlights the potential of electrochemistry to enhance reduction reactions by electrohydrogenation using only water as the proton source and demonstrates the potential of copper−silver electrodes for efficient and environmentally friendly
electrochemical hydrogenation at neutral pH. Additionally, our research aims to emphasize the capability of electrocatalysis to undergo reversible electrohydrogenation/dehydrogenation transformations using the nitrile/amine pair as a promising candidate in the field of hydrogen storage as liquid organic hydrogen carriers. This study not only provides insights into the possibility of
sustainable hydrogenation processes but also contributes to further exploration of electrocatalytic systems for scalable, efficient, and environmentally friendly hydrogen storage solutions, such as the nitrile/amine pair.

KEYWORDS: electrochemical hydrogenation, benzonitrile reduction, electrocatalysis, copper-based electrodes,
copper−silver-based electrodes

The text can also be downloaded from publisher:https://pubs.acs.org/doi/10.1021/acssuschemeng.5c02168