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.

Evolution of Weakly Non-Linear Perturbations in Gas Suspension with Chemical Reaction

Dynamics of weak finite-amplitude perturbations in two-phase homogeneous medium (gas + solid particles) with nonequilibrium chemical reaction in gas is studied theoretically. Weakly non-linear model of plane perturbation evolution is substantiated by the instrumentality of asymptotic approach. The model takes into account wave-kinetic interaction and dissipation effects, including inter-phase heat and momentum transfer. Stability conditions for uniform state of the system are analyzed. Non-linear equation describing evolution of plane perturbations is derived under weak dispersion and dissipation effects. Solutions of evolution equation are obtained numerically in form of steady-state oscillations. Its parameters are determined by effect of nonlinearity and by relation between dissipative property of two-phase medium and given modeling characteristics of kinetics of reaction

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.