Reactivity of nucleophiles towards X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides: Kinetics, activation volumes and mechanism

The kinetics of the reaction of four X-3-(p-tolylsulfonyl)-1,2,3-benzoxathiazole 2,2-dioxides (X=S-Cl, 5-Br, 5-NO₂ and 6-NO₂) with hydroxide ion and imidazole in aqueous acetonitrile and aqueous ethanol solutions were investigated at various pressures. The volumes of activation were all found to be negative and consistent with a bimolecular reaction involving considerable solvent electrostriction. No significant dependence on the solvent composition was found.