CATALYTIC-OXIDATION WITH AIR OF TARTRONIC ACID TO MESOXALIC ACID ON BISMUTH-PROMOTED PLATINUM

Mesoxalic acid (ketomalonic acid) was prepared by oxidative dehydrogen ation with air of tartronic acid in aqueous solution on carbon-support ed platinum-bismuth catalysts. By increasing the pH, using a higher ca talyst/substrate ratio or increasing the temperature, higher yields co uld be obtained (maximum yield obtained of 65% at 80% conversion). The results obtained for this reaction and for the analogous catalytic ox idations of glyceric acid to hydroxypyruvic acid, and lactic acid to p yruvic acid, enabled a general reaction mechanism to be proposed for t he selective oxidation of alpha-hydroxy acids to alpha-keto acids on p latinum-bismuth catalysts.