Thermodynamic Analysis of the Wilson Model Using Partial Excess Functions

An approach to thermodynamic analysis of models of liquid solutions is developed. The approach is based on studying local characteristics of the concentration dependences of the partial excess molar functions. The applicability region is established, and constraints on the parameters of the Wilson equation are found.     

Transformation of diagrams of pseudoazeotropic mixtures

Some aspects of the transformation of diagrams of pseudoazeotropic mixtures are considered in the framework of the bifurcation theory. The results of the consideration are of fundamental importance for the development, implementation, and analysis of extractive distillation of mixtures with one nonvolatile (or low-volatile) component serving as an extractive agent.Translated from Teoreticheskie Osnovy Khimicheskoi Tekhnologii, Vol. 39, No. 2, 2005, pp. 192–198.Original Russian Text Copyright © 2005 by Serafimov, Frolkova, Tatsievskaya.     

Thermodynamic Analysis of the NRTL Model Using the Concentration Dependences of Excess Functions

Thermodynamic analysis of models of liquid solutions is carried out on the basis of the concentration dependences of excess functions. Using the energy balance plane, the applicability region of the nonrandom two-liquid (NRTL) equation is determined and constraints on the equation parameters are imposed.     

Flowsheet Synthesis Strategy for Irreversible Zeotropic Distillation

A strategy is suggested for the synthesis of the set of distillation flowsheets involving complex columns. The strategy is based on the transformation of flowsheets consisting of simple columns.     

Algebraic Sum of the Indices of Singular Points for Complexes of Various Dimensionalities

New equations for the algebraic sum of the indices of singular points are suggested for complexes of various dimensionalities.     

New forms of the azeotropic relationships for two-dimensional concentration complexes

The equations for the sum of Poincaré indices of the singular points in the tie-line vector field are written in new forms for various two-dimensional complexes. The equations are applied to systems at phase and chemical equilibria.     

Manifestation of ideality in nonideal ternary mixtures

The article deals with diagrams of three-component two-phase nonideal systems with an ideal vapor phase. One-dimensional manifolds along which the liquid phase of the mixture behaves as an ideal system are considered.     

Calculation of the liquid — Vapor phase equilibrium of nonideal systems

Conclusions It has been found that approximations made to equilibrium data by means of Auslander's equation ensure high accuracy during calculation, but in some cases lead to a discontinuity in the functions so that significant errors are obtained.Equations have been derived which exclude these discontinuities and they have been used for compiling a program (on a Minsk-2 electronic computer) for treating experimental data on phase equilibrium in binary mixtures and on the dependence of the boiling point on composition for multicomponent mixtures.Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 2, pp. 41–44, February, 1969.     

Thermodynamic modeling of liquid crystal-nonmesogen systems in the approximation of the theory of regular solutions

Nematic (or smectic-nematic) liquid crystal-nonmesogen systems are investigated by thermal analysis methods. A method for predicting the T-x diagrams of these systems using a model of regular solutions is proposed. The method gives good agreement between the predicted and experimental data in determining the phase separation in a system and calculating solubility polytherms. Specific features of calculation of the solubility parameter of liquid-crystal compounds are considered.     

Substantiation of Azeotropic Relationships for Two-Dimensional Concentration Complexes

An azeotropic relationship is derived to interrelate the singular points of distillation (reactive distillation) in two-dimensional n-gonal concentration complexes.