Izvestiya of Saratov University.
ISSN 1816-9775 (Print)
ISSN 2541-8971 (Online)


Phase behavior and solubility of components of the binary butyric acid – polyethylene glycol-1500 system

A critical review of the literature on the methods of concentration and extraction of biobutyric acid from fermentation solutions has been carried out. The best results of these processes are achieved by combining extraction with salting. It is proposed to use polyethylene glycols with diff erent molecular weights as non-fl ammable and environmentally friendly extractants.


A technique of laboratory  synthesis  of potassium formate has  been developed. Phase equlibria in mixtures  of the components  of the binary  system potassium formate - water in the range from -70 to +170°C were investigated by  the visual-polythermal method. For the first time the phase diagram of the specified system has  been con­ structed and the coordinates  of an eutectic  point has  been estab­ lished. The formation of a crystalline hydrate КНСООИ.бНгО incon­ gruous  melting at -9.2°C was  found in this  system.

Study of the Stable Tetrahedron LiF-KF-KCl-K2WO4 of the Quinary Reciprocal System Li,K||F,Cl,WO4

The stable tetrahedron LiF-KF-KCl-K2WO4 of the quinary reciprocal system Li,K||F,Cl,WO4 was studied by differential thermal analysis, and the characteristics of eutectic and peritectic were determined.

Phase Diagram of the Potassium Thiocyanate – Water Binary System

The phase diagram of the potassium thiocyanate–water binary system was studied by the visual polythermal method and by the method of time–temperature curves over а temperature range – 35–180 оС. There is an eutectic equilibrium at –32.6 оС in the system; the solid phases of this equilibrium are ice and individual potassium thiocyanate. The composition of the liquid phase of the eutectic state was determined.

Phase Equilibria in the Twocomponent System n-nonadecan – Cyclododecane

Method of low-temperature differential thermal analysis using a differential scanning calorimeter of heat flow was first studied system n-nonadecane – cyclododecane. The studied systems are of the eutectic type. Alloy of eutectic composition contains 37,0 wt % of cyclododecane and melts at a temperature of 20.4 °C.

Research of Phase Equilibriums in a System of Dibasic Organic Acids: Azelaic, Glutaric and Sebacic

Presented first the results of the research of phase equilibria of threecomponent system azelaic acid – glutaric acid – sebacic acid by used the microcalorimeter heat flow. Identified eutectic composition containing azelaic acid – 33,0 wt %, glutaric acid – 54,0 wt %, sebacic acid – 13,0 wt %. The melting temperature of the alloy eutectic composition in the three-component system is 70,5 °C, the specific enthalpy of melting is 82 ± 10 J./g.

Quasi-binary Section Ag2SnS3-Sb2S3

Silver thiostannates and chalcostannates are widely used as promising functional materials which have semiconductor, thermoelectric, and photoelectric properties. The goal of this research is to study the Ag2SnS3-Sb2S3 phase diagram and determine the boundaries of solid solutions based on both components. Alloys were investigated using methods of physicochemical analysis. Based on the results of the study, a condition diagram of the Ag2SnS3-Sb2S3 system was constructed.

Density Calculation for Mixture Melts of LiF + NaF

Salt mixtures are used as molten electrolytes of chemical current sources, solvent melts of inorganic substances, heat storing compositions, fluxes for welding and soldering. Modern coolants include alkali metals and their halogenides. Lithium-containing thermofors have a special place. Density is one of the important properties of the melts used. The paper presents the analytical description of the density for the mixture melts of LiF + NaF of various compositions in the temperature range of 1130 ... 1320° K.

Phase diagram of the ?-alanine – water binary system

The phase diagram of the ?-alanine–water binary system was studied using the visual polythermal method and the method of time–temperature curves in а temperature range of -20–90°С. There is a eutectic equilibrium at -18.3°С in the system; the solid phases of this equilibrium are ice and individual ?-alanine. For the first time, the composition of the liquid phase of the eutectic state was determined.