Results 131 to 140 of about 351 (174)

Correlation of binary liquid-liquid equilibrium data over a wide temperature range using UNIQUAC and extended UNIQUAC models

Fluid Phase Equilibria, 1991
Abstract The temperature effect on mutual solubility data for 81 binary systems has been studied by means of UNIQUAC and extended UNIQUAC models. The energy parameters of the models are expressed by a quadratic function of temperature. Among the systems studied 61 systems have an upper critical point, 14 systems have a closed partial miscibility and ...
Isamu Nagata, Thomas Meyer, Jürgen Gmehling   +2 more
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A phase stability analysis of the combinatorial term of the UNIQUAC model

Chemical Engineering Science, 1999
The conditions for the onset of liquid-phase instability in the combinatorial contribution of UNIQUAC are discussed. A peculiar and non-physical aspect of this predicted instability is that it is independent of temperature. It is recognized that by renormalizing the r and q parameters, this type of phase transition can be prevented.
Charlles R.A. Abreu, Marcelo Castier, Frederico W. Tavares   +2 more
openaire   +1 more source

Modeling of heavy metal salt solubility using the extended UNIQUAC model

AIChE Journal, 2002
AbstractSolid–liquid equilibria in complex aqueous systems involving a heavy metal cation (Mn2+, Fe2+, Co2+, Ni2+, Cu2+, or Zn2+) and one or more ions for which Extended UNIQUAC parameters have been published previously are modeled using the Extended UNIQUAC model.
Maria C. Iliuta, Kaj Thomsen, Peter Rasmussen   +2 more
openaire   +1 more source

Comparison of UNIQUAC with related models for modelling vapour sorption in polar materials

Journal of Membrane Science, 1998
Abstract By a systematic investigation of solvent polymer systems of even greater complexity, this work analyses the relative performances of UNIQUAC and related models to account for sorption phenomena in polar elastomers (polyurethaneimides) with vapours of moderate to strong polarity (ether, ester, alcohol).
Anne Jonquières, Laurent Perrin, Stéphanie Arnold, Pierre Lochon   +3 more
openaire   +1 more source

Prediction of CO2 solubility in ionic liquids with QM and UNIQUAC models

Journal of Molecular Liquids, 2016
Abstract In recent years, ionic liquids shows their abilities in many processes, like enzymatic reactions, electrochemical applications, catalysis processes, or separation processes. In this work, CO2 solubility in Ionic liquids has been calculated based on two thermodynamic models, i.e., the UNIQUAC model and the quantum model, based on COSMO-RS ...
Amin Kamgar, Mohammad Reza Rahimpour
openaire   +1 more source

On the calculations of azeotropes from the NRTL and UNIQUAC models

Fluid Phase Equilibria, 1993
Abstract The local composition models of NRTL and UNIQUAC have been used in predicting of azeotropic data for binary and ternary liquid mixtures of various types. Activity coefficients have been calculated using the temperature dependent parameters of the models.
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Excess enthalpy surfaces for alkanol-alkane mixtures by the uniquac model

Thermochimica Acta, 1995
Abstract Temperature and composition dependences of excess enthalpy surfaces and composition fluctuations were calculated using the uniquac model and the Kirkwood-Buff theory of statistical mechanics for seven alkanol-alkane mixtures. Surfaces of partial molar excess enthalpies and enthalpy of dilution were also calculated.
Y. Demirel, E.Z. Hamad
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A new predictive UNIQUAC for modeling of wax formation in hydrocarbon fluids

Fluid Phase Equilibria, 2006
A new UNIQUAC based predictive local composition model is here compared against predictive Wilson and predictive modified UNIQUAC on their abilities to predict wax formation. For that purpose a very large database of phase equilibrium data of both synthetic and real hydrocarbon fluids, at both low and high pressures, will be used.
Coutinho, J., Mirante, Fatima, Pauly, Jérôme   +2 more
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A Modification of UNIQUAC Model for Electrolyte Solutions Based on the Local Composition Concept

Journal of Solution Chemistry, 2020
In the present study, a thermodynamic model is developed to predict the phase equilibrium of electrolyte solutions. In this model the Pitzer–Debye–Huckel equation was used to calculate the long-range contribution of the activity coefficient. To take into account the short-rang part of activity coefficient a new modified UNIQUAC-based model was ...
Hamid Bakhshi, Poorya Mobalegholeslam
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Calculations of thermodynamic derivative properties from the NRTL and UNIQUAC models

Thermochimica Acta, 1997
Abstract The local composition models NRTL and UNIQUAC with temperature-dependent parameters have been employed to calculate the surfaces of excess heat capacity, C E p , excess enthalpy, h E and thermodynamic factor, Γ for binary liquid mixtures. These thermodynamic properties represent the derivatives of the models with respect to temperature,
Demirel Y., Paksoy H.O.
openaire   +2 more sources