TY - JOUR

T1 - Equation of state modelling of systems with ionic liquids: Literature review and application with the Cubic Plus Association (CPA) model

A1 - Maia,Filipa Meireles

A1 - Tsivintzelis,Ioannis

A1 - Rodriguez,Oscar

A1 - Macedo,Eugénia A.

A1 - Kontogeorgis,Georgios

AU - Maia,Filipa Meireles

AU - Tsivintzelis,Ioannis

AU - Rodriguez,Oscar

AU - Macedo,Eugénia A.

AU - Kontogeorgis,Georgios

PB - Elsevier BV

PY - 2012

Y1 - 2012

N2 - <p>For the last decade ionic liquids have been regarded as compounds of interest by the academic and industrial communities. These compounds present several advantages when compared to other typical solvents. However, because of their novelty, a deep understanding of their phase behaviour and their interactions with other components is still needed. In this work, we made a review of literature studies on modelling systems with ionic liquids using equation of state models. Furthermore, we applied the Cubic Plus Association (CPA) equation of state to describe the phase behaviour of two ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₂mim][NTf₂]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([C₄mim][NTf₂]). The first step was to study an adequate approach for the determination of pure component parameters for the ionic liquids. The parameters were obtained by fitting the predictions of the model to experimental vapour pressure and liquid density data. The parameters provide a good description of both experimental vapour pressures and liquid density, with maximum percentage deviations of respectively 8.9 and 1.3% for [C₂mim][NTf₂] and 5.7 and 0.5% for [C₄mim][NTf₂]. Different sets of pure component parameters for each ionic liquid were considered and their suitability to describe the behaviour of ionic liquids was evaluated by modelling the vapour–liquid equilibria (VLE) of mixtures with CO₂ and the liquid–liquid equilibria (LLE) with water. The results for VLE proved to be very good in the range of pressures studied when using one temperature-independent binary interaction parameter, with percentage deviations in pressure between 8 and 13% for [C₂mim][NTf₂] and around 12% for [C₄mim][NTf₂]. For the LLE of ionic liquids with water a temperature-independent binary interaction parameter was also used, but the results do not describe the experimental data as well as with the VLE, with percentage deviations ranging from 4 to 100%. However, for some of the sets of pure component parameters a good description of the experimental data is obtained and work is in progress for improving the modelling of LLE with the CPA equation of state.</p>

AB - <p>For the last decade ionic liquids have been regarded as compounds of interest by the academic and industrial communities. These compounds present several advantages when compared to other typical solvents. However, because of their novelty, a deep understanding of their phase behaviour and their interactions with other components is still needed. In this work, we made a review of literature studies on modelling systems with ionic liquids using equation of state models. Furthermore, we applied the Cubic Plus Association (CPA) equation of state to describe the phase behaviour of two ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C₂mim][NTf₂]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([C₄mim][NTf₂]). The first step was to study an adequate approach for the determination of pure component parameters for the ionic liquids. The parameters were obtained by fitting the predictions of the model to experimental vapour pressure and liquid density data. The parameters provide a good description of both experimental vapour pressures and liquid density, with maximum percentage deviations of respectively 8.9 and 1.3% for [C₂mim][NTf₂] and 5.7 and 0.5% for [C₄mim][NTf₂]. Different sets of pure component parameters for each ionic liquid were considered and their suitability to describe the behaviour of ionic liquids was evaluated by modelling the vapour–liquid equilibria (VLE) of mixtures with CO₂ and the liquid–liquid equilibria (LLE) with water. The results for VLE proved to be very good in the range of pressures studied when using one temperature-independent binary interaction parameter, with percentage deviations in pressure between 8 and 13% for [C₂mim][NTf₂] and around 12% for [C₄mim][NTf₂]. For the LLE of ionic liquids with water a temperature-independent binary interaction parameter was also used, but the results do not describe the experimental data as well as with the VLE, with percentage deviations ranging from 4 to 100%. However, for some of the sets of pure component parameters a good description of the experimental data is obtained and work is in progress for improving the modelling of LLE with the CPA equation of state.</p>

KW - Equation of state

KW - Cubic Plus Association

KW - Phase equilibria

KW - Ionic liquids

KW - Carbon dioxide

KW - Water

U2 - 10.1016/j.fluid.2012.06.026

DO - 10.1016/j.fluid.2012.06.026

JO - Fluid Phase Equilibria

JF - Fluid Phase Equilibria

SN - 0378-3812

VL - 332

SP - 128

EP - 143

ER -