Abstract
In this work, we have investigated the influences of the extraction feed bed composition on ternary solubilities of mixed cholesteryl benzoate(CBE) and cholesteryl butyrate (CBU) in supercritical carbon dioxide at 318.15 K. Measurements undertaken demonstrate a mutual solubility decrease for both cholesteryl esters and the solubility decrease is found to be strongly dependent of the composition of the extraction equilibrium chamber. The ternary solubility data were correlated using the Peng-Robinson equation of state model along with one-parameter mixing rules. The Wilson equation was used in an attempt to calculate the solute activity coefficient in the solute matrices. The calculations show that the ternary fugacities of both solutes are dependent on the bed matrix composition and much lower than their binary ones, being in a very good consistence with the mutual solubility diminutions observed. (C) 2009 Elsevier B.V. All rights reserved.