SOLVATION POTENTIALS AND TRANSPORT-PROPERTIES IN 1,4-DIOXANE PLUS WATER MIXTURES

Emf measurements at 298 K are reported for galvanic cells with flowing liquid junctions in which one half-cell contains an aqueous electroly te solution and the other contains the same electrolyte in 1,4-dioxane + water mixtures of varying composition. The electrolytes HCl, NaCl, KCl and CsCl were studied in the dioxane + water system using silver\s ilver chloride electrodes in each half-cell in solutions ranging from pure water up to 0.2 mole fraction dioxane (55 wt%). The data were com bined with standard Gibbs energies of transfer and conductance data fr om the literature to obtain solvation potentials and transport numbers for the electrolytes, from which useful thermodynamic data may be ext racted. The solvation characteristics of the dioxane + water system ar e discussed and compared with those in methanol + water and DMF + wate r solvent systems. It is apparent that cation solvation by the organic component is more significant in dioxane + water than in DMF + water, particularly at low mole fractions.