Abstract:

An ionic liquid(IL) EMIFeCl₄ was prepared by directly mixing FeCl₃ and 1-methyl-3-ethylimidazolium chloride with a molar ratio 1/1 under dry argon atmosphere. The densities, and surface tension of the pure IL were determined in the temperature range from 293.15 K to (343.15±0.1) K. The properties for the ionic liquids were discussed by using Glasser′s theory. The crystal energy of ionic liquid is much lower than ionic solid and this is the underlying reason for forming ionic liquid at room temperature. In addition, a new theoretical model of ionic liquid, that is interstice model, was applied to calculating the thermal expansion coefficient of EMIFeCl₄. And the magnitude order of the thermal expansion coefficient, α, calculated by the theoretical model is in good agreement with experimental value. The result shows that there is much reasonableness for the interstice model of ionic liquid.

Key words: Ionic liquid; Density; Surface tension; FeCl₃; Interstice model