Journal of Chemical and Engineering Data, Vol.66, No.1, 101-115, 2021
Comparative Study of Influence of Ethanol and 2,2,2-Trifluoroethanol on Thermophysical Properties of 1-Ethyl-3-methylimidazolium Dicyanamide in Binary Mixtures: Experimental and MD Simulations
This work focuses on studying the influence exerted on several thermophysical properties of an ionic liquid (IL), 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]) by alcoholic solvents, ethanol and 2,2,2-trifluoroethanol (TFE), experimentally and computationally. Herein, the densities, rho, speeds of sound, u, and dynamic viscosities, eta, of the pure IL, [EMIM][DCA]; molecular solvents, ethanol and TFE; and their binary mixtures have been measured over the entire mole fraction ranges at various temperatures from 298.15 to 323.15 K, with an interval of 5 K and at pressure P = 0.1 MPa. The obtained experimental data are utilized to determine the excess/deviation properties, viz., the excess molar volumes, V-F, isentropic compressibility deviations, Delta K-s, and viscosity deviations, Delta(eta). The excess/deviation properties of the studied binary mixtures are fitted to polynomial equations of Redlich-Kister type. The dependence of computed parameters on the composition and temperature and the nature of studied systems is discussed in terms of ion-ion, ion-dipole, hydrogen-bonding, and dipole-dipole interactions. The excess molar volumes of each binary system have been correlated with Prigogine-Flory-Patterson theory. To obtain a molecular-level understanding of the interactions between the IL and cosolvent, molecular dynamics (MD) simulations are employed for two different systems as a function of composition at two different temperatures. Along with thermophysical properties such as density and excess molar volume, the self-diffusion coefficient, radial distribution function, and coordination number are also obtained from MD to provide further insights into fluorine-substituted ethanol (TFE) with IL in order to understand the effect of substitution of fluorine in ethanol in the IL + solvent binary systems.