高等学校化学研究 ›› 2003, Vol. 19 ›› Issue (2): 219-221.
SHAN Jin-huan, WANG Li, LIU Bao-sheng, SHEN Shi-gang, SUN Han-wen, WANG An-zhou
SHAN Jin-huan, WANG Li, LIU Bao-sheng, SHEN Shi-gang, SUN Han-wen, WANG An-zhou
摘要: 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.