(262ag) Volumetric, Acoustic and Viscometric Properties of Binary Mixtures of (n-Butylammonium based ionic liquid + Ethanol) at Different Temperatures

In this work, experimental data of density, speed of sound and viscosity for binary mixtures of {ethanol + n-butylammonium methanoate, or + n-butylammonium acetate, or + n-butylammonium propanoate l, or + n-butylammonium oleate, or + n-butylammonium decanoate, or + n-butylammonium hexanoate ionic liquid} have been determined as a function of composition at T = (293.15 - 313.15) K. The results were used to calculate the excess molar volume, V^E , deviation in isentropic compressibility, Î?k_s , deviation in viscosity, Î?η, and excess Gibbs free energy of activation of viscous flow, Î?G^*E, and correlated to the Redlich-Kister polynomial equation. Ionic liquids were synthesized by the method of acid-base neutralization reaction using n-butylamine and formic acid, or acetic acid, or propionic acid, or oleic acid, or decanoic acid, or hexanoic acid. N-Butylamine (Merck, purity > 99.0%), formic acid (Merck, purity > 98.0%), acetic acid (Merck, purity > 100%), or propionic acid (Sigma-Aldrich, purity > 99.5%), or oleic acid (Sigma-Aldrich or Fluka, purity > 65,0%), decanoic acid (Merck, purity > 98.0%), hexanoic acid (Merck, purity > 98.0%) were used without further purification. Ionic Liquids were characterized by using ¹H-NMR, ¹³C-NMR and FTIR spectroscopy techniques.

The binary mixtures were prepared by weighing the pure components using an electronic balance manufactured by Shimadzu (Model AUY220). The densities and speed of sound of pure components and their solutions were measured using a commercial density and speed of sound analyzer manufactured by Anton Paar (Model DSA5000) The viscosities were measuring using a Stabinger viscometer manufactured by Anton Paar (Model SVM3000/G2). The analysis of ¹H-NMR and ¹³C-NMR were obtained in an Avance III 600 HD Bruker spectrometer operating at 500 MHz for protons and 125 MHz for carbon. The IR spectra were obtained in Fourier transform infrared spectroscopy Nicolet with attenuated total reflectance (FTIR-ATR) (Model 6700).

For all systems studied, the values of excess molar volumes, deviation in isentropic compressibility and deviation in viscosity were negative over the entire composition range. The values of excess Gibbs free energy of activation of viscous flow were positive over the entire composition range. The results obtained were discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules.