Oxidation of 4-Methylthio phenyl acetic acid in aqueous acidic medium by Cr (VI): Kinetic and Mechanistic Study

The kinetics and oxidation of 4-methylthiophenyl acetic acid by acidified potassium dichromate was studied spectro photometrically at constant ionic strength 0.01 mol/dm3. The reaction exhibits 2: 1 stoichiometry. The first order dependence of the reaction on [K2Cr2O7]o was noticed and less than unity order dependence on [MTPA] o and [H2SO4]. The reaction was studied by varying the temperature and the activation parameters are calculated from the experimental data. The activation parameters Ea(kJ/mol), Delta H#(kJ/mol), Delta S#(J/K/mol) and Delta G#(kJ/mol) for the rate determining step were obtained. Impact of ionic strength has been studied. Rate constant for the rate determining step was calculated and a suitable mechanism has been proposed. (C) 2018 Elsevier Ltd. All rights reserved. Selection and Peer-review under responsibility of International Conference on Advanced Materials and Applications (ICAMA 2016).