Prediction of the thermodynamic properties of complex polyatomic hydrogen bonding fluids

Ghonasgi, D.; Pérez, V.; Chapman, Walter G.

doi:10.1007/bf01438856

Cited by 3 publications

(11 citation statements)

References 25 publications

(26 reference statements)

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“…3 we see that intramolecular association is favored at low temperatures ͑or high association energies͒. In our previous paper 20 we developed an equation of state for ring molecules. Ring molecules have a compressibility factor less than that of monomer chain molecules with the same number of segments but greater than that for intermolecularly bonded dimers.…”

Section: Resultsmentioning

confidence: 89%

“…20 It was shown that the form of the Helmholtz free energy could be derived by considering the low density limit. 20 This is based, in part, on the observation by Andersen that the form of the combinatorial terms in cluster expansions of an associated fluid is the same regardless of the density. 24 Thus the form of the expression for the Helmholtz free energy can be easily determined at low density.…”

Section: Theorymentioning

confidence: 99%

“…To determine the fraction of molecules not bonded intramolecularly we use the theory developed in our previous paper 20 where we considered intramolecular association alone. This time imagine that the equilibrium distribution of intermolecular bonds have already formed; the molecules which are intermolecularly bonded are not available for intramolecular association.…”

Section: Theorymentioning

confidence: 99%

“…A drawback of Wertheim's theory is that it does not include intramolecular association and therefore is unable to predict the unusual phase behavior observed in some associating polymer systems. [1][2][3] Recently 20 we developed a new accurate theory for intramolecular association in fluids of hard chain molecules in the absence of intermolecular association. This theory was extended to produce an accurate equation of state for ring molecules.…”

Section: Introductionmentioning

confidence: 99%

“…This theory was extended to produce an accurate equation of state for ring molecules. 20 In this paper we consider the competition between inter-and intramolecular association and develop an accurate theory for the thermodynamic properties of this fluid. We consider a fluid of hard chain flexible molecules with one association site on each of the terminal spheres as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Competition between intermolecular and intramolecular association in flexible hard chain molecules

Ghonasgi

Chapman

1995

The Journal of Chemical Physics

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A perturbation density functional theory for the competition between inter and intramolecular association J. Chem. Phys. 136, 154103 (2012); 10.1063/1.3703015Mean field theory for the intermolecular and intramolecular conformational transitions of a single flexible polyelectrolyte chain A new theory to explain the competition between inter-and intramolecular association in flexible hard chain molecules is presented. The theory has been tested through comparisons with Metropolis Monte Carlo simulation results. For intermolecular association we use Wertheim's theory which has been shown to be accurate for intermolecular association in flexible associating hard chain molecules. For intramolecular association we use a theory we developed for intramolecular association in the absence of intermolecular association. These two theories are combined to develop a theory for the competition between inter-and intramolecular association. The new theory is in good agreement with simulation results and is able to predict some salient features of associating chain molecules. The theory predicts that intermolecular association becomes more important at high densities and that intramolecular association dominates at low density and low temperatures. In addition, theory and simulation show a minimum in the compressibility factor when plotted against the association energy at low density. This minimum is due to the presence of intramolecular association and is not observed for intermolecularly associating fluids.

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Section: Resultsmentioning

confidence: 89%

Section: Theorymentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Competition between intermolecular and intramolecular association in flexible hard chain molecules

Ghonasgi

Chapman

1995

The Journal of Chemical Physics

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Correlation and Prediction of Water Content in Alkanes Using a Molecular Theory

Emborsky

Cox

Chapman

2011

Ind. Eng. Chem. Res.

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We present a predictive model for the saturated water concentration in n-alkanes based on a theoretical equation of state for the hydrocarbon rich phase and a water equation of state for the aqueous phase. By considering a polar or associating component at low concentration in a nonpolar solvent, we can neglect polar or hydrogen bonding interactions in the hydrocarbon rich phase, thus reducing the number of fitted parameters. The approach allows us to determine the intrinsic pure component equation of state parameters independent of polar and associating interactions. As an example, the nonpolar, non-associating equation of state parameters for water are determined by fitting water solubility data in liquid hydrocarbons (carbon numbers (CN) = 4À13, 16) at ambient conditions. Using the PC-SAFT equation of state, a predictive model for the solubility of water in n-alkanes is produced. Comparisons of the model are presented with binary mixture experimental data for methane to decane across a wide range of conditions. Excellent qualitative and good quantitative agreement is exhibited without fitting a binary interaction parameter. The model is then extrapolated to predict water solubility in n-alkanes as a function of temperature, pressure, and carbon number for conditions where experimental data is of questionable validity or unavailable. Implications on the potential model used in molecular simulations are also discussed.

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Equation of State of Hydrogen-Bonded Polymer Solutions. Poly(propylene glycol) + n-Hexane and Poly(propylene glycol) + Ethanol

et al. 1997

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We have measured the equation of state surface over the whole composition range for the mixtures poly(propylene glycol) + ethanol and poly(propylene glycol) + n-hexane up to 40 MPa. The excess volume for the system with ethanol is negative, decreasing in magnitude with increasing pressure. For the system with n-hexane, the excess volume becomes positive at high pressure and presents a complex shape with two changes in curvature along the composition axis. The p-F-T data obey a superposition principle that makes it possible to build a master curve once the p-F-T surface is known at a given pressure. The master curve depends on a single system-dependent parameter. The results have been analyzed with a lattice fluid model. The inclusion of hydrogen bond contributions in the model does not improve the prediction of the p-F-T data for the system with n-hexane, while it makes a significant contribution in the system with ethanol, especially in ethanol-rich mixtures.

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Prediction of the thermodynamic properties of complex polyatomic hydrogen bonding fluids

Cited by 3 publications

References 25 publications

Competition between intermolecular and intramolecular association in flexible hard chain molecules

Competition between intermolecular and intramolecular association in flexible hard chain molecules

Correlation and Prediction of Water Content in Alkanes Using a Molecular Theory

Equation of State of Hydrogen-Bonded Polymer Solutions. Poly(propylene glycol) + n-Hexane and Poly(propylene glycol) + Ethanol

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