Dilute Solution Behavior of Two Cyclic Anhydrides

Wong, K. F.; Eckert, Charles A.

doi:10.1021/i160037a004

Cited by 34 publications

(23 citation statements)

References 7 publications

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“…This method showed that the induction forces in liquids were much larger than was previously recognized (Moore, 1972). His average error of 14.2% is reasonable since Schreiber and Eckert (1971) and Tassios (1971) have demonstrated that the use of y"s to generate parameters for entropic equations to fit binary or multicomponent data accurately at all concentrations is fairly insensitive to modest perturbations in each ym. A discussion of this may be found elsewhere .…”

Section: Introductionmentioning

confidence: 79%

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Prediction of limiting activity coefficients by a modified separation of cohesive energy density model and UNIFAC

Thomas¹,

Eckert²

1984

Ind. Eng. Chem. Proc. Des. Dev.

202

154

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A modified separation of cohesive energy density (MOSCED) model was developed to predict limiting activity coefficients (7"'s) using only pure component parameters. For 3357 y"s, an average error of 9.1 % was achieved with very few errors greater than 30%. The data included activity coefficients of both protic and aprotic (but nonaqueous) systems over wide temperature ranges. The results compared very well with the predictions of the leading predictive technique in the literature, the UNIFAC solution of groups approach (average error 20.5 %).

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Section: Introductionmentioning

confidence: 79%

“…The evaluation of 7-also allows for the accurate calculation of kinetic solvent effects with the Bronsted-Bjerrum relationship (Wong and Eckert, 1971;Eckert et al, 1974;Newman, 1977;. If PZS 1 yl-< -< P18 Y2 or p 2 8 1 w,-> ->then an azeotype exists at some finite concentration (neglecting vapor phase nonidealities).…”

Section: Acknowledgmentmentioning

confidence: 99%

Prediction of limiting activity coefficients by a modified separation of cohesive energy density model and UNIFAC

Thomas¹,

Eckert²

1984

Ind. Eng. Chem. Proc. Des. Dev.

202

154

View full text Add to dashboard Cite

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“…Alternatively, one may fit the data to any of the empirical expressions for the excess Gibbs energy, but the y x value obtained will depend strongly on the mathematical behavior of that particular expression used near infinite dilution (see for example Wong and Eckert, 1971). Such uncertainty is one reason that infinite dilution activity coefficients have been so little used in the past.…”

Section: Conclusion and Significancementioning

confidence: 99%

Measurement and application of limiting activity coefficients

et al. 1981

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Infinite dilution activity coefficients (y") in binary liquid mixtures are data of wide practical and theoretical applicability, but their extensive use has been hindered by the experimental limitations of classical vapor-liquid equilibrium techniques. Two new experimental methods for accurate y" determinations are presented. These techniques, both faster and more accurate than classical methods, are complementary, and their applicability to different types of binary systems is discussed. SCOPEThe modern design and modeling of fluid-phase separation equipment require an accurate mathematical representation of chemical activities in a multicomponent liquid mixture. Solution models now use binary data only to represent a multicomponent mixture, and have proven central to the rational design of distillation, absorption, extraction, stripping, or even crystallization units. Although many sets of binary data exist in the literature, the limiting factor in most multicomponent process designs is in the acquisition of valid binary data needed to determine parameters in the mathematical models. For most miscible organic systems, the existing data are in the form of classical VLE (vapor-liquid equilibria) measurements, which are intrinsically slow and difficult experiments. Further, the resulting data, even if accurate, do not contain the most useful information either for a basic understanding of solution behavior or for practical application.It is the purpose of the current study to demonstrate a different approach to gathering the data needed for studying the solution thermodynamics of binary liquid mixtures as well as for designing multicomponent separations. The advantages of using infinite dilution activity coefficients were first proposed over twenty years ago, and their use in design and scale-up has often been demonstrated. However, the actual measurement of such quantities by classical means-either from VLE or LLE data-is very imprecise, and until recently newer experimental methods have been limited in applicability. This work presents two complementary experimental methods for measuring limiting activity coefficients in a wide variety of organic systems. Since these methods are both easier to use and intrinsically more accurate than the classical techniques, the use of limiting activity coefficients presents useful, new experimental and analytical approaches. CONCLUSIONS AND SIGNIFICANCELimiting activity coefficient (7%) data are most effective both in the description of binary mixtures and in the scale-up to multi-component systems. The limiting activity coefficient characterizes the behavior of a single solute molecule completely surrounded by solvent. As such, it generally indicates a maximum nonideality and offers incisive information to the theorist, since the order-disorder effect disappears; it also offers economy of effort to the experimentalist, since this datum has wider applicability than a measurement at any other concentration.The major reason that yx methods have been little used lies in the dif...

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“…A method for the prediction of Henry's constants in pure nonpolar and polar solvents, involving conversion of available Henry's constant values to symmetric infinite dilution activity coefficients and a modified UNIFAC model also extended to include freevolume effects, is presented in this paper. No (Tassios, 1969(Tassios, , 1971Wong and Eckert, 1971) where P, is the critical pressure of solute i and Tri is the solute reduced temperature.…”

Section: Introductionmentioning

confidence: 99%

Modified UNIFAC model for the prediction of Henry's constants

Antunes¹,

Tassios²

1983

Ind. Eng. Chem. Proc. Des. Dev.

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A group-contribution model for the correlation and prediction of Henry's constants In single solvents is presented.The model Involves a one-parameter per gas/solvent group pair UNIFAC expression extended to Incorporate free volume effects. The model Is applied to three gases, CH4, N2, and 02, In alkane solvents and In water. Good results, including a successful description of the temperature dependency of the Henry's constants, are obtained with typical accuracy of ±10%.

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Dilute Solution Behavior of Two Cyclic Anhydrides

Cited by 34 publications

References 7 publications

Prediction of limiting activity coefficients by a modified separation of cohesive energy density model and UNIFAC

Prediction of limiting activity coefficients by a modified separation of cohesive energy density model and UNIFAC

Measurement and application of limiting activity coefficients

Modified UNIFAC model for the prediction of Henry's constants

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