Electrochemical Synthesis of Glycine from Oxalic Acid and Nitrate.

In manufacturing C-N bond-containing compounds, it is important challenge to alternate the conventional methodologies that utilize reactive substrates, toxic reagents and organic solvents. In this study, we developed an electrochemical method to synthesize a C-N bond-containing molecule avoiding the use of cyanides and amines by harnessing nitrate (NO 3 - ) as a nitrogen source in an aqueous electrolyte. In addition, we utilized oxalic acid as a carbon source which can be obtained from electrochemical conversion of CO 2 , so that our approach can provide a route for the utilization of anthropogenic CO 2 and nitrate wastes which cause serious environmental problems including global warming and eutrophication. Interestingly, the coreduction of oxalic acid and nitrate generated reactive intermediates, which led to C-N bond formation followed by further reduction to an amino acid, namely, glycine. By carefully controlling this multireduction process with a fabricated Cu-Hg electrode, we demonstrated the efficient production of glycine with a faradaic efficiency (F.E.) of up to 43.1% at -1.4 V vs. Ag/AgCl (current density = ~90 mA cm -2 ).