(382ac) Structural and Transport Properties of the Mixtures of Ionic Liquid 1-Ethyl-3-Methylimidazolium Dicyanamide and Trifluoroethanol from Molecular Simulations

Ionic Liquids are one of the widely studied solvents for various applications such as gas separation agents, reaction media, electrolytes, and propellent fuels in rocket science. To overcome transport limitations in many ionic liquids, due to high viscosity and slow diffusion coefficients, researchers have adopted an approach of adding common solvents for lowering the viscosity and enhancing transport. 2,2,2-trifuoroethanol (TFE) is an interesting cosolvent as it can coordinate with the anion and cation of ionic liquids due to its strong hydrogen bond acidity. Moreover, TFE also has almost zero hydrogen bond basicity. In the present work, we use molecular simulations to probe how the molecular level interactions between the ions of 1-ethyl-3-imidazolium [EMIM] dicyanamide [DCA] change with the addition of TFE. This system is particularly interesting because [EMIM][DCA] is known to have one of the lowest viscosity in the imidazolium cation family, while TFE is an acidic alcohol with negligible hydrogen accepting ability. We will demonstrate that the self-diffusion coefficient of the ionic liquid enhances almost two orders of magnitude as the concentration of TFE increases. We will also show that the distribution of TEF around [DCA] changes dramatically at that the 1:2 molar ratio of [EMIM][DCA] to TFE.