Abstract
We report on a new class of highly fluid ionic liquids integrating a cation that resembles an opened imidazolium structure with two distinct anions, bis(trifluoromethylsulfonyl)imide, [Tf 2N], and a nitrile-containing anion, [C(CN) 3]. These new ionic liquids show exceptional CO 2 permeability values in liquid membrane gas separations with results that equal or exceed the Robeson upper bound. Moreover, these ionic liquids offer ideal CO 2/N 2 selectivities competitive with the best results reported to date, exhibiting values that range from 28 to 45. The nitrile containing ionic liquid displayed the highest ideal CO 2/N 2 selectivity with a value of 45 which primarily results from a reduction in the nitrogen permeability. In addition to permeability results, CO 2 solubilities were also measured for the this new class of ionic liquids with values similar to the popular 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. The CO 2 solubility results were compared to predicted values obtained using both a modified regular solution theory and the quantum chemical Conductor-like Screening Model for Real Solvents (COSMO-RS) method. Agreement between predicted and measured solubility values is also discussed.
Original language | English |
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Pages (from-to) | 61-67 |
Number of pages | 7 |
Journal | Journal of Membrane Science |
Volume | 401-402 |
DOIs | |
State | Published - May 15 2012 |
Funding
This work was fully sponsored by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy.
Keywords
- Gas separations
- Membranes
- Supported ionic liquids