Thermodynamic properties of binary mixtures of n-butylammonium-based ionic liquids with ethanol at T = (293.15–313.15) K

Abstract

© 2018, Akadémiai Kiadó, Budapest, Hungary. In this study, density, speed of sound and viscosity of binary mixtures of ionic liquids + ethanol have been measured as a function of composition at T = (293.15–313.15) K and atmospheric pressure. The ionic liquids studied were: {n-butylammonium acetate (N4Ace), n-butylammonium propanoate (N4Pro), n-butylammonium hexanoate (N4Hex), and n-butylammonium decanoate (N4Dec)}. Excess molar volume, VmE, deviation in isentropic compressibility, Δ κ S , deviation in viscosity, Δ η, and excess Gibbs energy of activation of viscous flow, Δ G ∗ E , were obtained from experimental results and correlated with the Redlich–Kister polynomial equation. Ionic liquids were synthesized and characterized using 1 H-NMR, 13 C-NMR and FTIR spectroscopy techniques. For all systems studied, the values of VmE, Δ κ S and Δ η were negative over the entire composition range, whereas Δ G ∗ E values were positive over the entire composition range. The results obtained were discussed in terms of structural effects and intermolecular interactions between like and unlike molecules.