Abstract

The kinetic investigation of oxidation of thiourea by quinolinium dichromate (QDC) in perchloric acid medium at constant ionic strength was studied spectrophotometrically at 440 nm. A stoichiometric ratio of 3:1 with thiourea versus QDC was observed. The reaction was first order with respect to thiourea, monomeric QDC (QMC) and HClO₄. Induced polymerization of acrylonitrile was observed. The mechanism involved the attack of protonated monomeric QDC (QMC) on the substrate in the rate determining step forming the products. Addition of Mn(II) has no effect on the reaction rate. The effect of anionic micelle (SDS) and neutral micelle (TX-100) on the system was studied using Berezin’s kinetic model and observed a partial inhibitory effect on the rate of the reaction. The thermodynamic parameters like ΔE_a ΔS and ΔG have been calculated and possible mechanism was proposed.

Keywords

Monomeric quinolinium dichromate, QMC, Oxidation, Effect of anionic and neutral (TX-100) micelle