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 electrolyte 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\silver chloride electrodes in each half-cell in solutions ranging from pure water up to 0.2 mole fraction dioxane (55 wt%). The data were combined with standard Gibbs energies of transfer and conductance data from the literature to obtain solvation potentials and transport numbers for the electrolytes, from which useful thermodynamic data may be extracted. The solvation characteristics of the dioxane + water system are discussed and compared with those in methanol + water and DMF + water 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.