Production of tartrate and glycolate from the electrochemical reduction of glyoxylate

Abstract

There has been considerable controversy about these reductions. Bewick and Greener [7, 8] claimed to have produced glycolic acid from CO2 on lead and malic acid from CO2 on mercury but they did not detect glyoxylic acid. Similar results were reported by Wolf and Rollin [9] but others were unable to repeat these results, or obtained different products [3]. A number of workers have studied the voltammetric reduction of glyoxylic acid [10, 11]. But there have been no direct preparative studies since Bauer [12] in 1931. Some preparative studies are presented here. It has been generally assumed that the electrochemical reduction of glyoxylate goes by a two electron process to give glycolate (perhaps explaining Bewick's results [7]). However another possibility exists: the formation of tartaric acid by a one-electron reduction followed by a dimerisation (pinacol formation). Further reduction of tartaric acid could lead to malic acid (as claimed by Bewick [8] and Wolf [9]). We observed an HPLC peak from the reduction products of the reduction of oxalic acid which could be attributable to malic acid [4].