Acid–base equilibria of substituted benzoic acids. Part I

Abstract

A spectrophotometric determination of the dissociation constants of benzoic acid and its alkyl derivatives has been made. A computer programme has been written to enable the thermodynamic quantities ΔG°, ΔH, and ΔS° to be calculated at a number of selected reference temperatures within a temperature range. The thermodynamic quantities for benzoic acid and some of its alkyl derivatives have been calculated from the dissociation constants obtained in this investigation at temperatures within the range 15–40°C; the corresponding quantities for halogeno-, nitro-, cyano-, and hydroxy-derivatives have been calculated from literature values. The relative strengths of these acids are discussed.