POLARITY AND HYDROGEN-BONDING ABILITY OF SOME BINARY AQUEOUS ORGANIC MIXTURES

The solvatochromic parameters pi* for the polarity/polarizability, beta for the hydrogen-bond accepting (electron-pair-donating) ability, and alpha for the hydrogen-bond-donating ability of binary aqueous tetrahydrofuran, N,N-dimethylformamide, pyridine, dimethyl sulphoxide, formamide and formic acid have been determined spectro-photometrically at 25-degrees-C as functions of the composition of the mixtures. They were compared with the local composition of the environment of each kind of molecules in the mixtures, obtained from theoretical models. These parameters were also determined for several water-saturated alkanols and tri-n-butyl phosphate, that are of significance in liquid-liquid distribution studies of organic solutes.