Electrosynthesis of glycine from bio-derivable oxalic acid

Abstract: Electrochemical hydrogenation of non-fossil resources to produce value added chemicals has great potential to contribute to realization of sustainable material supply. We previously demonstrated that TiO₂ catalyzed electrochemical reduction of biomass-derivable α-keto acid in the presence of NH₃ or NH₂OH affords amino acids. In this work, we focused on oxalic acid, which is producible by chemical degradation of agro wastes, as a starting material for the electrosynthesis of an amino acid. We examined the electrocatalytic properties of various materials, including Cu, Pt, Ti foils, calcined Al, Co, Mo, Nb, Ni, Ti, V, W, Zr foils, and some TiO₂ catalysts, by conducting linear sweep voltammetry (LSV) measurements, and found that Mo and Ti foil calcined at 450 °C show favorable catalytic features for the one-step glycine electrosynthesis from oxalic acid and NH₂OH. Electrochemical reduction of oxalic acid at an applied potential of − 0.7 V using calcined Ti foil resulted in formation of glycine and glyoxylic acid oxime, i.e., intermediate of the glycine formation, with moderate Faradaic efficiency of 28 and 28%, respectively. Graphic abstract: [Figure not available: see fulltext.]