Kinetics and salt effects on the alkaline hydrolysis of perbenzoate ion

Abstract

The rates of hydrolysis of perbenzoate ion in alkaline aqueous solutions have been studied over a wide range of concentrations of the reactants at different temperatures. The rate equation is (i) where k₁=(4·8 ± 0·8)× 10^–6 s^–1, –d[PhCO₃^–]/dt ={k₁+k₂[OH^–]+k₃[OH^–]²}[PhCO₃^–](i)k₂=(3·32 ± 0·04)× 10^–4 l mol^–1 s^–1, and k₃=(6·1 ± 0·2)× 10^–4 l² mol^–2 s^–1 at 25 °C and at ionic strength 0·5M(NaClO₄). The activation parameters have been measured, and the mechanism of the reaction is discussed. Added salts exert a positive effect on the rates of the reaction, except tetraethylammonium perchlorate. The rateenhancing effect lies in the order Co(NH₃)₆³⁺ Sr²⁺ < Ba²⁺ K⁺≃ Na⁺ < N⁺. The salt effect is discussed on the basis of the incorporation of added cations into the transition state.