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Chemical Research in Chinese Universities ›› 2003, Vol. 19 ›› Issue (2): 219-221.

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Kinetics and Mechanism of Oxidation of Lactic Acid by Dihydroxyditelluratoargentate(Ⅲ) in Alkaline Medium

SHAN Jin-huan, WANG Li, LIU Bao-sheng, SHEN Shi-gang, SUN Han-wen, WANG An-zhou   

  1. College of Chemistry and Environment Science, Hebei University, Baoding 071002, P. R. China
  • Received:2001-07-21 Online:2003-04-24 Published:2011-08-06
  • Supported by:

    Supported by the National Natural Science Foundation of Hebei Province(No.295066).

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Abstract: 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 ℃. 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 ℃) and the rate constants of the rate-determining step along with the preequilibrium constants at different temperatures were evaluated.

Key words: Dihydroxyditelluratoargentate(Ⅲ), Lactic acid, Kinetics and mechanism, Redox reaction