Steve R. Lustig, Central Research & Development, The DuPont Company, Experimental Station, Route 141, Wilmington, DE 19880-0356, Mark B. Shiflett, Central Research and Development, The DuPont Company, Experimental Station, Route 141, Wilmington, DE 19880-0356, and Akimichi Yokozeki, DuPont Fluoroproducts Laboratory, The DuPont Company, Experimental Station, Route 141, Wilmington, DE 19880-0356.
We have carried out predictions of the vapor-liquid equilibria (VLE) of various hydrofluorocarbons (HFCs) in room-temperature ionic liquids (RTILs) using a conductor-like screening model (COSMO-RS) and the quantum mechanical package (TURBOMOLE)[1]. The VLE of HFCs in RTILs were measured using a gravimetric microbalance at temperatures from 283 to 348 K and pressures from 0.01 to 2 MPa [2-4]. Activity coefficients at infinite dilution and Henry's law constants are predicted and compared with measurements for the present systems [2,5]. Qualitative agreement of the gas solubility of HFCs in RTILs will be shown. Henry's law constants for the methane and ethane series were predicted in the correct order (CH2F2 < CH3F < CF3H < CF4 and CH2FCF3 < CHF2CH3 < CH2FCH3 < CHF2CF3 < CF3CH3) and are in semiquantitative agreement with the measurements. In addition to the measured phase behavior, we will discuss a novel approach to design ionic liquids using COSMO-RS theory. In this approach we predict the solvent's chemical structure required to provide desired bounds for one or more mixture properties.
[1] A. Klamt, COSMO-RS From Quantum Chemistry to Fluid Phase Thermodynamics and Drug Design, Elsevier, New York, 2005. [2] M. B. Shiflett and A. Yokozeki, AIChE J. 52(3) (2006) 1205-1219. [3] M.B. Shiflett, M.A. Harmer, C.P. Junk, A. Yokozeki, J. Chem. Eng. Data. 51(2) (2006) 483-495. [4] M.B. Shiflett, M.A. Harmer, C.P. Junk, A. Yokozeki, Fluid Phase Equilibr. 242 (2006) 220-232. [5] M.B. Shiflett and A. Yokozeki, Ind. Chem. Eng. Res. (2006) submitted.
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