Viscosities for Ionic Liquid Binary Mixtures with a Common Ion

At present, there is a considerable amount of work devoted to the study of the thermophysical properties of pure ionic liquids, which contrasts with the few data available for their mixtures. One of the most appealing characteristics of ionic liquids is the capability of subtly changing the chemical structure of the cation and anion in order to design appropriate solvents for specific applications. Mixtures of ionic liquids increase enormously this specificity, due to the unlimited combinations that arise from mixing two or more ionic liquids. In this context, the study of the thermophysical properties of these mixtures is revealed as a fundamental task. In this work the viscosities of the ionic liquid binary mixtures with a common ion ([C6mim] + [C2mim])[BF4], ([C6mim] + [C4mim])[BF4], [C4mim]([BF4] + [MeSO4]) and [C4mim]([PF6] + [BF4]) were determined within the temperature range (298.15–308.15) K. The temperature dependence of the viscosity for pure liquids is analyzed by means of the Vogel-Tammann-Fulcher equation and several mixing rules are applied for the mixtures.