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Oxidation of Some Unsaturated Acids by Tetraethylammonium Chlorochromate : A Kinetic and Mechanistic Study

S. Barthora, A. K. Meena, M. Gehlot, P. T. S. R. K. Prasad Rao and Vinita Sharma

The oxidation of maleic, fumaric, crotonic and cinnamic acids by tetraethylammonium chlorochromate (TEACC) in dimethylsulphoxide (DMSO) leads to the formation of corresponding epoxide. The reaction is of first order with respect to TEACC and the acid. Due to non-aqueous nature of the solvents, toluene-p-sulphonic acid (TsOH) was used as the source of hydrogen ions. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation of these acids was studied in nineteen different organic solvents. The solvent effect was analyzed by Kamlet’s and Swain’s multiparametric equations. Solvent effect indicated the importance of the cationsolvating power of the solvent. A mechanism involving a three-centre transition state has been postulated.