Evaluation of Solution Thermodynamic Properties of Mixed Ionic Liquids at Different Temperatures (293.15–343.15) K

Abstract

The solution thermodynamic properties of mixed ionic liquids such as density, excess molar volume, partial molar volume and apparent molar volume are highly influential on the design of an effective separation unit and in the optimization of operating parameters like pressure, temperature and concentration for the separation processes. Therefore, it could be better to do a prior experimental study on of the solution thermodynamic properties of mixed ionic liquids at different temperatures for the whole mole fractions rather than doing separation characterization studies like selectivity, efficiency, distribution coefficient and performance index. In addition, the recovery and regeneration of ionic liquids also challenge researchers and separation scientists in several fields of applications. Therefore, in this chapter, density of pure 1-butyl-3-methyl imidazolium bis (trifluoromethylsulfonyl) imide {[BIMIM][NtF 2 ]}, 1-ethyl-3-methylimidazolium ethyl sulfate {[EMIM][ESO 4 ]}, 1-ethyl-3-methylimidazolium hydrogen sulfate {[EMIM][HSO 4 ]} and 1-butyl-3-methylimidazolium acetate {[BMIM][OAc]} and its binary mixtures have been measured at T (293.15-343.15) K. From the measured densities, isobaric expansivity, excess molar volume, partial molar volume, excess partial molar volume, and apparent molar volume have been calculated. Results were discussed in terms of physical interaction, chemical interaction and structural orientation at molecular level and their temperature and composition dependency.