Electrosynthesis of nitriles from primary alcohols and ammonia on Ni catalyst

Despite the increasing interest on electrocatalytic refinery of renewable feedstocks to produce value-added chemicals, nitrile electrosynthesis from alcohols is rarely studied. Here, we report the direct electrosynthesis of nitriles from primary alcohols and ammonia, with a simple nickel catalyst under benign conditions in aqueous electrolytes. The highest benzonitrile faradaic efficiency of 63.0% was achieved at 1.375 V vs. RHE. The reaction proceeds via a dehydrogenation-imination-dehydrogenation sequence, with the rate-determining step likely involving the cleavage of α-carbon C-H bond of the alcohol. Based on the electrochemical and in-situ Raman analyses, we propose that the in-situ formed Ni2+/Ni3+ redox species serves as the active site for converting alcohol to nitrile, while Ni2+ also exhibits capability for the oxidation of imine. Various aromatic, aliphatic and heterocyclic primary alcohols were transformed to the corresponding nitriles, exhibiting broad feasibility. This study offers a promising electrocatalytic system for the sustainable synthesis of high-value nitriles.