Density and refractive index measurements of 1-ethyl-3-methylimidazolium-based ionic liquids

This work was the continuation of our previous study where the correlations between density and refractive index of pure systems of ionic liquids were examined. The density and refractive index of five 1-ethyl-3-methylimidazolium-based ionic liquids were measured at standard pressure and temperature up to 353.2 K. Densities and refractive indices of the studied ionic liquids were presented as a function of temperature. A group contribution-based equation was used to represent the temperature dependence of density and refractive index. The Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, and Newton equations, as well as a modified Eykman were used to correlate the relation between the measured densities and refractive indices. The correlations give satisfactory results.