Thermodynamic properties of binary mixtures of tetrahydropyran with pyridine and isomeric picolines: Excess molar volumes, excess molar enthalpies and excess isentropic compressibilities

Densities, ρ and speeds of sound, u of tetrahydropyran (i) + pyridine or α-, β- or γ- picoline (j) binary mixtures at 298.15, 303.15 and 308.15 K and excess molar enthalpies, HE of the same set of mixtures at 308.15 K have been measured as a function of composition using an anton Parr vibrating-tube digital density and sound analyzer (model DSA 5000) and 2-drop micro-calorimeter, respectively. The resulting density and speed of sound data of the investigated mixtures have been utilized to predict excess molar volumes, VE and excess isentropic compressibilities, κSE. The observed data have been analyzed in terms of (i) Graph theory; (ii) Prigogine–Flory–Patterson theory. It has been observed that VE, HE and κSE data predicted by Graph theory compare well with their experimental values.

Research highlights
► Densities, ρ and speeds of sound, u of tetrahydropyran (i) + pyridine or α-, β- or γ-picoline (j) binary mixtures at 298.15, 303.15 and 308.15 K and excess molar enthalpies, HE of the same set of mixtures at 308.15 K have been measured as a function of composition.
► The observed densities and speeds of sound values have been employed to determine excess molar volumes, VE and excess isentropic compressibilities, κSE.
► Topology of the constituents of mixtures has been utilized (Graph theory) successfully to predict VE, HE and κSE data of the investigated mixtures.
► Thermodynamic data of the various mixtures have also been analyzed in terms of Prigogine–Flory–Patterson (PFP) theory.