Correlation of the Binary Interaction Factor for Polar Solutes Dissolved in Supercritical Carbon Dioxide (original) (raw)
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The Solubility of Organic Compounds in Supercritical CO2
Zeitschrift für Naturforschung A, 2005
A simple liquid solution model is proposed to describe the effect of solvent-solute interactions on the solubility of nonpolar and slightly polar substances in supercritical solvents. Treating the system as an ideal solution, the effect of pressure on the solubility is zero or nearly zero, as it is governed by the difference in molar volume of the pure supercooled liquid solute and the pure solid solute, and this may be nearly zero. Deviations from ideal behavior are given by activity coefficients of the Margules type with the interaction parameter w interpreted as interchange energy as in the lattice theory. The hypothesis is put forward that the interchange energy is of the same form as a function proposed by Liptay and others to describe the effect of the solvent on the wavelength of the absorption maximum of the solute dissolved in the solvent. The function consists of a radius of interaction a and a function g(ε ) of the dielectric constant ε of the solvent, treated as a contin...
Solubility of solid and liquid mixtures in supercritical carbon dioxide
Industrial & Engineering Chemistry Process Design and Development, 1985
Solubility data for mixtures of naphthalene wlth phenanthrene, phenol, and biphenyl in supercritical carbon dioxide were obtained. The equilibrium solubilities were measured in a semicontinuous flow apparatus. Experiments were conducted at 308 and 318 K isotherms, over a pressure range of 5 to 28 MPa. Selectivity of carbon dioxide to dissolve these heavy components preferentially is discussed as a function of pressure and extent of solubliity.
Using solute structure to predict solubility of organic molecules in supercritical carbon dioxide
The Journal of Supercritical Fluids, 2006
Predictions of critical parameters and the Pitzer factor for three different group contribution methods are compared and used in correlative predictions of virial coefficients. These virial coefficients are then used to determine the chemical potential of a solute in supercritical carbon dioxide as a function only of the solute structure. Experimental chemical potentials are determined from measured solubility data and compared to calculated chemical potentials by using both experimental vapour pressures and vapour pressures estimated from the solute structure by group contribution methods. The group contribution method of Marrero and Gani is shown to best reproduce experimental solubility data with an average absolute relative deviation of 10.4% ("exact" experimental input data only yields an accuracy of 10.7% for the molecules studied here). The obtained accuracy for several common organic pollutants (naphthalene, benzoic acid, anthracene, phenanthrene, naphthol-2 and pyrene) suggests that the method is applicable for predictions on previously unmeasured systems as long as the molecule has fewer than 20 non-hydrogenic atoms and is relatively rigid.
Representing solute solubility in supercritical carbon dioxide: A novel empirical model
Chemical Engineering Research and Design, 2015
In this paper, a new empirical model proposed for mathematical representation of solutes solubility in supercritical carbon dioxide. The accuracy of the proposed model is compared to previously published models in literature using experimental data of dyes and drugs collected from literature (more than 2400 data points). According to obtained results, the proposed model presents much more accurate estimation/prediction for in solubility. So, in order to accelerate the industrial processes, the proposed model can be employed and strongly recommended.
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.
Fluid Phase Equilibria, 2003
The ability to correlate and predict the solubility of solids in supercritical fluids is of the utmost importance for the design and the evaluation of supercritical processes. Previously, we have investigated the solubility of a pharmaceutically interesting solid compound in supercritical carbon dioxide, alone or mixed with cosolvents. In this work, these solubility data are correlated through several density-based semi-empirical models. These models have been either modified or extended to be applied to mixtures including a cosolvent. The validity of the resulting correlations is checked by using the solubility data of another pharmaceutical solid, naproxen.
The Journal of Supercritical Fluids, 2004
Temperature independent mixing rules in cubic equations of state (EoS) have been used to correlate the solubility of solids in supercritical carbon dioxide. The mixing rules of [Chem. Eng. Sci. 41 (5) (1986) 1303] who proposed a transformation of standard cubic equations of state so that the equations of state constants are really constants, have been evaluated and modified. The modification consists of introducing a volume interaction parameter that affects the solute contribution only as proposed by one of the authors [Ing. Quim. Spain 34 (394) (2002) 380], into the Peng-Robinson equation of state. Literature data for eight binary mixtures containing supercritical carbon dioxide and a solid solute were used for testing the proposed models. The systems studied were binary mixtures containing supercritical carbon dioxide with 2,3-dimethylnaphthalene, 2,6-dimethylnaphthalene, naphthalene, phenanthrene, anthracene, pyrene, benzoic acid and caffeine. The proposed model, in which the equation of state constants and the mixing rules are all temperature independent, correlates the solute concentration in the gas phase similar and better than models that use temperature dependent constants and temperature dependent mixing rules.
A Density-Dependent Solute Solubility Parameter for Correlating Solubilities in Supercritical Fluids
Industrial & Engineering Chemistry Research, 1998
A density-dependent solute solubility parameter has successfully correlated solubilities in supercritical fluids (SCFs). Fifteen solutes, including polar and nonpolar compounds, have been studied in up to four SCFs. A two-parameter, linear fit resulted in a median average absolute relative deviation (AARD) of 20%, ranging from 6.1% to 42%, for the 34 systems studied. A three-parameter power fit provided a median AARD of 12%, ranging from 2.3% to 38%.
Polar Attributes of Supercritical Carbon Dioxide
Accounts of Chemical Research, 2005
Supercritical carbon dioxide (scCO2) is increasingly promoted as an environmentally benign alternative to conventional organic solvents. The supercritical state bridges the gap between liquid and gaseous states by offering gaslike diffusion rates and liquidlike solvent densities, thereby enabling potential opportunities as a reaction and separation medium in chemical industry. Understanding the solvent behavior of liquid and scCO 2 is of critical importance to enable the design of CO2-philic molecular systems and to expand the use of these solvent systems to a wider range of chemical processes. Historically CO2 was treated as a nonpolar solvent, primarily because of its low dielectric constant and zero molecular dipole moment. CO2 has also been described as a quadrupolar solvent because of its significant quadrupole moment. Recent studies suggest that, as far as the microscopic solvent behavior of CO2 is concerned, CO2 has the potential to act as both a weak Lewis acid and Lewis base. Also, strong theoretical and experimental evidence indicates that CO2 can participate in conventional or nonconventional hydrogen-bonding interactions. All of these site-specific solute-solvent interactions are important to understand the fundamental nature of CO2 as a solvent. In this Account, we discuss these polar attributes of CO2 and their relation to solvation.