Results 131 to 140 of about 404 (171)

A Modified UNIQUAC Model That Includes Hydrogen Bonding

Industrial & Engineering Chemistry Research, 1995
Based on the association theory of Wertheim, a UNIQUAC association (UNIQUAC-A) model has been developed in which the hydrogen bond is treated as a strong interaction rather than as a chemical reaction. Compared with the original UNIQUAC model, the UNIQUAC-A model results in better correlations of binary vapor-liquid equilibrium data for self ...
Yuan-Hao Fu, Stanley I. Sandler, Hasan Orbey   +2 more
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A crossover‐UNIQUAC model for critical and noncritical LLE calculations

AIChE Journal, 2015
A new model, named the crossover‐UNIQUAC model, has been proposed based on the crossover procedure for predicting constant‐pressure liquid–liquid equilibria (LLE). In this manner, critical fluctuations were incorporated into the classical UNIQUAC equation. Coexistence curves were estimated for systems having a diverse range of asymmetries.
Parvaneh, Khalil, Haghbakhsh, Reza, Shariati, Alireza, Peters, Cor J.   +3 more
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Application of the UNIQUAC equation to regular solutions

Fluid Phase Equilibria, 1992
Abstract Soave, G., 1992. Application of the UNIQUAC equation to regular solutions. Fluid Phase Equilibria, 77: 133-137. It is possible to make the UNIQUAC equation tend to the Scatchard-Hildebrand equation when approaching ideal solution behaviour by taking q2/q1 = v2/v1 and τ12 = τ21.
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Effective uniquac equation in phase equilibrium calculation

Fluid Phase Equilibria, 1981
Abstract A new equation for the excess Gibbs energy similar to the UNIQUAC equation is presented. The equation is found to give better data reduction results for those binary systems where an alcohol is one of the components. Successful prediction of ternary vapor-liquid equilibria using only binary parameters is demonstrated.
Isamu Nagata, Kazuo Katoh
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Improvement of the UNIQUAC Combinatorial-Entropy Term by Adjusting the Standard Segment

Journal of Chemical & Engineering Data, 2011
A standard segment is used to determine the structural parameters r and q of the UNIQUAC combinatorial-entropy term. Generally, it is assumed that the choice of the standard segment and the influence of the absolute value of q are negligible. The standard segment area, however, does not cancel out in the model equation and, therefore, is a model ...
Bronneberg, Rob, Pfennig, Andreas
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Representation of solubilities of amino acids using the uniquac model for electrolytes

Chemical Engineering Science, 1994
Abstract A molecular thermodynamic framework for the representation of the solubilities of several binary systems, amino acids—water (nine systems) and peptides—water (five systems), has been developed and tested. The proposed model takes into account simultaneously the chemical and physical equilibrium.
Peres, António M., Macedo, Eugénia A.
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UNIQUAC model for wax solution with pour point depressant

Fluid Phase Equilibria, 2009
Abstract It had been shown that after adding pour point depressant (PPD), the diffraction line intensities of paraffin mixtures progressively decreased without any significant variation of the Bragg angle values. This phenomena is due to the structure of paraffin mixture is partly transformed from orthorhombic into hexagonal form.
W.H. Chen, X.D. Zhang, Z.C. Zhao, C.Y. Yin   +3 more
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Ternary liquid-liquid phase behavior by decorated-uniquac

Korean Journal of Chemical Engineering, 1996
To investigate the applicability of the decorated-UNIQUAC model for multicomponent multiphase liquid mixtures, equilibrium calculations were carried out for a variety of model ternary systems, and some typical predictions were introduced. The predicted phase behavior was less limited and more complicated than that of UNIQUAC without disagreement with ...
Kim, YC, Kim, JD Kim, Jong-Duk, Kim, H
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Analog calorimetry and UNIQUAC group contributions approaches to the miscibility of pvc with eva copolymers

Journal of Thermal Analysis and Calorimetry, 2002
The miscibility of blends of poly(vinyl-chloride) (PVC) with poly(ethylene-co-vinyl acetate) (EVA) was investigated through analog calorimetry and a group contribution procedure based on the UNIQUAC model. The group contribution parameters quantifying the pair interactions between the structural features of the above polymers were calculated from ...
BERNAZZANI, LUCA, C. Cardelli, CONTI, GIOVANNI, P. Gianni   +3 more
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Correlations in published values of UNIQUAC interaction parameters

Fluid Phase Equilibria, 1983
Abstract There is a high degree of correlation between interaction parameters in the UNIQUAC equations. The coefficients for 43 sets of data for binary liquid-vapor equilibrium for ethanol-water at various temperatures and pressures as published in Dechema Chemistry Data Series (1977) are correlated by the equation (Aij + c)(Aji + c) = 2000000 where ...
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