Prediction of the Solubility of Cholesterol and its Esters in Supercritical Carbon Dioxide (original) (raw)
Related papers
2007
In this work, the cholesterol concentration in the supercritical (SC) CO 2 , under working conditions, is calculated by implementing the modified Peng Robinson equation of state (EoS) combined with the Van Der Waals mixing rules. It was shown that this model achieves good correlation of the cholesterol solubility in SC carbon dioxide with an adjustable parameter called binary interaction coefficient (k ij ) and gives new estimation of the cholesterol critical parameter. A comparison of the experimental data given in literature with the commonly used Peng-Robinson equation reveals a good agreement of the empirical correlation of k ij written as a function of the operating temperature.
Solubility of cholesterol in supercritical carbon dioxide
Industrial & Engineering Chemistry Research, 1991
Supercritical fluid (SCF) extraction offers a good alternative to the current methods of extraction that normally involve the use of organic solvents. To perform this technique it is very important to know the solubility of the drug in the supercritical fluid, usually carbon dioxide. Several set of solubility data of cholesterol in supercritical CO 2 have been reported in literature: however there is a considerable inconsistency in the experimental results. In this work, the solubility of cholesterol in supercritical carbon dioxide at 313, 323 and 333 K and at pressures between 110-170 bar has been determined. The experimental data obtained have been compared with literature data and correlated with the Peng Robinson and the PHSC equations of state.
Modeling the solubilities of fatty acids in supercritical carbon dioxide
Fluid Phase Equilibria, 2003
A thermodynamic model was developed for modeling the solubilities of fatty acids in supercritical carbon dioxide. The model combines the Peng-Robinson equation of state (EOS) with the two parameter van der Waal's mixing rules. The model is applied to predict the solubilities of various fatty acids. The two adjustable interaction parameters in the model are found to vary linearly with the chain length of the fatty acids. Thus this model can be used to predict the solubilities of various fatty acids in supercritical carbon dioxide.
Solubility of selected esters in supercritical carbon dioxide
The solubility of ethyl propionate, ethyl butyrate, and ethyl isovalerate in supercritical carbon dioxide was measured at temperature ranging from 308.15 to 333.15 K and pressure ranging from 85 to 195 bar. At the same temperature, the solubility of these compounds increases with pressure. The crossover pressure region was also observed in this study. The experimental data were correlated by the semi-empirical Chrastil equation and Peng Á/Robinson equation of state (EOS) using several mixing rules. The Peng Á/Robinson EOS gives better solubility prediction than the empirical Chrastil equation. #
AIChE Journal, 2010
Chrastil (1982) established that the solubility of a substance in a supercritical fluid can be correlated with the density of the pure supercritical gas. Recently, the solubility of supercritical fluids in different organic liquids was successfully correlated as a function solely of the supercritical fluid density, since we demonstrated that the supercritical fluid density also defines the solubility of the gas in the liquid phase. In this work, the solubility of supercritical carbon dioxide in high molecular weight substances, such as high molecular weight paraffins, alcohols, fatty acids, fatty acid methyl and ethyl esters, has been correlated and constants provided. More than 20 binary systems comprising around 1000 solubility data points were correlated, obtaining regression coefficients greater than 0.96 and confirming the goodness of the densitydependent equation previously reported.
Prediction of solubility of biomolecules in supercritical solvents
Chemical Engineering Science Journal, 2001
The supercritical uid extraction (SFE) is considered an appropriate alternative for separation of biomolecules from food and pharmaceutical products. A major diiculty in utilizing the SFE for biomolecules has been the diiculty in measurement and prediction of their solubilities in supercritical solvents at various pressures and temperatures for process optimization. Lack of data for intermolecular energy parameters and=or critical properties, acentric factors, and molar refractions limits us to the use of the simple equations of state for prediction of their solubilities in supercritical solvents. In this report, six diierent cubic equations of state are used to predict the solubility of cholesterol and ÿ-carotene, as two representative biomolecules, in supercritical uids. They are the van der Waals, Redlich–Kwong, Mohsen-Nia–Moddaress–Mansoori (MMM), Peng–Robinson (PR) and Patel–Teja and modiÿed PR equations. It is shown that the two-parameter MMM equation is more accurate than ÿve of the other equations and comparable to the modiÿed PR equation in predicting the solubility of cholesterol and ÿ-carotene in supercritical uids.
Modeling of the Solubility of Solid High-Molecular-Weight Organic Substances in Supercritical Fluids
2003
A method is proposed to calculate the solubility of solid high-molecular-weight substances in organic supercritical fluids on the basis of the Soave and Peng-Robinson equations of state. The mixing rules are modified taking into account the Gibbs energy of mixing calculated for a particular equation of state. The accuracy of calculation of the concentration of the substance dissolved in supercritical fluids is analyzed for different mixing rules. The modeling results are compared with observed data.