A potential ionic liquid for CO2-separating gas membranes: selection and gas solubility studies

The production of hydrogen from fossil fuels by steam reforming/water gas shift can be enhanced by separating the reaction byproduct, CO2, within the reactor as it is produced. Such a separation-enhanced reaction not only has higher conversion efficiency, but can also be considered a greener process which produces high-purity hydrogen with little CO2 contamination. Supported ionic liquid membranes may be able to achieve this separation task since they are known to have high CO2 and low H2 solubilities. In this study, the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide family of ionic liquids has been selected for this purpose, based on limited literature data. The solubilities of major reaction gases, namely CO2, H2, CO, and CH4, in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide are compared to one another. In addition, the solubilities of CO2 and H2 in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide are compared. The results indicate, from a thermodynamic point of view, the possibility of using this family of ionic liquids as separation membranes with practical CO2/H2 selectivities.

[1]  S. Incerti,et al.  Geant4 developments and applications , 2006, IEEE Transactions on Nuclear Science.

[2]  C. Peters,et al.  Bubble-point pressures of the binary system carbon dioxide+linalool , 2001 .

[3]  Olav Bolland,et al.  High-temperature membranes in power generation with CO2 capture , 2004 .

[4]  Joan F. Brennecke,et al.  Solubilities and Thermodynamic Properties of Gases in the Ionic Liquid 1-n-Butyl-3-methylimidazolium Hexafluorophosphate , 2002 .

[5]  Hajime Matsumoto,et al.  Structure and properties of new ionic liquids based on alkyl- and alkenyltrifluoroborates. , 2005, Chemphyschem : a European journal of chemical physics and physical chemistry.

[6]  Q. Gan,et al.  An Experimental Study of Gas Transport and Separation Properties of Ionic Liquids Supported on Nanofiltration Membranes , 2006 .

[7]  Marek Kosmulski,et al.  Thermal stability of low temperature ionic liquids revisited , 2004 .

[8]  Paul J Dyson,et al.  Carbon monoxide solubility in ionic liquids: determination, prediction and relevance to hydroformylation. , 2004, Chemical communications.

[9]  E. Castner,et al.  Why are viscosities lower for ionic liquids with -CH2Si(CH3)3 vs -CH2C(CH3)3 substitutions on the imidazolium cations? , 2005, The journal of physical chemistry. B.

[10]  D. Armstrong,et al.  High-stability ionic liquids. A new class of stationary phases for gas chromatography. , 2003, Analytical chemistry.

[11]  Zheng Zhou,et al.  SO2 gas separation using supported ionic liquid membranes. , 2007, The journal of physical chemistry. B.

[12]  Mark B. Shiflett,et al.  Hydrogen purification using room-temperature ionic liquids , 2007 .

[13]  Brian J. Briscoe,et al.  Combining ionic liquids and supercritical fluids: in situ ATR-IR study of CO2 dissolved in two ionic liquids at high pressures , 2000 .

[14]  Paul J Dyson,et al.  Determination of hydrogen concentration in ionic liquids and the effect (or lack of) on rates of hydrogenation. , 2003, Chemical communications.

[15]  J. Brennecke,et al.  High-Pressure Phase Behavior of Carbon Dioxide with Imidazolium-Based Ionic Liquids , 2004 .

[16]  C. Peters,et al.  Solubility of carbon dioxide in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide , 2007 .

[17]  Hideto Matsuyama,et al.  CO2 separation facilitated by task-specific ionic liquids using a supported liquid membrane , 2008 .

[18]  D. Armstrong,et al.  Using geminal dicationic ionic liquids as solvents for high-temperature organic reactions. , 2005, Organic letters.

[19]  J. Esperança,et al.  Thermophysical and thermodynamic properties of ionic liquids over an extended pressure range : [bmim][NTf2] and [hmim][NTf2] , 2005 .

[20]  Joan F. Brennecke,et al.  High-Pressure Phase Behavior of Ionic Liquid/CO2 Systems , 2001 .

[21]  R. Noble,et al.  Regular Solution Theory and CO2 Gas Solubility in Room-Temperature Ionic Liquids , 2004 .

[22]  J. Brennecke,et al.  Improving carbon dioxide solubility in ionic liquids. , 2007, The journal of physical chemistry. B.

[23]  E. Karakatsani,et al.  Modeling of the carbon dioxide solubility in imidazolium-based ionic liquids with the tPC-PSAFT equation of state. , 2006, The journal of physical chemistry. B.

[24]  Joan F. Brennecke,et al.  Thermophysical Properties of Imidazolium-Based Ionic Liquids , 2004 .

[25]  Robert Quinn,et al.  New facilitated transport membranes for the separation of carbon dioxide from hydrogen and methane , 1995 .

[26]  R. Scott,et al.  Static properties of solutions. Van der Waals and related models for hydrocarbon mixtures , 1970 .

[27]  C. Chiappe,et al.  Ionic liquids: solvent properties and organic reactivity , 2005 .

[28]  Edward J Maginn,et al.  Measurement of SO2 solubility in ionic liquids. , 2006, The journal of physical chemistry. B.

[29]  Jung Min Lee,et al.  The removal of acid gases from crude natural gas by using novel supported liquid membranes , 2006 .

[30]  Poovathinthodiyil Raveendran,et al.  Exploring CO2-Philicity: Effects of Stepwise Fluorination , 2003 .

[31]  H. Ngo,et al.  Thermal properties of imidazolium ionic liquids , 2000 .

[32]  J. Brennecke,et al.  Why Is CO2 so soluble in imidazolium-based ionic liquids? , 2004, Journal of the American Chemical Society.

[33]  Y. Kameda,et al.  Solution structures of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid saturated with CO2: Experimental evidence of specific anion-CO2 interaction. , 2005, The journal of physical chemistry. B.

[34]  G. W. Meindersma,et al.  Solvent properties of functionalized ionic liquids for CO2 absorption , 2007 .

[35]  R. Quinn,et al.  Hydrogen sulfide separation from gas streams using salt hydrate chemical absorbents and immobilized liquid membranes , 2002 .

[36]  Cor J. Peters,et al.  High-pressure phase behavior of systems with ionic liquids: II. The binary system carbon dioxide+1-ethyl-3-methylimidazolium hexafluorophosphate , 2004 .

[37]  Sheng Dai,et al.  Low-Pressure Solubility of Carbon Dioxide in Room-Temperature Ionic Liquids Measured with a Quartz Crystal Microbalance , 2004 .

[38]  Collin R. Becker,et al.  Low Pressure Hydrocarbon Solubility in Room Temperature Ionic Liquids Containing Imidazolium Rings Interpreted Using Regular Solution Theory , 2005 .

[39]  Robin D. Rogers,et al.  Characterization and comparison of hydrophilic and hydrophobic room temperature ionic liquids incorporating the imidazolium cation , 2001 .

[40]  Paul H. Maupin,et al.  Flammability, thermal stability, and phase change characteristics of several trialkylimidazolium salts , 2003 .

[41]  Sheng Dai,et al.  Examination of the Potential of Ionic Liquids for Gas Separations , 2005 .