Kinetics and Mechanism of Oxidation of 3-phenoxy-1,2-propanediol by Ditelluratocuprate(III) in Alkaline Medium

Jinhuan Shan,Haixia Shen,Jiying Zhang,Yanping Liu,Yafeng Yang

doi:10.5539/ijc.v3n2p111

Abstract

The kinetics of oxidation of 3-phenoxy-1,2-propanediol by ditelluratocuprate(III) (DTC) in alkaline liquids has been studied spectrophotometrically in the temperature range of 293.2 K-313.2 K. The reaction rate showed first order dependence in DTC and fractional order with respect to 3-phenoxy-1,2-propanediol. It was found that the pseudo-first order rate constant k obs increased with an increase in concentration of OH - and a decrease in concentration of TeO 4 2- . The reaction rate changed with the position of hydroxyl group. There is a negative salt effect. A plausible mechanism involving a pre-equilibrium of a adduct formation between the complex and 3-phenoxy-1,2-propanediol was proposed. The rate equations derived from mechanism can explain all experimental observations. The activation parameters along with the rate constants of the rate-determining step were calculated.

Highlights

Materials and apparatusAll the reagents used were of A.R. grade
Based on the studies of oxidation of some organic compounds by Cu(III) complex, Indian researchers proposed that in the alkaline medium the formula of DTC may be represented by [Cu(H4TeO6)2]- and the mechanism involving a pre-equilibrium of a adduct formation between the complex and reductant was proposed
The kinetic measurements were performed on a UV-vis spectrophotometer (TU-1900, Beijing Puxi Inc., China), which had a cell holder kept at constant temperature (± 0.1 oC) by circulating water from a thermostat (DC-2010, Baoding, China)

Summary

Materials and apparatus

All the reagents used were of A.R. grade. All solutions were prepared with doubly distilled water. Solutions of [Cu(H4TeO6)2]- (DTC) and 3-phenoxy-1,2-propanediol were always freshly prepared before using. L. 1968, Jaiswal, P. Its electronic spectrum was found to be consistent with that reported by Jaiswal and Yadava

Kinetics measurements

Product analysis

Evaluation of Pseudo-First Order Rate Constants

Reaction Mechanism

Conclusion