Topological investigation of ternary mixtures: Excess heat capacities

Excess heat capacities of binary, (CPE)12 1,3-dioxolane (1) + 1,4-dioxane (2) and ternary, (CPE)123 of 1,3-dioxolane (1) + N-methylpyrrolidin-2-one or 1,4-dioxane (2) + cyclohexanone or cycloheptanone (3) mixtures have been determined by using their measured molar heat capacities, (CP)12, (CP)123 data over temperature range from 293.15 to 308.15 K with 5 K interval under atmospheric pressure. The (CPE)123 data for all the investigated mixtures at the studied temperatures are positive throughout the compositions of (1) and (2) and are increasing with increase in temperature. The data have been rationalized in terms of Graph and Flory's theories. It has been observed that (CPE)123 values predicted by Graph theory compare well with their corresponding experimental values. However, Flory theory correctly predicts the sign of (CPE)123 1,3-dioxolane (1) + N-methylpyrrolidin-2-one (2) + cyclohexanone or cycloheptanone (3) and 1,3-dioxolane (1) + 1,4-dioxane (2) + cycloheptanone (3) mixtures.