Studies of Solvolyses of 1,4-Benzodioxan-6-Sulfonyl Chloride by Extended Grunwald-Winstein Equation

摘要

The rate constants of solvolysis of 1,4-benzodioxan-6-sulfonyl chloride (C8H7ClO4Cl, 1) were determined by a conductivity technique. These rate constants of 1 in 28 different solvents correlated well with the extended Grunwald-Winstein equation. The l (1.00) andm(0.59) values support an S(N)2 reaction pathway having a similar transition state structure to that of the benzenesulfonyl chloride (2, l = 1.10, m = 0.61) reaction. This interpretation is further supported by the activation parameters, i.e., relatively small positive Delta H-not equal (8.9 to 15.5 kcal/mol) and large negative Delta S-not equal (-27.3 to -49.2 cal/mol/K) values, and the solvent kinetic isotope effect (1.62). The Kivinen's n values (n = 0.03 in methanol, 0.04 in ethanol) obtained in binary solvents were consistent with the proposed bimolecular reaction mechanism.