Anion Effects on Gas Solubility in Ionic Liquids
Abstract
This work presents the results of solubility measurements for a series of gases in 1-n-butyl-3-methyl imidazolium tetrafluoroborate and 1-n-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl) imide. The gases considered include benzene, carbon dioxide, nitrous oxide, ethylene, ethane, oxygen, and carbon monoxide. Carbon dioxide and oxygen solubilities are also reported in methyl-tributylammonium bis(trifluoromethylsulfonyl) imide, butyl-methyl pyrrolidinium bis(trifluoromethylsulfonyl) imide, and tri-isobutyl-methyl phosphonium p-toluenesulfonate. We report the associated Henry's constants and enthalpies and entropies of absorption. In general, benzene, followed by carbon dioxide and nitrous oxide, have the highest solubilities and strongest interactions with the ionic liquids, followed by ethylene and ethane. Oxygen had very low solubilities and weak interactions. Carbon monoxide had a solubility below the detection limit of our apparatus. Ionic liquids with the bis(trifluoromethylsulfonyl) imide anion had the largest affinity for CO_2, regardless of whether the cation was imidazolium, pyrrolidinium, or tetraalkylammonium. These results suggest that the nature of the anion has the most significant influence on the gas solubilities.
Additional Information
© 2005 American Chemical Society. Received 10 August 2004. Published online 11 March 2005. Published in print 1 April 2005. Funding for this research was provided by the Indiana 21st Century Technology Fund and the National Science Foundation (CTS-9987627). We thank Jacob M. Crosthwaite for synthesizing and purifying the [bmim][BF_4] sample and Dr. Sudhir N.V.K. Aki for synthesizing and purifying the [bmim][Tf_2N] sample. We also thank Dr. Tom Welton and Paul Smith for the [bmim][BF_4] sample, and Dr. Pedi Neta for the [MeBu_3N][Tf_2N], [HeBu_3N][Tf_2N], and [MeBuPyrr][Tf_2N] samples.Attached Files
Supplemental Material - jp046404lsi20041221_091742.pdf
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Additional details
- Eprint ID
- 77699
- Resolver ID
- CaltechAUTHORS:20170524-092031044
- Indiana 21st Century Technology Fund
- CTS-9987627
- NSF
- Created
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2017-05-24Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field