Switching solvents and surfactants using CO2 at 1 atmosphere

I&EC 84

Philip G. Jessop, Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada, Charles A. Eckert, cae@gatech.edu, School of Chemical and Biomolecular Engineering and Specialty Separations Center, Georgia Institute of Technology, 311 Ferst Drive, NW, Atlanta, GA 30332-0100, and Charles L. Liotta, School of Chemistry and Biochemistry, Georgia Institute of Technology.
While elevated pressures of CO2 gas can be used to modify solvent properties by expansion, it is possible to modify the properties of some solvents with only atmospheric pressure CO2. 1 atm of gaseous CO2 causes certain low polarity liquids to change into more polar liquids (ionic liquids). The effect can be reversed by the application of N2. The different liquids, their polarities, and example applications will be described. Surfactants are widely used in the mining, energy and manufacturing industries to stabilize emulsions for a stage in the process, after which the emulsion is no longer required. Because breaking the emulsion is made more difficult by the presence of the surfactant, it would be preferable if the surfactant can be turned off. “Switchable surfactants" will be described which are “turned on” (become able to stabilize emulsions) by an atmosphere of CO2; when the CO2 is removed, the emulsion breaks.

 

Green Chemistry and Engineering with Gas Expanded Liquids and Near-Critical Media
8:00 AM-11:25 AM, Wednesday, August 22, 2007 Boston Park Plaza -- Clarendon Rm, Oral

Division of Industrial & Engineering Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007