AOT reverse microemulsions in scCO(2) - 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) su lfosuccinate (AOT) modified supercritical carbon dioxide (scCO(2)) system w as investigated. The results from RF solubility studies indicate that the m icroemulsion phase formed by AOT contains a polar core with an effective st atic dielectric constant of 20 +/- 5. Although this core is not indicative of bulk water, the overall improvement in polarity from pure scCO(2) is app roximately a factor of 10. K3Fe(CN)(6), a highly ionic compound, could not be solubilised into the modified supercritical fluid, indicating that the c ore was not sufficiently polar to dissolve highly ionic compounds. Finally, successful extraction of polar compounds from YX demonstrated the potentia l industrial applications of AOT-modified scCO(2). (C) 2001 Elsevier Scienc e B.V. All rights reserved.