Oxidative decarboxycondensation of pyruvic acid to citraconic anhydride

Article abstract of DOI:10.1246/cl.1996.247

Citraconic anhydride (Methyl maleic anhydride) was found to be produced from pyruvic acid by an oxidative decarboxy-condensation. The presence of oxygen is required to promote the reaction. The best catalyst is iron phosphate with a P/Fe atomic ratio of 1.2 and the optimum temperature is about 200 °C. The one-pass yield reaches 71 mol% at a pyruvic acid conversion of 98%. The main side-reaction is the formation of acetic acid and CO₂ by oxidative C-C bond fission.