Thermodynamic properties of ternary mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate with 1-methyl pyrrolidin-2-one or pyrrolidin-2-one + water

Densities, rho(ijk) and speeds of sound, u(ijk) of 1-ethyl-3-methylimidazolium tetrafluoroborate (i) + 1-methyl pyrrolidin-2-one or pyrrolidin-2-one (j)+ water (k) ternary mixtures have been measured over the complete mole fraction range at 293.15, 298.15, 303.15, and 308.15 K using density and speed of sound analyzer (Anton Paar DSA 5000). The heat capacity, Cp of water at 293.15, 298.15, 303.15, and 308.15 K have also been measured using differential scanning calorimeter (Model - mu DSC 7 Evo). The measured data have been employed to determine excess molar volumes, V-ijk(E) and excess isentropic compressibilities, (kappa(E)(S))(ijk). The V-ijk(E) and (kappa(E)(S))(ijk) data have been fitted to Redlich-Kister equation to calculate ternary adjustable parameters and standard deviations. The observed thermodynamic properties of the ternary mixtures have been analyzed in terms of Graph theory. It has been observed that Graph theory successfully describes well V-ijk(E) and (kappa(E)(S))(ijk) data of the studied ternary ionic liquid mixtures. (C) 2013 Elsevier B.V. All rights reserved.