Initial state and transition state contributions to reactivities for hydrolysis of trimethylamine sulphur trioxide in aqueous salt solutions

Solubilities and enthalpies of solution are reported for trimethylamine sulphur trioxide, Me₃NSO₃, dissolving in water and in aqueous potassium bromide and aqueous tetra-n-butylammonium bromide solutions. From these solubility data and published kinetic data, reactivity trends for hydrolysis of Me₃NSO₃ in aqueous salt solutions are analysed into initial state and transition state components. Setchenow coefficients are derived, both for Me₃NSO₃ itself and for its hydrolysis transition state. In both cases, the small changes in rate constant when salt is added stem from more marked effects of the salt on the initial and transition states.