The Research On The Cathodic Material And Paired Reaction For The Electropreparation Of Glyoxylic Acid From Oxalic Acid

Glyoxylic acid has played an important role in the field of biological chemistry and organic synthesis. Preparing glyoxylic acid by electro-reduction of oxalic acid is worthy of being studied for such advantages as available raw materials, few outgrowth, without pollution, easy purification of the outcome, relatively low cost, etc.Studies on electro-reducing oxalic acid into glyoxylic acid showed the reaction is feasible on proper cathodes and a few tetrabutylammonium bromide and lead ion in cathodic solution can prevent the cathode from losing activity. Proper electrolytic conditions were obtained and the final concentration of glyoxylic acid reached 16g/L.Different kinds of electrodes were prepared by electrochemical deposition and polymerization, and then the electrochemical behaviors of those were investigated. The results demonstrated that tiny powder such as TiO2 exhibited a high activity to the reaction of electro-reducing oxalic acid into glyoxylic acid and Pb/C-POT-TiO2 electrode, which can substitute traditional lead cathode for the merit of low cost and high electro-activity, is better cathodic material according to the stability and electrochemical activity in the oxalic acid solution. The SEM test of Pb/C-POT-TiO2 electrode showed that even polymer film formed on the fundus and EDS test showed Ti existed in the film as the form of TiO2. Good results were achieved in the amplificatory experiments applying Pb/C-POT-TiO2 cathode for the electro-reduction of oxalic acid.Proper electrolytic conditions of the electro-oxidation of glucose in separate electrobath were confirmed through experiments. The paired electrolytic experiments of oxalic acid and glucose were carried out according to the following conditions: Pb/C-POT-TiO2 cathode; Ti/PbO2 anode; Cathodic,solution was saturated oxalic acid and anodic solution was the mixture of 0.8mol/L glucose and 0.4mol/L KBr; HF-101 ion exchange membrane; 20 C; Current density was 300A/m2 ; Electrolysis lasted four hours; Oxalic acid was added into cathodic solution and NaOH was added into anodic solution constantly during the electrolysis process. 20g/L glyoxylic acid in cathodic solution and 0.55mol/L sodium gluconate in anodic solution were obtained,whichproved that the paired electrolysis of oxalic acid and glucose is feasible.