HYDROGEN-BONDING SOLUTIONS .1. PARTIAL MOLAR VOLUMES AND OPTICAL SUSCEPTIBILITIES FOR WATER, METHANOL, AND ETHANOL IN 1,4-DIOXANE

Power series or rational polynomials have been fitted to the available density and refractive index data for the three binary solutions over the full composition range at 25-degrees-C. Excess molar volumes V(E) and optical susceptibilities Y(E) were evaluated from the fits and were used to evaluate partial molar properties V(i)E and Y(i)E, where i is 1 for the polar component and 2 for dioxane. The values were generally small and negative, although both V2E and Y2E were sharply negative for dilute dioxane in all three solutions. The Y(E) values appear to be slightly negative at high dilution, but better data are needed to confirm this. The optical susceptibility results were in qualitative agreement with predictions based on the Onsager-Bottcher model theory, and component contributions to the Y(i)E evaluated from the model theory were found to be large but opposite in sip and nearly canceling. This type of behavior is expected when one component (dioxane) is considerably more polarizable than the other. The available data are not sufficiently precise to resolve the effect of hydrogen bonding on the polarizabilities. The use of thermodynamic methods on molar susceptibilities, as illustrated in this paper, is recommended to both experimentalists and theorists. Analysis of dielectric data is carried out in a companion paper.