Thermodynamic and topological investigations of ternary mixtures with o-toluidine, tetrahydropyran, and picolines: Excess molar volume and excess isentropic compressibility

The density, ρijk and speed of sound, uijk, ternary {o-toluidine (i) + tetrahydropyran (j) + α-, β-, or γ-picoline (k)} mixtures have been measured over the entire composition range at T = (298.15, 303.15, and 308.15) K. The excess molar volume, VijkE and excess isentropic compressibility, (κSE)ijk values of the mixtures have been predicted by using the experimental results. The observed thermodynamic properties have been fitted to Redlich–Kister equation to determine ternary adjustable parameters and standard deviations. The VijkE and (κSE)ijk values have also been analyzed in terms of (1) Graph theory and (2) Prigogine–Flory–Patterson theory (PFP). It has been observed that VijkE and (κSE)ijk data determined by Graph theory compare well with experimental values.

► The ρijkρijk and uijkuijk data of ternary (OT + THP + α-, or β-, or γ-picolines) mixtures, measured at three temperatures. ► The ρijkρijk and uijkuijk data of the studied ternary mixtures have been employed to determine their VijkE and (κSE)ijk values. ► The VijkE and (κSE)ijk values have been fitted to Redlich–Kister equation. ► The VijkE and (κSE)ijk data has been analyzed in terms of Graph and PFP theories. ► It has been observed that Graph theory correctly predicts the sign as well as magnitude of VijkE and (κSE)ijk.