Maria Toikka

Vapor-liquid equilibria in systems with esterification reaction

The article presents a review of phase equilibrium data for four-component systems involving ester synthesis and hydrolysis reactions (acid-alcohol-ester-water) systems. A brief characteristic of the experimental and calculated data is given.

Splitting of the liquid solution and the compositions of liquid phases in the water-n-propanol-n-propyl acetate system at 293.15, 303.15, and 313.15 K

New experimental data on solubility and liquid-liquid phase equilibrium in a water-n-propanol-n-propyl acetate system under polythermal conditions are presented. The results of modeling the liquid-liquid equilibrium using the UNIFAC model are given.

Solubility in the system constituted by acetic acid, n-propanol, water, and n-propyl acetate

Experimental data on the solubility in the system constituted by acetic acid, n-propanol, water, and n-propyl acetate at 313.15 K are presented. The position of the critical curve for the liquid-liquid equilibrium, including that of the critical points on the chemical equilibrium surface, is discussed.

Solubility and critical phenomena in reactive liquid–liquid systems

The goal of this work is to consider solubility phenomena in reactive fluid mixtures with liquid-phase splitting. One of the main tasks is to analyze peculiarities of liquid–liquid (LL) systems with equilibrium and nonequilibrium chemical reaction. The special aim is to consider the critical states in these systems. The reactive liquid–liquid equilibrium (LLE) is treated on the base of phase rule. The topology of diagrams of reactive LLE is discussed for some types of binary and ternary systems. Examples are presented of a possible transformation of phase diagrams caused by the shifting of chemical equilibrium and by changes in the shape of the binodal. The transformations resulting in the reactive critical phase formation are considered. Quaternary mixtures are also discussed with the use of experimental data on the solubility in the system with n-propyl acetate synthesis reaction. The mutual crossing of the chemical equilibrium surface and binodal in the composition tetrahedron leads to the origin of the area of simultaneous chemical and LLE with two critical points (reactive critical phases). The shape of the curve of simultaneous chemical and phase equilibrium is also presented in the square of transformed composition variables.

Experimental study of chemical equilibrium and vapor-liquid equilibrium calculation for chemical-equilibrium states of the n-propanol-acetic acid-n-propyl acetate-water system

Chemical equilibrium data for the n-propanol-acetic acid-n-propyl acetate-water system at 303.15 K are presented. The results of UNIFAC-based modeling of the vapor-liquid equilibrium in the system at 303.15 and 313.15 K are reported.

Phase and chemical equilibria in multicomponent fluid systems with a chemical reaction

Studies of the phase and chemical equilibria in the systems with chemical reaction cover a wide range of problems related to both experimental determination of physicochemical characteristics of these systems and various aspects of thermodynamic analysis of the phase and chemical processes occurring there. The main goal of this review consists in systematization and analysis of available experimental data concerning the vapour–liquid and liquid–liquid equilibria in multicomponent systems where chemical reactions occur. The studies considered here have been mainly published in recent years, and they include rather detailed data on physicochemical properties, phase transitions and chemical processes in fluid systems, i.e., the data which are essential for thermodynamic analysis. Available approaches to the thermodynamic analysis of heterogeneous systems with chemical reactions are also discussed. Particular attention is paid to the studies of the simultaneous phase and chemical equilibria. We hope that this review could be useful both for fundamental studies of heterogeneous reactive systems and for solving applied problems on the design of combined reactive and mass-transfer processes. The bibliography includes 79 references.

Peculiarities of phase diagrams of reactive liquid–liquid systems

The goal of this work is to consider some peculiarities of heterogeneous systems with chemical interactions. The main task is to analyze the features of liquid–liquid (LL) phase diagrams of the systems with equilibrium and nonequilibrium chemical reaction in solution. The consideration of topology of these phase diagrams should include additional elements, such as stoichiometric lines, chemical equilibrium (CE), and isoaffinity manifolds (i.e., curves, surfaces, or hypersurfaces of constant affinity). The thermodynamic conditions of mutual disposition of LL tie-lines, isoaffinity, and stoichiometric lines in ternary system are presented in the paper. Quaternary mixtures are discussed with the use of our experimental data on the solubility in the systems with ethyl acetate and n-propyl acetate synthesis reactions. The binodal and CE surfaces in these systems are presented. The opportunity of simultaneous LL and CE is discussed. The special aim is to consider the critical surfaces in these systems: the examples are presented on the basis of our experimental data.

Chemical equilibrium and liquid-phase splitting in acetic acid + n -propanol + n -propyl acetate + water system at 293.15 and 353.15 K

The paper presents new experimental data on the chemical equilibrium in the system n-propanol + acetic acid + n-propyl acetate + water at 293.15 and 353.15 K, and the data on liquid–liquid equilibrium at 353.15 K. Based on the experimental and literature data, the possibilities that chemical equilibrium exists in a homogeneous or heterogeneous region of compositions has been analyzed. The temperature shift of chemical and phase equilibria and the values of the thermodynamic constants of chemical equilibrium are discussed.

Chemical equilibrium in a heterogeneous fluid phase system: thermodynamic regularities and topology of phase diagrams

Singularities of the systems with simultaneous phase and chemical equilibria were examined. The thermodynamic regularities were revealed and topology of phase diagrams was presented for multicomponent heterogeneous systems including two or several equilibrium liquid phases (solution layering). The thermodynamic conditions for displacement of phase and chemical equilibrium are considered.

Chemical equilibrium of esterification in AcOH-EtOH-H2O-EtOAc system at 293.15 K

New experimental data on the chemical equilibrium of esterification in an acetic acid-ethanol-water-ethyl acetate system at 293.15 K and atmospheric pressure are presented.