Thermodynamic Properties of Liquid Mixtures: Aromatic-Saturated Hydrocarbon Systems

Funk, Edward W.; Prausnitz, J. M.

doi:10.1021/ie50729a004

Cited by 63 publications

(23 citation statements)

References 9 publications

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“…For these nine mixtures, the results of the MRST Equation (31) were in excellent agreement with the experimental data of Funk and Prausnitz (1970) who presented their results in the form of a Redlich-Kister correlation using fitted parameters which predicted the experimental aGPe with an average error of about 3%. However, it was observed that the original regular solution theory gave essentially the same results as the MRST.…”

Section: Resultssupporting

confidence: 79%

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A modification of regular solution theory to incorporate an improved approximation for pair distribution functions in mixtures

Gonsalves

Leland

1978

AIChE Journal

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The radial distribution functions for pairs in a fluid mixture can be closely approximated from known data on pair distribution functions for pure components evaluated at a mean density determined by a properly defined average of molecular interaction parameters in the mixtures. This approximation has been used to replace the assumption about structure in mixtures inherent in the traditional regular solution theory. The result is a modified regular solution theory which gives an improvement in predicting excess thermodynamic functions and activity coefficients in mixtures involving appreciable differences in molecular size and shape. This study was conducted to investigate the usefulness of some new theoretical knowledge about the structure of fluid mixtures. The term structure in mixtures of simple fluids means a description of the probability of finding the center of one molecule at various distances from the center of another and the probability that the molecules found at a given separation belong to various species among those present in the mixture.This new theoretical development was used to improve the description of structure inherent in the Hildebrand regular solution theory using solubility parameters. The simplicity of this theory has made it attractive for engineering computations, but, in its original form, it was quite limited in its range of applicability. bne of the early improvements in the theory was the incorporation of the Flory-Huggins equation for the entropy of mixing to replace the ideal solution entropy of mixing asaumed by the original theory.?his work is an attempt to make another improvement in this theory by improving one of the basic assumptions while retaining as much as possible its simplicity. The objective is to remove the unrealistic assumption in the original theory that the probability of a particular pair of molecules having a specified center-to-center separation distance in the mixture is independent of composition and is exactly the same as that of the pair in a pure component at the temperature and pressure of the mixture.The correct pair distribution function in a mixture of dissimilar molecules, however, is very much composition dependent, and the improvement here accounts for this dependence by means of an assumption called the mean density approximation. The effectiveness of this approximation is demonstrated in this paper by comparison of pair distribution functions in an ideal mixture of Lennard-Jones fluids calculated by this procedure with those obtained from computer simulations of this mixture.The new approximation was incorporated into the regular solution theory and tested by making excess free energy calculations in real binary mixtures with varying degrees of dissimilarity of molecular size and character. CONCLUSIONS AND SIGNIFICANCEThe results for the new modified regular solution theory (MRST) show in every case an improvement in calculated values of the excess Gibbs free energy and excess enthalpy of mixtures when the molecules in the mixture differ appr...

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Section: Resultssupporting

confidence: 79%

“…In Equation (23) U1' -U{ is evaluated at V i and T, whereas in Equation (24) U1* -U1 is evaluated at V1 and T. Using Equation (25), we get where m12 is the unlike pair interaction term introduced by Funk and Prausnitz ( 1970).…”

Section: Making a Taylor Series Expansion Aboutmentioning

confidence: 99%

A modification of regular solution theory to incorporate an improved approximation for pair distribution functions in mixtures

Gonsalves

Leland

1978

AIChE Journal

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“…The isothermal free energy change is given as JG1=\ V1dP=RTA lnf1 (8) where A and B indicate the ideal gas state and the hypothetical liquid state, respectively. Then the hypothetical liquid fugacity can be written as /***à">=/*«*>«p(-JL[°V*W) (9) where V^L is the hypothetical liquid volume obtained from The change of atomization mechanismat the edge of a rotating disk was studied based on theoretical consideration and various experimental data.…”

Section: Resultsmentioning

confidence: 99%

Application of Regular Solution Theory to Vapor-Liquid Equilibria of Cryogenic Fluids

Sagara

Yokobori

Saito

1974

J. Chem. Eng. Japan

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The regular solution theory was applied to predict the vapor-liquid equilibria of cryogenic fluids, such as argon, nitrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethylene, ethane and propane. Whenthe system temperature is sufficiently below the critical temperature of each component, the vapor-liquid equilibria were well predicted by using the liquid properties at the saturation line of pure component. When the system temperature is close to the critical temperature of light component, good results were obtained by adjusting the liquid volume of the light component only. This liquid volume was determined by fitting calculated vapor-liquid equilibrium relations to the experimental results and was generalized as a smoothed curve. This generalized curvewasalso useful in estimating the hypothetical liquid volume.Vapor-liquid equilibria involving a supercritical component were predictable by using the hypothetical liquid fugacity and the solubility parameter obtained based on the generalized curve for the adjusted liquid volume.

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“…Further modifications of the FloryHuggins theory have been presented and successfully applied to describe asphaltene precipitation. One example of such modifications is based on including a binary interaction parameter [108] that characterises the interaction between unlike molecules, as applied by Pazuki and Nikookar [109] and Mofidi and Edalat [110]; this interaction parameter is determined as a function of molecular weight [109,110]. Mohammadi et al [111] have combined the approach with chemical theory to account for asphaltene self-association resulting in n-mer aggregates.…”

Section: Lattice Fluid Theoriesmentioning

confidence: 99%

Thermodynamic modelling of asphaltene precipitation and related phenomena

Forte

Taylor

2015

Advances in Colloid and Interface Science

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Thermodynamic Properties of Liquid Mixtures: Aromatic-Saturated Hydrocarbon Systems

Cited by 63 publications

References 9 publications

A modification of regular solution theory to incorporate an improved approximation for pair distribution functions in mixtures

A modification of regular solution theory to incorporate an improved approximation for pair distribution functions in mixtures

Application of Regular Solution Theory to Vapor-Liquid Equilibria of Cryogenic Fluids

Thermodynamic modelling of asphaltene precipitation and related phenomena

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