Kinetics and mechanism of oxidation of lactic acid by dihydroxyditelluratoargentate (III) in alkaline medium

The kinetics of the oxidation of lactic acid (Lac) by dihydroxyditelluratoargentate (III)[abbreviated as DDA of Ag(III)] anions was studied in an aqueous alkaline medium by conventional spectrophotometry in a temperature range of 25-40 degreesC. The order of the redox reaction of lactic acid and DDA was found to be first-order. The rates increased with the increase in [OH-] and decreased with the increase in [tellurate]. No free radical was detected. In the view of this the dihydroxymonotelluratoargentate(III) species(DMA) is assumed to be the active species. A plausible mechanism involving a two-electron transfer is proposed, and the rate equation derived from the mechanism can be used to explain all the experimental results. The activation parameters(25 degreesC) and the rate constants of the rate-determining step along with the preequilibrium constants at different temperatures were evaluated.