The stochastic global optimization methods have been extensively used in the fluid phase equilibrium
calculations. Among these methods, Genetic Algorithm (GA) can be applied to calculate fitting
parameters of activity coefficient models in equilibrium systems. In the present work, based on the GA
method, the parameters of NRTL and Two-Suffix Margules models have been calculated for 20 ternary
extraction systems containing ionic liquids. The values of the parameters of these models along with the
root mean square deviations (rmsd) are reported. The obtained results, in terms of rmsd for these models
are satisfactory, with the overall values of 0.0039 and 0.0195 for 169 tie-lines for NRTL and Two-Suffix
Margules models, respectively.
