Correlation of liquid–liquid equilibrium for binary and ternary systems containing ionic liquids with the tetrafluoroborate anion using ASOG

Abstract

Ionic liquids are neoteric, environmentally friendly solvents (since they do not produce emissions) composed of large organic cations and relatively small inorganic anions. They have favorable physical properties, such as negligible volatility and wide range of liquid existence. Liquid–liquid equilibrium (LLE) data for systems including ionic liquids, although essential for the design, optimization and operation of separation processes, are still scarce. However, some recent studies have presented ternary LLE data involving several ionic liquids and organic compounds such as alkanes, alkenes, alkanols, water, ethers and aromatics. In this work, the ASOG model for the activity coefficient is used to predict LLE data for 15 binary and 09 ternary systems at 101.3kPa and several temperatures; all the systems are formed by ionic liquids including the tetrafluoroborate anion plus alkanes, alkanols, water, ethers, esters and aromatics. New group interaction parameters were determined using a modified Simplex method, minimizing a composition-based objective function of experimental data obtained from literature. The results are satisfactory, with rms deviations of about 3%.