Formation of Glyoxylic Acid by Oxidative Dehydrogenation of Glycolic Acid

Abstract Iron phosphates with a P/Fe atomic ratio of 1.2 were found to be effective as catalysts for a vapor-phase oxidative dehydrogenation of glycolic acid to glyoxylic acid. The effects of the reaction variables on the conversion and selectivity were studied. The optimum reaction temperature was around 240 °C and the optimum feed rate of oxygen was in the range of 10 to 25 mmol h−1 when the feed rate of glycolic acid was 12.3 mmol h−1. The reaction was not affected by a variation in the feed rate of water vapor in the range of 86 to 480 mmol h−1. The selectivity to glyoxylic acid remained unchanged at 74 mol% with an increase in the conversion of glycolic acid up to 70%; the highest yield of glyoxylic acid was 56.5 mol% at the conversion of 80%.