KINETICS, KINETIC ISOTOPE EFFECTS, AND SUBSTRATE SELECTIVITY OF ALKYLBENZENE OXIDATION IN AQUEOUS PERMANGANATE SOLUTIONS .4. THE ACTIVATIONPARAMETERS FOR REACTIONS WITH THE MNO4- ANION

The kinetic distribution method is used to obtain the gas/solution par tition coefficients and to investigate the kinetics of the first slow stage of the oxidation of toluene, o-, m-, and p-xylenes, mesitylene, pseudocumene, and ethyl- and isopropylbenzenes in the KMnO4-H2O system at 20-70 degrees C and pH = 5-7 when the MnO4- anion acts as a reagen t. The reaction is first-order with respect to both the substrate and MnO4-. The correlation between the activation energy and the C-H bond homolytic dissociation energy and the compensation dependence between Delta H double dagger and Delta S double dagger are revealed. These de pendences are found to be common for alkylarenes and cycloalkanes. The data obtained supports the assumption that the oxidation of alkylbenz enes and alkanes by the MnO4- anion begins with a slow stage of alkyl C-H bond rupture.