Abstract
This work presents the results of the use of a Group Contribution Equation of State (GC-EOS) to model experimental data obtained for ternary systems of the type bmim[BF4] + organic solute + CO2 with four different organic compounds, namely acetophenone, 1-phenylethanol, 4-isobutylacetophenone, and 1-(4-isobutylphenyl)-ethanol. Our results show that the GC-EOS is able to qualitatively predict not only L+V -> L but also L-1+L-2 -> L phase transitions. As the two two-phase boundaries L+V and L-1+L-2 of the experimentally found three-phase region L-1+L-2+V almost coincide with the saturated vapor pressure curve of pure CO2, the phase transitions L+V -> L-1+L-2+V and L-1+L-2+V -> L-1+L-2 have been represented as this vapor-pressure curve by the model. The average absolute deviations between experimental and predicted values for all phase transitions have been found to be very satisfactory. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 1265-1273, 2009