Article révisé par les pairs
Résumé : The effects of water and alcohols on values of ΔG+ + for the solvolysis of t-butyl chloride have been correlated with various solvent parameters. It is shown, however, that neither simple nor multiple correlations yield information about the nature of the solvolysis because in these solvents the parameters are usually collinear. Transfer free energies of the transition state, ΔGt°(Tr), have been correlated with ΔGt° values for α-amino-acids and the Me4N+Cl- ion-pair. For transfers to water, these correlations are improved by correction for the size or cavity effect, using scaled particle theory, the Sinanoglu-Reisse-Moura Ramos method, or the division into neutral and electrostatic contributions. Plots of the corrected ΔGt° values, corresponding to the solute-solvent interaction terms, for the transition state against the α-amino-acids and the ion-pair show that the transition state is very polar, though not so polar as the ion-pair, and that α-amino-acids are excellent models for the solvolysis transition state.