The Pseudo Thermodynamics of Solvolysis. A Detailed Study of the Pressure and Temperature Dependence of Benzyl Chloride Solvolysis in t-Butyl Alcohol – Water Mixtures

Abstract

The pseudo first order rate constants for the solvolysis of benzyl chloride in aqueous t-butyl alcohol (t-BuOH) are reported at 40.00, 50.25, and 60.50 °C at various pressures up to 4084 atm. From these data the first temperature derivatives (ΔH* and ΔS*), the first (ΔV*) and second pressure derivatives, ∂ΔV*/∂P, and the mixed second derivative, ∂ΔV0*/∂T, of the rate are evaluated. These activation parameters exhibit extremum behavior in the highly aqueous solvent region. This behavior is discussed in terms of solvent structure variation. The signs of the pressure dependence of ΔH* and ΔS* are shown to be consistent with those required by the Maxwell type relationships for classical thermodynamic systems.