Density, Viscosity, and Conductivity of Lewis Acidic 1‑Butyl- and 1‑Hydrogen-3-methylimidazolium Chloroaluminate Ionic Liquids

To promote the development of Lewis acidic chloroaluminate ionic liquids, it is necessary to get a deeper insight into their physicochemical properties and molecular structure. In this work, the densities, viscosities, and conductivities of acidic 1-butyl- and 1-hydrogen-3-methylimidazolium chloroaluminate with different mole fractions of AlCl3 were measured in the temperature range from (293.15 to 343.15) K. Meanwhile, excess molar volume and viscosity deviation values for the binary mixtures of 1-butyl-3-methylimidazolium chloroaluminate ionic liquids were also obtained. All of the experimental data were well-fitted by the empirical equations. Based on the results of density functional theory calculations, the differences in these properties are attributed to the molecular structure, cation–anion interaction, and hydrogen bonds of ionic liquids. It is expected that the present study may be deemed useful for the application of Lewis acidic chloroaluminate ionic liquids in electrochemistry and catalysis.