AOT reverse microemulsions in scCO2 — a further investigation

The solubility of riboflavin (RF), potassium ferricyanide (K3Fe(CN)6) and polar components from yeast extract (YX) in a sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) modified supercritical carbon dioxide (scCO2) system was investigated. The results from RF solubility studies indicate that the microemulsion phase formed by AOT contains a polar core with an effective static dielectric constant of 20±5. Although this core is not indicative of bulk water, the overall improvement in polarity from pure scCO2 is approximately a factor of 10. K3Fe(CN)6, a highly ionic compound, could not be solubilised into the modified supercritical fluid, indicating that the core was not sufficiently polar to dissolve highly ionic compounds. Finally, successful extraction of polar compounds from YX demonstrated the potential industrial applications of AOT-modified scCO2.