Study of the proton transfer processes of nitrophenols to nitrobenzoic acids and to benzoic acid in water-dimethylsulfoxide mixtures compared with the same process in the gaseous phase.

A study of the proton transfer processes from the nitrophenols to nitrobenzoic acids in water-DMSO mixtures compared with the processes in the gaseous phase is presented. By means of two thermodynamic cycles which refer to a gaseous initial thermodynamic state, it has been possible to calculate the "external" interactions of the cited processes. The internal hydrogen bond plays a very important role, in the gas and in the liquid phase, for the ortho isomers. In the para derivatives the resonance effect prevails in the solvation of the phenols over the whole morel fraction, while in the meta derivatives the inductive effect influences the solvation of the phenols only in water-rich solutions.