Abstract
Kinetics of the initial stages of oxidation of tartaric acid (TA) in the absence and presence of manganese(II) ions have been studied spectrophotometrically. The rate of the induction was slow and then gradually increased with increasing [TA] and/or [HClO^sub 4^]. The reaction followed third-order kinetics; first-order with respect to each of [TA], [HClO^sub 4^] and [Cr^sup VI^]. The kinetic and manganese(II) effect studies are consistent with a one-step three-electron mechanism (Cr^sup VI^ [arrow right] Cr^sup III^ without passing through Cr^sup IV^ as an intermediate) in which a termolecular complex is formed between TA, Mn^sup II^ and HCrO^sub 4^^sup -^. In order to obtain further insight, oxidation of glyoxylic acid (GA), an oxidation product of TA, was also studied under the similar conditions. Details of the process are discussed.[PUBLICATION ABSTRACT]