(461b) Tunable Reversible Ionic Liquids for CO2 Capture

Regulation of CO₂ emissions is likely in
the near future.  The technology for CO₂ capture from large
point-source CO₂ generators, such as coal-fired power plants, needs
to be developed before CO₂ emission regulation is mandated. 
Effective CO₂ capture systems must produce pure CO₂
streams without becoming an overly parasitic burden to the energy production
process.  Monoethanol amine (MEA) and other
aqueous-based systems have a record of high CO₂ capture capacities
but also high regenerative energies resulting in an increased parasitic load to
the plant.  Our research uses tunable reversible ionic liquids (RevILs) as the CO₂ capture system.  Here,
we maintain the benefit of high CO₂ capture capacities through
chemisorptions of CO₂ without the water excesses resulting in the
possibility of a less parasitic regeneration of the absorption system.

The RevILs that will be discussed here are
one-component silylamines.  Before CO₂ capture they are silylamine molecular liquids.  Upon reaction with CO₂,
the ionic form of the silylamine is produced
reversibly. The silyl group was incorporated with a
reactive primary amine to form the RevILs with
reduced viscosities. The structure of these silylamines
can be tuned to examine and ultimately enhance the desired properties of the
absorption system.  The impact of these structure modifications on the
properties of the silylamines have been studied with
two objectives in mind.  The first objective is to establish an
understanding of what the structural modifications do to the overall behavior
of the RevILs, including CO₂ capture
capacity, energy of regeneration and viscosity.  Once these
structure-property relationships are developed, the second objective is to use
these structure-property relationships to design a commercially viable RevIL system.  Additional factors that are considered
in this second objective include ease of synthesis of the silylamine
and stability of the silylamine during CO₂
capture and release cycling.  Promising RevILs
identified will be compared to conventional CO₂ capture systems.