Carbon dioxide production in the oxidation of organic acids by Cerium(IV) under aerobic and anaerobic conditions

Abstract

The stoichiometry of CO2 production during the ceric oxidation of various organic acids is measured under conditions with organic acid excess. Measurements utilize a photo- metric methodology. For anaerobic conditions stoichiometries (CO2)produced : (Ce(IV))reduced of about 0 (malonic acid), 0.5 (e.g., glyoxylic acid), and 1.0 (oxalic acid) are found. Oxalic acid showed an oxygen-induced decrease of CO2 production, while other compounds such as ma- lonic acid increased the amount of produced CO2 or showed no changes (e.g., tartronic acid). In the case of mesoxalic acid the stoichiometry is increased from about 0.5 to 2.0 due to the presence of molecular oxygen. The results are discussed on the basis of simple reaction mech- anisms demonstrating that useful information on reaction pathways and intermediates can be extracted from these simple measurements. q 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 899- 902, 1998