Equilibria and kinetics in the isomerisation of o-formylbenzoic acid

Abstract

The pK value of o-formylbenzoic acid measured by conventional means has been compared with the value derived from observations of the catalytic effect of its anion in the decomposition of nitramide and the mutarotation of glucose. It is concluded that in aqueous solution at 25 °C 93·7% of the acid exists as its cyclic isomer. Measurements of pK values in the temperature range 20–60°C were used to determine the enthalpy of ionization (ΔH= 5·9 kJ mol–1). The temperature-jump relaxation method has been used to study the kinetics and mechanism of the isomerisation.