An experimental and theoretical study on 2-hydroxyethylammonium acetate ionic liquid

Abstract The physicochemical properties, microstructuring and intermolecular forces of 2-hydroxyethylammonium acetate protic ionic liquid have been studied using a combined experimental and theoretical approach. Relevant thermophysical properties (density, speed of sound, dynamic viscosity, surface tension and refraction index) were measured as a function of temperature and analyzed in terms of fluid's behavior. The solubility parameter of the considered protic ionic liquid was also estimated at different temperatures according to Eyring's approach. Theoretical studies using both quantum chemistry (density functional theory) and classical molecular dynamics simulations were carried out and were analyzed in terms of the characteristics of hydrogen bonding and their effect on ionic liquid behavior. Likewise, simulations at vacuum interface and the effect of water content on the fluid's microstructuring were also considered. The reported results provide a detailed picture of 2-hydroxyethylammonium acetate allowing a deeper understanding of the properties of protic ionic liquids.