Oxygenated hydrocarbon ionic surfactants exhibit CO2 solubility.
Several oxygenated hydrocarbons, including acetylated sugars, poly(propylene glycol), and oligo(vinyl acetate), have been used to generate CO2-soluble ionic surfactants. Surfactants with vinyl acetate tails yielded the most promising results, exhibiting levels of CO2 solubility comparable to those associated with fluorinated ionic surfactants. For example, a sodium sulfate with single, oligomeric vinyl acetate (VAc) tails consisting of 10 VAc repeat units was 7 wt % soluble in CO2 at 25 degrees C and 48 MPa. Upon introduction of water to these systems, only surfactants with the oligomeric vinyl acetate tails exhibited spectroscopic evidence of a polar environment that was capable of solubilizing the methyl orange into the CO2-rich phase. For example, a single-phase solution of CO2, 0.15 wt % sodium bis(vinyl acetate)8 sulfosuccinate, and water, at water loading (W) values ranging from 10 to 40 at 25 degrees C and 34.5 MPa, exhibited a methyl orange peak at 423 nm. This result indicated that the core of a reverse micelle provided a microenvironment with a polarity similar to that of methanol. Quantum chemical calculations indicate that the acetylated sugars may be too hydrophilic to readily form reverse micelles, whereas the VAc-based surfactants appear to have the correct balance of hydrophilic and hydrophobic forces necessary to form reverse micelles.
Fan
Xin
X
Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
Potluri
Vijay K
VK
McLeod
M Chandler
MC
Wang
Yang
Y
Liu
Juncheng
J
Enick
Robert M
RM
Hamilton
Andrew D
AD
Roberts
Christopher B
CB
Johnson
J Karl
JK
Beckman
Eric J
EJ
D002245:Carbon Dioxide / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D012995:Solubility; D013501:Surface-Active Agents / Q000138:chemical synthesis / Q000737:chemistry*
D006838:Hydrocarbons; D013501:Surface-Active Agents; D002245:Carbon Dioxide; D010100:Oxygen