(437g) Anion Effect on the Thermophysical and Transport Properties of Binary Ionic Liquid Mixtures

It has been well-known that ionic liquids are designer solvents as the constituent cation, anion or functional groups on cations can be varied to achieve desired thermophysical, chemical and biological properties. Recently another dimension in terms of binary ionic liquid mixtures has emerged as a way to dramatically expand the range of available ionic liquids allowing us to further fine tune ionic liquid properties. As one can envision a large number of ionic liquid mixtures with varying compositions, it’s highly desirable to predict whether such mixture properties can be predicted from the knowledge of the corresponding pure ionic liquid properties, i.e., if binary ionic liquid mixtures form ideal solutions. On the other hand, it is equally important to determine molecular factors that lead to non-ideal behavior. In this talk, we will provide molecular level insight into ideal/non-ideal behavior of binary ionic liquid mixtures by predicting their thermophysical and transport properties. In particular, we will focus on the cation 1-n­-butyl-3-methylimidazolium [C₄mim]⁺ in combination with three binary mixtures of the anions: chloride (Cl^-) and methylsulfate, Cl^- and bis(trifluoromethanesulfonyl)imide, Cl^- and ethylsulfate. We will present results on the excess molar volumes and mixture diffusivities. The variation of these properties as a function of mole fractions of the anions will be discussed in conjunction with structural features of the systems expressed in the form of radial distribution functions and three dimensional probability distribution plots of the anions around the cation [C₄mim]⁺.