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

A study of the proton transfer of the nitro-substituted benzoic acids in water-dimethylsulfoxide mixtures compared with the same process in the gaseous phase.

A study of the proton transfer process from nitro-substituted benzoic acids to benzoic acid in H2O-DMSO mixtures compared with the same process in the gaseous phase is presented. A thermodynamic cycle allows calculation of a transfer process in solvent X which refers to a gaseous initial state, i.e. dDPi g->x. These thermodynamic quantities have been assumed as a measure of "external" solute-solvent interactions. It may be noted that in solution the resonance effect appears in the ortho-anion, while in the gaseous phase the resonance is effective for the para-compound. A comparison with the chloroisomers shows that the proton transfer process is easier for the nitro-isomers in the gas phase while the contrary is true in solution

Termodinamica dei dipeptidi. Influenza delle forze idrofobiche delle catene laterali sui processi di dissociazione di alcune serie di dipeptidi.

Trento, 10 - 11 settembre 2001