Electrosynthesis of Glyoxylic Acid in a Cooled Cathode Reactor

Glyoxylic acid was produced by electroreduction of oxalic acid in a well designed cooled cathode reactor. The cathodic and anodic electrolytes were super-saturated oxalic acid and hydrochloric acid aqueous solutions separated by a super-acid ion-exchange membrane. The current efficiency and time-space yield of glyoxylic acid were studied under different temperatures of cathode and electrolyte, current densities, materials of cathode. With the cooled cathode reactor, the energy consumption was reduced and higher oxalic acid concentration was available in solution, so that current efficiency was improved. The results indicated that the average time-space yield of glyoxylic acid was about 0.032 kg·dm-3·h-1 and the concentration of glyoxylic acid could reach 3.52 % after 3.7 h electrolysis with cathode of lead and anode of graphite board under conditions of temperature 20 ℃, catholyte flow rate of 1.08 m·s-1 and current density of 409.46 A·m-2 in the cooled cathode reactor.