Kinetics of Ce(IV) oxidation of α-keto acids in sulfuric-perchloric acid media

The rates of oxidation of four α-keto acids, glyoxylic, pyruvic, phenylglyoxylic, and 2-oxobutyric acids by Cerium(IV) in H₂SO₄HaHSO₄ and H₂SO₄HClO₄ solutions, have been studied spectrophotometrically. The rate data suggest that CeSO is the most reactive of the Cerium(IV)-sulfate complexes present in the H₂SO₄NaHSO₄ and H₂SO₄HClO₄ systems. The oxidation reaction is proposed to be a one-electron process with the rate-determining step being the decomposition of a α-ketoacid-Cerium(IV) complex to a free radical and carbon dioxide through a transition state.