Kinetics of neutral hydrolysis of 1-benzoyl-3-phenyl-1,2,4-triazole in highly aqueous media: analysis of effects of added ethanol and propan-1-ol in terms of pairwise group interaction parameters

Abstract

Over the range 288.15 ≤T/K ≤ 333.15, the first-order rate constant for the neutral hydrolysis of 1-benzoyl-3-phenyl-1,2,4-triazole in aqueous solutions (pH ca. 4) decreases when either ethanol or propan-1-ol is added. The kinetic data are analysed in terms of (a) the dependence of rate constant on temperature at fixed molality of added alcohol, and (b) the dependence of rate constant on molality of added alcohol at fixed temperature. In the latter case, the analysis leads to Gibbs energy interaction parameters which are assigned to group interaction parameters G(CH) and G(OH) for methine and hydroxy groups respectively. G(CH) is negative and G(OH) is positive, the corresponding enthalpic pairwise group interaction parameters having the opposite sign. This pattern is consistent with a more dramatic effect of added alcohol on the initial than on the transition state for the water-catalysed hydrolysis of the activated amide.