A molecular simulation-based method for the estimation of activity coefficients for alkane solutions

Kontogeorgis, Georgios M.; Voutsas, Epaminondas; Tassios, Dimitrios P.

doi:10.1016/0009-2509(95)00400-9

Cited by 10 publications

(9 citation statements)

References 18 publications

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“…These data are comparable to the literature values for polyisobutylene (PIB) at 323.2 K: 4.56 for PIB(53 000)/cyclohexane17b and 5.90 PIB(53 000)/benzene 17c. Recently it was stated17a that the infinite dilution solvent weight‐fraction‐based activity coefficients, Ω 2pred ∞ , of a polyolefin could be assumed to be constant (4.39), independent of the system, the polymer molecular weight and temperature. This is valid for polymers like PE and PIB with normal and cycloalkanes 17a.…”

Section: Resultssupporting

confidence: 89%

“…The values of the polymer activity coefficients, presented in Table 8 as ln γ 1exp ∞ , are very small and range from −62 to −111. Values of the experimental solvent activity coefficients, γ 2exp ∞ , are comparable with solutions of other polymers, for example, 0.0287 for iPBu‐1/ n ‐hexadecane and 0.0262 for iPBu‐1/cyclohexane, whilst values of 0.0882 and 0.0095 are given for polyethylene(PE: 7400)/ n ‐dodecane17a and PE(35 000)/cyclohexane, respectively 17a. The experimental solvent weight‐fraction activity coefficients at 298.15 K, Ω 2exp ∞ , presented in Table 8 are, for example, 5.83 for iPBu‐1/cyclohexane and 9.55 for iPBu‐1/benzene.…”

Section: Resultssupporting

confidence: 58%

“…Recently it was stated17a that the infinite dilution solvent weight‐fraction‐based activity coefficients, Ω 2pred ∞ , of a polyolefin could be assumed to be constant (4.39), independent of the system, the polymer molecular weight and temperature. This is valid for polymers like PE and PIB with normal and cycloalkanes 17a. Our values range from 2.37 ( n ‐hexadecane) to 6.13 (cyclopentane).…”

Section: Resultsmentioning

confidence: 99%

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Phase Relationships and Thermodynamic Interactions of Isotactic Poly(1‐butene) and Organic Solvent Systems

Domańska¹,

Kozłowska²

2004

Chemistry A European J

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Isotactic crystalline low-molecular-weight poly(1-butene), iPBu-1, was synthesised by using a metallocene catalyst. The molecular weight was determined by GPC. The chemical structure of iPBu-1 was verified by using high-temperature (13)C NMR spectroscopy and the thermal properties by differential scanning calorimetry (DSC). The (solid+liquid) equilibria, SLE, of iPBu-1 with different hydrocarbons (n-hexadecane, 1-heptene, 1-heptyne, cyclopentane, cyclohexane, cycloheptane, cyclooctane, benzene and propylbenzene) were studied by a dynamic method. By performing these experiments over a large concentration range, the temperature-mole fraction phase diagrams of the polymer-solvent systems could be constructed. From these diagrams it was found that iPBu-1 had the highest solubility in small-ring cycloalkanes and the lowest in n-hexadecane, 1-heptyne and benzene in the mole fraction range measured. The excess Gibbs energy models were used to describe the nonideal behaviour of the liquid phase and to estimate the solubility of iPBu-1 in the whole mole fraction range. Activity coefficients at infinite dilution of polymer and solvent were determined from the solubility measurements and were predicted by using the UNIFAC FV model and molecular Monte Carlo simulations.

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Section: Resultssupporting

confidence: 89%

Section: Resultssupporting

confidence: 58%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Phase Relationships and Thermodynamic Interactions of Isotactic Poly(1‐butene) and Organic Solvent Systems

Domańska¹,

Kozłowska²

2004

Chemistry A European J

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“…(f) whether the model is in relative agreement with recent molecular simulation studies for model alkane systems and their interpretation by Kontogeorgis et al …”

Section: Activity Coefficient Models and Database For Slesupporting

confidence: 70%

Assessment of Activity Coefficient Models for Predicting Solid−Liquid Equilibria of Asymmetric Binary Alkane Systems

Polyzou

Vlamos

Dimakos

et al. 1998

Ind. Eng. Chem. Res.

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Hydrocarbon fluids play an important role in today's society, being essential components of oil and fuels. Phase equilibria knowledge of such mixtures is important in designing equipment and processes. Among the least studied equilibriums is that between solid and liquid phases (SLE) which is required in, e.g., wax formation studies. Still, a number of models have been proposed for estimating the activity coefficient but are rarely investigated against SLE data. In this study, a number of "well-established" and "up-to-date sophisticated" activity coefficient models are tested for their capability in predicting solid-liquid equilibria of alkane systems. A large database covering 63 alkane/alkane systems for which SLE data are available is considered. The models include several of the popular approaches proposed during the past 30 years covering the gap of a comprehensive literature review. The capabilities and limitations of the models are discussed and those that provide successful predictions are recommended at various levels of accuracy and complexity.

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“…A theoretical justification for these very low γ pol values was provided recently by Kontogeorgis et al (1996) using a molecular-simulation-based method for the estimation of activity coefficients for athermal polymersolvent mixtures. Their results were compared with the predictions of various activity coefficient models, and it was concluded that the FV models yield much better agreement with the molecular-simulation-based calculations for the polymer activity coefficient over the classical UNIFAC-type models.…”

Section: Resultsmentioning

confidence: 99%

Prediction of Ternary Liquid−Liquid Equilibria in Polymer−Solvent−Solvent Systems

Pappa

Kontogeorgis

Tassios

1997

Ind. Eng. Chem. Res.

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The performance of the entropic free-volume (FV) activity coefficient model and the Holten-Andersen et al. equation of state (EOS) in predicting the liquid-liquid equilibrium (LLE) for solutions involving one polymer and two solvents is examined. Both models are purely predictive since only the structures of the compounds involved and, in the case of the entropic FV model, the molar volumes are required. The necessary interaction parameters for both models are obtained from vapor-liquid equilibrium (VLE) data for mixtures of low molecular weight compounds. The entropic FV model qualitatively predicts the ternary LLE phase envelope for all the systems studied, while for some of them the predictions can be considered quantitative as well. The Holten-Andersen et al. EOS provides quite satisfactory results for some of the systems, while it fails for others. In addition, due to the UNIFAC parameter table employed, the entropic FV model is of wider applicability compared to the Holten-Andersen et al. EOS.

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A molecular simulation-based method for the estimation of activity coefficients for alkane solutions

Cited by 10 publications

References 18 publications

Phase Relationships and Thermodynamic Interactions of Isotactic Poly(1‐butene) and Organic Solvent Systems

Phase Relationships and Thermodynamic Interactions of Isotactic Poly(1‐butene) and Organic Solvent Systems

Assessment of Activity Coefficient Models for Predicting Solid−Liquid Equilibria of Asymmetric Binary Alkane Systems

Prediction of Ternary Liquid−Liquid Equilibria in Polymer−Solvent−Solvent Systems

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