Excess Isentropic Compressibilities for 1,3-Dioxolane or 1,4-Dioxane + Water + Formamide or N,N-Dimethylformamide Ternary Mixtures at 308.15 K

Abstract

Speeds of sound, uijk, of 1,3-dioxolane or 1,4-dioxane (i) + water (j) + formamide or dimethylformamide (k) ternary mixtures and of their binary subsystems, uij, of 1,3-dioxolane or 1,4-dioxane (i) + formamide or dimethylformamide (j), and water (i) + formamide or dimethylformamide (j) have been measured over the entire composition range at 308.15 K. The experimental data have been used to evaluate the excess isentropic compressibilities of binary (κsE)ij and ternary (κsE)ijk mixtures using their densities calculated from molar excess volume data. The Moelwyn-Huggins concept [M. L. Huggins, Polymer12, 389 (1971)] of interaction between the surfaces of components of a binary mixture has been employed to evaluate the excess isentropic compressibilities (using the concept of connectivity parameter of third degree of a molecule, 3ξ, which in turn depends on its topology) of binary mixtures, and this method has been extended to predict excess compressibilities of ternary mixtures. Values of (κsE)ij and (κsE)ijk have also been calculated by the Flory theory. It was observed that (κsE)ij and (κsE)ijk predicted by the Moelwyn-Huggins approach compare well with calculated and experimental values.