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Title: Equimolar CO(2) capture by imidazolium-based ionic liquids and superbase systems

Imidazolium-based ionic liquids continue to attract interest in many areas of chemistry because of their low melting points, relatively low viscosities, ease of synthesis, and good stabilities against oxidative and reductive conditions. However, they are not totally inert under many conditions due to the intrinsic acidity of hydrogen at the C-2 position in the imidazolium cation. In this work, this intrinsic acidity was exploited in combination with an organic superbase for the capture of CO{sub 2} under atmospheric pressure. During the absorption of CO{sub 2}, the imidazolium-based ionic liquid containing an equimolar superbase reacted with CO{sub 2} to form a liquid carboxylate salt so that the equimolar capture of CO{sub 2} with respect to the base was achieved. The effects of ionic liquid structures, types of organic superbases, absorption times, and reaction temperatures on the capture of CO{sub 2} were investigated. Our results show that this integrated ionic liquid-superbase system is capable of rapid and reversible capture of about 1 mol CO{sub 2} per mole of ionic liquid. Furthermore, the captured CO{sub 2} can be readily released by either heating or bubbling N{sub 2}, and recycled with little loss of its capture capability. This efficient and reversible catch-and-release process usingmore » the weak acidity of the C-2 proton in nonvolatile imidazolium-based ionic liquids provides a good alternative to the current CO{sub 2} capture methods that use volatile alkanols, amines, or water.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [3]
  1. ORNL
  2. Pacific Northwest National Laboratory (PNNL)
  3. Zhejiang University
Publication Date:
OSTI Identifier:
1044699
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Green Chemistry; Journal Volume: 12; Journal Issue: 11
Research Org:
Oak Ridge National Laboratory (ORNL)
Sponsoring Org:
SC USDOE - Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; ABSORPTION; AMINES; ATMOSPHERIC PRESSURE; CHEMISTRY; HEATING; HYDROGEN; MELTING POINTS; MOLTEN SALTS; PH VALUE; PROTONS; SYNTHESIS; WATER