Thermodynamics of ternary mixtures of non-electrolytes: excess volumes

Molar excess volumes, [Formula: see text], of some (i + j + k) ternary mixtures of non-electrolytes have been determined dilatometrically at 298.15 and 308.15 K and the same have been analysed in terms of (a) Lacombe and Sanchez theory and (b) an approach based on the mathematical discipline of graph theory utilizing information on the (i + j), (j + k), and (k + i) binary mixtures alone. It has been observed that the [Formula: see text] data predicted by the graph theoretical approach employing the graph theoretical binary interaction coefficients αij, αjk, and αki compare better with the corresponding experimental values than the [Formula: see text] values predicted by Lacombe and Sanchez theory utilizing Lacombe and Sanchez's binary interaction coefficients χij, χjk, and χki of the (i + j), (j + k), and (k + i) mixtures. The [Formula: see text] data have also been utilized to extract, via the Mayer–McMillan approach, self and cross volume interaction coefficients Vjj, Vkk, Vjk. Vjjk, and Vjkk and the Vjk values have been utilized to study molecular interactions between the jth and the kth components in the presence of the ith component of these (I + j + k) mixtures.