(239c) Property Prediction of Ionic Liquid Solutions Using Cosmo-Rs

The COSMO-RS method is an efficient statistical thermodynamic procedure, which is based on the quantum chemical COSMO model. Although developed and parameterized exclusively on neutral compounds, COSMO-RS has been proven by several groups to be well applicable to the fluid phase thermodynamics of ILs.1 One of the first applications of COSMO-RS to the calculation of properties of solutes in ionic liquids was the prediction of activity coefficients at infinite dilution of solutes in ionic liquids.2 Further applications, like the calculation of liquid-liquid equilibria of ionic liquid with alcohols, followed.3 Since for neutral compounds COSMO-RS is well able to predict vapor pressures with an accuracy better than 0.5 log units, the question was raised if it would be able to predict the very low vapor pressures of ionic liquids as well. A first study on the vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide showed that the calculated enthalpies are in good agreement with the experimental data, whereas COSMO-RS seems to underestimate the vapor pressures.4 In this talk we will give an overview of the application of COSMO-RS on the field of property prediction of ionic liquid phase thermodynamics with special focus on the vapor pressure prediction.

1) T. Banerjee, and A. Khanna, J. Chem. Eng. Data, 2006, 51, 2170-2177. C. Jork, C. Kristen, D. Pieraccini, A. Stark, C. Chiappe, Y.A. Beste, and W. Arlt, J. Chem. Thermodyn., 2005, 37, 537-558. 2) M. Diedenhofen, F. Eckert, and A. Klamt, J. Chem. Eng. Data, 2003, 48, 475-479. 3) Urszula Domanska, Aneta Pobudkowska and Frank Eckert, The Journal of Chemical Thermodynamics, 38, 685-695 (2006). 4) M. Diedenhofen, A. Klamt, K. Marsh and A. Schäfer, submitted.