Base-Catalyzed Oxidation of Aminotriazole Derivative by Permanganate Ion in Aqueous Alkaline Medium: A Kinetic Study

Abstract

Kinetic investigation on the oxidation of one of the aminotriazole derivatives, namely N,N-dimethyl-N'-(4H-1,2,4-triazol-3-yl) formamidine (ATF) by permanganate ion in alkaline medium has been performed at a constant ionic strength of 0.1 mol dm -3 and at 25 o C. The progress of the reaction was followed spectrophotometrically. Both spectroscopic and kinetic evidences reveal formation of a 1:1 intermediate complex between the oxidant and substrate. The influence of pH on the oxidation rate indicated that the reaction is base-catalyzed. The reaction shows first order dependence with respect to , and fractional-first order dependences on both [ATF] and [OH -]. Increasing ionic strength and dielectric constant did not affect the reaction rate. Addition of small amounts of alkali-metal ion catalysts was found to accelerate the oxidation rate and the order of effectiveness of the ions was: Li + > Na + > K + . The final oxidation products of ATF were identified as 3-aminotriazole, dimethyl amine and carbon dioxide. A plausible reaction mechanism consistent with the kinetic observations is proposed, and the reaction constants involved in the different steps of the mechanism have been evaluated. The activation parameters with respect to the slow step of the reaction, along with thermodynamic quantities of the equilibrium constants are calculated and discussed.