In this work, the solubility of ergosterol, which is a natural phytosterol exhibiting cholesterol-lowering properties and is of particular interest to the food and nutraceutical industries, in supercritical carbon dioxide was measured with a semi-flow type phase equilibrium apparatus. The solubility experiment was performed at pressures in the range of 120-240bar and at temperatures of 318.15, 323.15, and 333.15K, and the measured solubility ranged from 2.9?10-6 to 3.0?10-5. The high-pressure solubility data for each isotherm were correlated by the Schmitt-Reid and Giddings models with average absolute relative deviations (AARD) ranging from 4.1 to 9.7% and 2.2 to 5.5%, respectively. The Chrastil model and the M?ndez-Santiago and Teja model were also used to fit the entire data set yielding AARDs of 7.6% and 8.5%, respectively. Furthermore, the Peng-Robinson equation of state (EOS) using one-parameter and two-parameter van der Waals mixing rules was employed to fit the experimental solubility data with the latter giving a significantly smaller AARD of 6.4%. Retrograde behavior of the solute's solubility in the supercritical fluid was observed and was also predicted by the equation of state. ? 2012.
Relation:
Journal of the Taiwan Institute of Chemical Engineers,Vol.44,Issue1,P.19-26
