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Allyl-Containing Ionic Liquid Solvents for CO2 Capture

National Energy Technology Laboratory

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Technology Marketing Summary

Research is active on the patent pending technology titled,“Sulfur Tolerant Ionic Liquid Solvent for Pre-combustion Carbon Capture.” This invention is available for licensing and/or further collaborative research from U.S. Department of Energy’s National Energy Technology Laboratory.


Low temperature, pre-combustion carbon dioxide (CO2) capture is typically accomplished using physical solvents such as Solexol™. This is due to the high partial pressure of CO2 in the flue gas stream which is sufficient to dissolve significant amounts of CO2 into the solvent without the need for additional chemical reactions. Regeneration of the solvent and release of CO2 can be accomplished with increased temperature and/or pressure reduction. However, there is a need to create solvents that are tolerant to sulfur, and water, which can operate at higher temperatures. In addition, the solvents need to have low viscosity, high CO2 solubility, and excellent CO2/hydrogen (H2) selectivity.

This invention describes the use of allyl group containing ionic liquid solvents (ILs) for pre-combustion CO2 capture. The inclusion of allyl groups into ionic liquids structure produces ILs with lower viscosity and better CO2 solubility than their alkyl counterpart. In addition, these materials tend to be tolerant to sulfur and water. The ionic nature of these materials renders them with low vapor pressure, high thermal stability and high CO2/H2 selectivity.

  • ILs produced using this method are sulfur and water tolerant
  • ILs display lower viscosity and enhanced CO2 solubility
  • Superior CO2 and H2 selectivity
Applications and Industries
  • Pre-combustion CO2 capture
  • H2 purification
  • Natural gas sweetening
  • Allyl-containing ILs can be used as a transport medium for supported liquid membranes since the allyl bond can be used to polymerize ILs and make membrane polymers
More Information

U.S. Patent No. 9,975,080 issued on May 22, 2018 titled “Sulfer Tolerant Hydrophobic Ionic Liquid Solvent.”

Inventors: David Luebke, Hunaid Nulwala, Robert Thompson, Nicolas Siefert, Fan Shi, and Brian Kail

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 9,975,080
Sulfur tolerant hydrophobic ionic liquid solvent
Exemplary embodiments relate to methods for removal of CO.sub.2 and other acid gases from gaseous fuels prior to combustion. Exemplary methods may be used for CO.sub.2 capture, H.sub.2 purification and natural gas sweetening. Exemplary methods use at least one ionic liquid that has excellent CO.sub.2 solubility, selectivity over hydrogen, low viscosity, and resistance to H.sub.2S.
Technology Status
Development StageAvailabilityPublishedLast Updated

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