Kinetics and Mechanism of Oxidation of 1,2-Butanediol by Argentate(III) Complex in Alkaline Medium
S.-Y. Huo*, J.-H. Shan, S.-G. Shen and H.-W. Sun
College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
(Received 20 March 2006, Accepted 12 April 2006)
The kinetics of oxidation of 1,2-butanediol by dihydroxyditellutoargentate(III) (DDA) is studied spectrophotometrically. The reaction rate shows first order dependence in DDA and 1 < nap < 2 order in 1,2-butanediol. It is found that the pseudo-first order rate constant kobs increases with the increase in concentration of OH- and decreases with the increase in concentration of TeO42-. There is a negative salt effect; no free radical is detected. In view of this, the dihydroxymonotelluratoargentate(III) species is assumed to be the active species. A plausible mechanism involving a two-electron transfer is proposed and the rate equations derived from mechanism explains all experimental results. The activation parameters along with the rate constants of the rate-determining step are calculated.
Keywords: Dihydroxyditellutoargentate(III), 1,2-Butanediol, Redox reaction, Kinetics and mechanism