Kinetics of dimethylsulfoxide oxidation by chlorine dioxide

The kinetics and mechanism of reaction between chlorine dioxide and dimethyl sulfoxide were studied in the tetrachloromethane solution. Time-dependent changes of ClO2 concentration were obtained with ESR method by measurement of integral intensities of ESR signals. It was shown that the thermal decomposition of chlorine dioxide and its reaction with DMSO take place simultaneously with comparable rates. At low concentrations ClO2 decomposes by the monomolecular mechanism, but the bimolecular decomposition becomes predominant as the concentration is increased. The rate constants of the thermal decomposition of ClO2 (1,4∙10-5 c-1, 28 ºC) and the interaction with DMSO were determined at low concentrations of ClO2 (0,6∙10-5 c-1, 28 ºC). Probable mechanism of interaction between ClO2 and DMSO was proposed.