Ion-pair return in the solvolysis of the unstable carbocation system

Abstract

The behavior of carbocation having electron withdrawing CF₃ group at reaction center is interesting as unstable carbocation system. We were determined the rate constants for the solvolysis (k_solv), the reaction of carbocation with solvents (k_s), and the isomerization from alkoxy-¹⁶O tosylate to alkoxy-¹⁸O tosylate (k_iso) in the solvolysis of 1-(3,5-dimethylphenyl)-2,2,2-trifluoroethyl tosylate in 50/50 (v/v) TFE/Water (I = 0.5, NaClO₄) at 25^oC. The rate constant for the return from this unstable ion pair (k_-1) is estimated based on these rate constans. We will discuss the behavior of ion pair intermediate generated in this solvolsysis based on these rate constants