Modeling of polycyclic aromatic hydrocarbon SLE in aromatic solvents (original) (raw)
Related papers
Prediction of polycyclic aromatic hydrocarbon solubilities in benzene
Asia-pacific Journal of Chemical Engineering, 2007
Solubilities of polycyclic aromatic hydrocarbon (PAH) solutes; naphthalene, fluorene, acenaphthene, fluoranthene, anthracene, phenanthrene, pyrene, chrysene and triphenylene in benzene are predicted using UNIFAC, modified UNIFAC (Dortmund), and combination of Flory-Huggins and Scatchard-Hildebrand (FH-SH) methods. Applicability of the R-UNIFAC method to the binary PAHs in benzene systems is studied. Exponent R of the R-UNIFAC method is used in the modified UNIFAC (Dortmund) model to get a new expression for combinatorial activity coefficient. It is shown that the group contribution models using exponent R in combinatorial part of the equation perform much better than the original ones but none of the models considered satisfactorily predicts solid-liquid equilibria (SLE) of all PAHs studied (FH-SH model gives a prediction error of 98.08% for chrysene + benzene system). It is also shown that accounting the heat capacity change on melting terms makes considerable difference with ideal solubility in the case of higher melting PAHs in benzene. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.
Fluid Phase Equilibria, 2002
The Abraham general solvation model is used to predict the saturation solubility of crystalline non-electrolyte solutes in organic solvents. The derived equations take the form of 2 are the measures of the solute's hydrogen-bond acidity and hydrogen-bond basicity, π H 2 denotes the solute's dipolarity/polarizability descriptor, and L 16 is the solute's gas phase dimensionless Ostwald partition coefficient into hexadecane at 298 K. The remaining symbols in the above expressions are known coefficients, which have been determined previously for a large number of gas/solvent and water/solvent systems. Computations show that the Abraham general solvation model predicts the observed solubility behavior of pyrene, acenaphthene and fluoranthene to within an average absolute deviation of about +45%.
The solubility of anthracene and p-terphenyl in subcritical ethanol and water mixtures were measured using a static analytical equilibrium method between 393 and 473 K, and at 50 and 150 bar. Temperature and ethanol composition in the subcritical solvent mixtures were found to have significant effects on the solubility of polycyclic aromatic hydrocarbons (PAHs). The effect of pressure on solubility is negligible when the range of pressure considered is relatively small. An empirical model was proposed in the present study to correlate the solubility of PAHs to temperature and ethanol mole fraction. UNIQUAC, O-UNIFAC and M-UNIFAC models were compared, with the UNIQUAC model found to be in good agreement with experimental data.
Fluid Phase Equilibria, 2015
This study compares the capabilities of predictive equation of State/Gibbs free energy (EoS/G E) models to provide an accurate description of the solid-liquid phase equilibrium (SLE) of solid polycyclic aromatic hydrocarbons (PAHs) in sub-critical water (SBCW). The linear combination of Vidal and Michelsen (LCVM) mixing rule and the modified Huron-Vidal second order mixing rule (MHV2), in conjunction with the Peng-Robinson equation of state (PR-EoS), were used to predict the solubility of PAHs in SBCW, as a function of temperature. We compared the solubility predictions obtained from these EoS/G E models and estimated solubility based on UNIFAC activity coefficient models previously reported in the literature. Our results indicate that all the models provide reasonably good prediction of PAH solubilities, with the PR-LCVM model yielding the most accurate predictions. Further, an analysis of the temperature dependence of the solubility of PAHs in SBCW, shows a significant rise in solubility over and above a specific temperature range. We also examined the partial molar excess entropy, enthalpy and Gibbs energy of selected PAHs and discussed the thermodynamic driving forces responsible for the solubility of PAHs in SBCW.
Solubility and solubility modelling of polycyclic aromatic hydrocarbons in subcritical water
A static analytical equilibrium method was used to measure the binary and ternary solubilities of anthracene and p-terphenyl in subcritical water between 393 K and 473 K, and at 50 bar and 150 bar. Temperature was found to have the most significant effect on the solubility of polycyclic aromatic hydrocarbons (PAHs) in subcritical water. The effect of pressure, and the combined effect of temperature and pressure on solubility were found to be insignificant, particularly when the range of pressure considered is relatively small. The solubilities of PAHs were found to be governed primarily by sublimation pressure, and only secondarily by the dielectric constant of water. The Peng-Robinson equation of state was used to correlate the aqueous solubilities of PAHs at subcritical conditions, with good agreement between experimental and calculated values obtained for binary systems. HIGHLIGHTS Solubilities of PAHs in subcritical water increased exponentially with temperature. Temperature and solutes sublimation pressure govern solid solute solubility. The effect of the dielectric constant on solubility is secondary. The effects of pressure and density on solubility are insignificant. Peng-Robinson equation of state provides good correlation with experimental data.
The Open Thermodynamics Journal, 2011
The ability of two thermodynamic approaches to predict the solubility of solid compounds in hot pressurized water is studied and compared. The Regular Solution Theory, based on the solubility parameter concept, and UNIFACbased models were applied to calculate the solute activity coefficient and then, solubility predictions were compared with experimental data reported in the literature. The analysis was carried out considering polycyclic aromatic hydrocarbons as model substances, i.e. substances which contain only the aromatic AC and ACH groups, and for which reliable pure physical properties such as melting point, fusion enthalpy and molar volume are available in the literature. The solubility values predicted with the UNIFAC-based models were considerably better than those obtained with the solubility parameter approach. Particularly, the modified Dortmund UNIFAC model presented an appropriate functionality of solubility with temperature, and the extension of this model to other type of aromatic compounds also provided a satisfactory prediction of solubility data.
Thermodynamic Modeling of the Aqueous Solubility of PAHs
Industrial & Engineering Chemistry Research, 2009
Polycyclic aromatic hydrocarbons (PAHs) are a family of compounds characterized by having two or more condensed aromatic rings. They are important environmental contaminants associated with oil spills and the incomplete combustion of organic materials. Different models are available in the literature for estimating the aqueous solubilities of organic compounds, but the most accurate are frequently based on the correlation of experimental data, which hampers their use as predictive tools. In this work, the cubic-plus-association equation of state (CPA EoS) is shown to be an accurate model for describing the aqueous solubilities of several solid PAHs in wide temperature and pressure ranges. The results obtained are in very close agreement with the literature data, even when the model is used in a totally predictive scheme. Following previous results on the aqueous solubilities of other organic pollutants, the use of the CPA EoS for describing the aqueous solubilities of organic pollutants such as polycyclic aromatic hydrocarbons is suggested.
International Journal of Pharmaceutics, 1992
A remarkable improvement of the predictions of the solubility, qJB, of a solute B in a solvent S is achieved by the theory of the mobile order of Huyskens. In this theory, the hydrophobic effect of the associated solvents like alcohols against inert substances is no longer considered as a result from a change in the energy of the molecular interactions, but as a decrease of the entropy due to temporary correlated displacements of two or more hydroxylic groups of solvent molecules. Such correlated displacements create a kind of mobile order. Quantitatively, the hydrophobic effect reduces In ~B by an amount of rs@sVB/V s. A direct consequence of this effect is that an increase in the ratio VB/V s of the molar volumes, which in non-H-bonded solvents is favourable for the solubility, becomes unfavourable in alcohols. For polycyclic aromatic hydrocarbons, the prediction of the solubilities in apolar, polar and associated solvents by the mobile order theory necessitates the knowledge of a single parameter only which can be deduced from one experimental solubility.
Modeling of Multicomponent Nonaqueous Phase Liquids Containing Polycyclic Aromatic Hydrocarbons
1999
Multicomponent nonaqueous phase liquid (NAPL) contaminants that are mixtures of polycyclic aromatic hydrocarbons (PAHs) are examined using UNIFAC. The NAPL phase activity coefficients for constituent compounds of four different coal tar materials are estimated. The group contribution approach is adapted to describe representative molecular structures of the uncharacterized fractions of the tar materials, determined from average molecular weights and nonparametric regressions of the functional group parameters against molecular weight. The molecular structure characterization of the tars elucidates the similar chemistry of the materials from different sites, despite their different chemical compositions. Nearly ideal behavior is predicted for most tar constituents, with the majority of activity coefficients in the range of 0.9 to 1.1. These results provide a firm theoretical basis for an assumption of NAPL-phase ideality for many tar constituents. The robustness of this conclusion is...
Journal of Solution Chemistry, 1988
The solubilities of anthracene, acridine, xanthene, thioxanthene, carbazole, dibenzofuran, and dibenzothiophene have been experimentally determined in benzene, cyclohexane, thiophene, and pyridine from ambient temperature to approximately 440 K. The results have been correlated using the classical equation for solid-liquid solubility to obtain the experimental activity coefficient of the solute in the solvent. These experimental activity coefficients have been regressed, using three common solution models, to find the binary interaction parameters needed in those models. The solubilities of biphenyl, dibenzofuran, and dibenzothiophene have been ex-perimentaUy determined in five binary mixtures of the solvents. The experimental activity coefficients have been found and compared to the values predicted by the four solution models, using the binary interaction parameters obtained from the solubilities in the pure solvents and solventsolvent binary interaction parameters obtained from literature vaporliquid equilibria data. The effect of substituting various heteroatoms into the ring structure has been discussed.