Electrochemical oxidation of ethylene glycol in a channel flow reactor

Electrochemical oxidation of ethylene glycol has been studied in a channel flow reactor (CFR) on high surface area platinum at three different flow rates and varying potentials. Sampled current potential obtained from chronoamperometry experiments agrees well with the voltammetry data reported in the literature. The current at any potential was observed to be a weak function of the flow rate. The products of the oxidation reaction have been identified using high performance liquid chromatography (HPLC). In addition to all the usual C2 fractions (glycolaldehyde, glycolic acid, glyoxylic acid, glyoxal and oxalic acid) already reported, an important C1 fraction (formic acid) has been observed in significant quantities at low flow rates. The results of this study suggest cleavage of C-C bond, though the exact pathway remains unclear. Further, distinct changes in the product profile (amount of different C1 and C2 fractions) were observed with flow rate. Glycolic acid was the only product that was observed in significant quantities at all flow rates. The results suggest interplay of contact time of the reactants with the thin film catalyst, kinetics and reaction pathway and demonstrate the usefulness of a channel flow reactor.