critical phenomena

Phase Equilibria and Component Solubility in the Binary System Water + Dipropylamine

Authors: Smotrov M. P., Umetchikov V. A., Danilina V. V., Cherkasov D. G.

Dipropylamine is one of the promising antisolvents for extractive salt crystallization, but its solubility in water and phase equilibria in its aqueous solutions over a wide temperature range has not been studied in detail until now. The review of the literature shows that the water-dipropylamine system is classified as a self-separating system with a lower critical solution temperature (LCST). We used the visual-polythermal method in a –25–90°C range to study phase equilibria in the binary system water-dipropylamine and to plot the phase diagram of the system.

Phase Equilibria in the Ternary System “Potassium Iodide – Water – Tert-Butyl Alcohol” within 5–30°C

Authors: Varlamova Т. М.

Studying of the influence of the salt nature and temperature on the liquid-liquid equilibrium in the ternary systems “salt – binary solvent” is topical for the development of the salting-in–salting- out theory. In addition, the ternary potassium iodide-water-alcohol systems are constituents of the quaternary iodine – potassium iodide – water – alcohol ones, studying of which is of practical interest in terms of determining the mixed solvent compositions with the highest iodine-dissolving power.

Topological Transformation of Phase Diagrams for Сut 1 of the Quaternary System Potassium Nitrate – Water – Pyridine – Butyric Аcid in 5–60оС

Authors: Cherkasov D. G., Chepurina Z. V., Kurskii V. F., Il’in K. K.

Phase equilibria and critical phenomena in component mixtures of the cut 1 of the quaternary system Potassium Nitrate – Water – Pyridine – Butyric Аcid whose constituent ternary liquid system had a closed binodal curve were studied by means of the visualpolythermal method within 5–60oC. The volumes of two monotectic states in the composition tetrahedron have been found to be in contact via critical tie lines with increasing temperature.

Phase Equilibria and Critical Phenomena in the Water–i-Butyric Acid Binary System

Authors: Smotrov M. P.

Phase equilibria and critical phenomena in the water-i-butyric acid binary system were studied by the visual polythermal method over the temperature range –10–30°C. The system is characterized by delamination with an upper critical solution temperature (UCST) equal 25.8°C. In the system at –1.8°C, these occurs a nonvariant monotectic equilibrium whose solid phase are ice crystals. The phase diagram of the system is plotted.