Kinetic and mechanistic study of oxidation of phenyl thiourea by pyridinium chlorochromate in aqueous DMF medium

Oxidation of Phenyl Thiourea by pyridinium chlorochromate in aqueous DMF medium, containing perchloric acid has been studied. The rate of reaction was found to be of first order with respect to [PCC], [PTU] and [H+]. The increase in the rate of oxidation with increase in acidity indicates the involvement of a protonated chromium(VI) species in the rate-determining step. the rate of reaction increased with increase in dielectric constant of the reaction medium., which indicates that there is involvement of an ion–dipole type of interaction in the rate-determining step. The activation parameters have been evaluated. On the basis of the experimental findings, a suitable mechanism and rate law has been proposed.