Oxidation of some dicarboxylic acids by aqueous coblatic perchlorate

Abstract

The kinetics of oxidation of succinic, aspartic, maleic and fumaric acid and their sodium salts by trivalent cobalt in aqueous perchloric acid medium was studied in the temperature ranges 15 to 30˚C. The reaction were found to be first order with references to [ Co3+] and [substrate] and no evidence for MICHALIS-MENTEN kinetics was noticed except for succinic acid at high concentration. With all the acids an inverse dependence of the rates on [H+] was observed. Conclusion were drawn as to the nature of the active species of Co3+ from the Offer of acidity viz CoOH2+ was the active species in the case of malic, fumaric and aspartic acid while both Co3+ and CoOH2+ were the active active entities with succinic acid. The effect of initial addition of [Co2+], ionic strength and temperature was also studied. The kinetics of the oxidation of the sodium salts of these acids were restudied on the same lines. For purpose of camparison. Some interesting results were noticed with maleic and fumaric acids and their sodium salts. Probable reaction mechanisms were suggested . Rate constants, activation energy and entropy values were computed from experimental results and discussed.