Topological investigations of thermodynamic properties of ionic liquid mixtures: Excess molar volumes and excess isentropic compressibilities

The densities, ρ, speeds of sound, u, and heat capacities, Cp of pure 1-ethyl-3-methylimidazolium tetrafluoroborate, aniline, N-methylaniline, 2-methylaniline and 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + 2-methylaniline (j) + aniline or N-methylaniline (k) ternary and their 2-methylaniline (j) + aniline or N-methylaniline (k) binary mixtures have been measured as a function of composition at 293.15, 298.15, 303.15, 308.15 K and atmospheric pressure. The observed densities and speeds of sound data have been employed to determine excess molar volumes, VE and excess isentropic compressibilities, κSE of the investigated mixtures. The observed thermodynamic properties of the binary as well as ternary mixtures have been calculated by utilizing the topology of the constituents of mixtures (graph theory). It has been observed that graph theory successfully describes well the VE and κSE data of the studied binary as well as ternary ionic liquid mixtures.