Formation of glyoxylic acid by oxidative dehydrogenation of glycolic acid

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 degrees 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%.