Experimental Measurements and Modeling Using tPC-PSAFT of the Phase Behavior of the Ternary Ionic Liquid System

The phase behavior of the ternary ionic liquid system 1-butyl-3-methylimidazolium nitrate ([bmim][NO3]) + carbon dioxide (CO2) + water (H2O) was studied experimentally using a synthetic method. Bubble-point pressures are measured for carbon dioxide concentrations ranging from 5 to 30 mole%, water concentrations ranging from 2 to 20 mole% and within a temperature range of 293 to 368 K. Thereafter, the phase behavior of this ternary system was modeled with the truncated Perturbed Chain Polar Statistical Association Fluid Theory (tPC-PSAFT) equation of state, which was recently developed for prediction of the phase behavior of binary ionic liquid systems. Here, this equation of state has been extended to ternary ionic liquid systems, so that the model is able to predict the phase behavior of the ternary system [bmim][NO3] + CO2 + H2O. In general, good agreement with experimental data is obtained.