Physicochemical Study of n-Ethylpyridinium bis(trifluoromethylsulfonyl)imide Ionic Liquid

In this work, thermophysical properties of n-ethylpyridinium bis(trifluoromethylsulfonyl)imide have been studied at atmospheric pressure in the temperature range 288.15–338.15 K. Density, speed of sound, refractive index, surface tension, isobaric molar heat capacity, electrical conductivity and kinematic viscosity have been measured; from these data the isobaric expansibility, isentropic compressibility, molar refraction, entropy and enthalpy of surface formation per unit of surface area, and dynamic viscosity have been calculated. Moreover, we have characterized the thermal behavior of the compound. Results have been analyzed paying special attention to the structural and energetic factors. The magnitude and directionality of the cation–anion interactions have been studied using ab initio quantum calculations, which allow a better understanding of the physicochemical behavior of the ionic liquid. Finally, density values and radial distribution functions were also estimated ab initio from classical molecular dynamics simulations, providing acceptable density predictions.