Critical properties of mixtures of alkanes from perturbation theory

MacDowell, Luis G.; Vega, Carlos; López-Rodríguez, A.

doi:10.1063/1.479598

Cited by 10 publications

(7 citation statements)

References 56 publications

(37 reference statements)

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“…New developments related to the formalism of Wertheim include the work of Vega and MacDowell, in which solid phases of hard-sphere chain molecules are considered, and a study of the vapor−liquid interface and surface tension of associating and chain fluids determined using a local density functional theory (DFT) that reduces to the SAFT-HS Helmholtz free energy in the bulk limit. , Several authors have also applied the SAFT equation of state to study other thermodynamic properties such as excess functions. − …”

Section: Introductionmentioning

confidence: 99%

Theoretical Examination of the Global Fluid Phase Behavior and Critical Phenomena in Carbon Dioxide +n-Alkane Binary Mixtures

2002

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The phase behavior of carbon dioxide + n-alkane binary mixtures is studied using the statistical associating fluid theory for potentials of variable attractive range. Extensive experimental data is available in the literature concerning the homologous series of carbon dioxide + n-alkane systems; these provide an excellent example of the continuity of fluid phase behavior in binary mixtures. Continuous transitions in the types of phase behavior are observed as the molecular weight of the n-alkane is increased. In our work, the carbon dioxide and n-alkane molecules are treated as attractive spherical segments tangentially bonded together. The attractive interactions are included as square-well potentials of depth and range λ. The pure component parameters of carbon dioxide are obtained by fitting to experimental vapor pressure and saturated liquid density data from the triple to the critical point, and the optimized molecular parameters of n-alkanes are taken from a set of transferable parameters previously presented Jackson, Phys. Chem. Chem. Phys. 1999, 1, 2057]. The optimized conformal molecular parameters (segment size and dispersive energy) are rescaled in order to give the best description of the experimental critical points. The critical lines and critical end-points, which determine the types of phase behavior, are predicted by the SAFT-VR approach in very good agreement with experimental data. This is particularly gratifying as the unlike dispersion interaction and range of the potential between carbon dioxide and alkane segments are obtained from a single mixture (CO 2 + n-tridecane) and then transferred to the other systems.

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Section: Introductionmentioning

confidence: 99%

Theoretical Examination of the Global Fluid Phase Behavior and Critical Phenomena in Carbon Dioxide +n-Alkane Binary Mixtures

2002

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“…The results have been interpreted using the SAFT−VR equation of state. , This theory can correctly predict the excess thermodynamic properties of these kinds of mixtures. MacDowell et al have recently calculated the excess properties of binary mixtures of n -alkanes using a modified perturbation theory, based on the Wertheim's first-order perturbation theory. Using a reasonable set of parameters, they are able to yield a qualitative correct description of the main trends of excess volumes and excess Gibbs energies of n -alkane mixtures.…”

Section: Introductionmentioning

confidence: 99%

Excess Thermodynamic Properties of Chainlike Mixtures. 1. Predictions from the Soft−SAFT Equation of State and Molecular Simulation

Blas

2000

J. Phys. Chem. B

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Monte Carlo simulation and theory are used to calculate excess thermodynamic properties of binary mixtures of Lennard-Jones chains. Chainlike molecules are formed by Lennard-Jones spherical sites that are tangentially bonded. This molecular model accounts explictly for the most important microscopic features of real chainlike molecules, such as n-alkanes: repulsive and attractive forces between chemical groups and the connectivity of segments to make up the chain. A version of the statistical associating fluid theory, the so-called Soft-SAFT equation of state, is used to check the theory's ability to predict this kind of property. Predictions from the theory are directly compared to NPT Monte Carlo simulation results obtained in the present work. The influence of segment size, dispersive energy, and chain length on excess properties is studied using simulation and theory, and results are analyzed and discussed. The equation of state is then used to predict the general trends of some excess thermodynamic properties of real n-alkane binary mixtures, such as excess volumes and heats. In particular, the temperature and chain-length dependence of these properties is studied. The Soft-SAFT theory is found to be able to correctly describe the most important features of excess thermodynamic properties of n-alkane models.

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“…Vega and collaborators 47,48 have probably proposed the first model in the literature able to provide a nearly quantitative description of V E (but considering also H E ) of mixtures of n-alkanes. In the first paper the authors developed a perturbation theory, based on Wertheim ideas, and in the second one they refined the model to make it possible to predict the V E and H E of n-alkanes.…”

Section: Molecular Modelsmentioning

confidence: 99%

CHAPTER 16. SAFT and Molecular Simulation Techniques: Application to Determination of Volumetric Excess Properties

Blas¹,

Piñeiro²

2014

Volume Properties

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Critical properties of mixtures of alkanes from perturbation theory

Cited by 10 publications

References 56 publications

Theoretical Examination of the Global Fluid Phase Behavior and Critical Phenomena in Carbon Dioxide +n-Alkane Binary Mixtures

Theoretical Examination of the Global Fluid Phase Behavior and Critical Phenomena in Carbon Dioxide +n-Alkane Binary Mixtures

Excess Thermodynamic Properties of Chainlike Mixtures. 1. Predictions from the Soft−SAFT Equation of State and Molecular Simulation

CHAPTER 16. SAFT and Molecular Simulation Techniques: Application to Determination of Volumetric Excess Properties

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