Химия

There were considered and analysed main scientific and pedagogical problems which were described in investigations of Professor Isaac Mustafin in Saratov State University in the fields of organic, analytical, physical, biological, caustibiolite's chemistry and of the history of science. Also there was given review of the works of different investigators of I.S. Mustafin's scientific inheritance.

Industrial metal-cement catalyst NKO-2-3, GTT, NTK-10-2 is investigated. Catalytic activity of metal-cement catalysts for flue gases neutralization under oxidation and reduction activation at 350°C is studied.

A lyotropic cubic LC phase stable in wide ranges of temperature (0–90°C) and dendrimer concentration (1.7–36.5 wt %) was detected in the binary system CCl₄ + an LC third-generation dendrimer with cyanobiphenyl mesogenic groups. A concentration phase transition from an isotropic solution to an LC state was observed by means of viscometry.

Phase equilibria and critical phenomena in the ternary system potassium nitrate – water – methyldiethylamine, where a constituent binary liquid system is characterized by phase separation with a lower critical solution temperature (LCST), were studied by means of the visual-polythermal method within 25–55°C.

A novel scheme of the isothermal phase diagram of the quaternary system salt + three solvents with three liquid-phase equilibrium (its ternary liquid subsystem to be characterized by a band-like delamination region) was deduced by means of the topological transformation method.

Complexation of the rare-earth elements (REE) La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb with o-phthalic acid was studied potentiometrically at 298 K and an ionic strength of 0.2 (KCl). Complex species MHA²⁻ and MA⁺, M being REE and A – C₆H₄O₄²⁻, were detected. The pH range and stability constants of the complexes were established.

The structure of complexes of lithium, sodium, and potassium cations with molecules of several aprotic solvents (diethyl carbonate, dimethyl sulfoxide, and dimethyl formamide) was studied by means of the density functional method. Changes in the geometry and electronic structure of the solvent molecules at their coordination with an alkaline metal ion are considered.

Optimal conditions for synthesis of 2,4-diphenyl-5-oxo-5,6,7,8-tetrahydrochromillium salts on the basis of triketones of 2-(1,3- diphenyl-3-oxopropyl)-cyclohexanedione-1,3 have been found. For the first time the ability of oxo-1,5-diketones with no substituent at C-1 of the side chain to form salts has been established.

In the traditional method of removing excess acid used to obtain the salt form of chitosan, not only a reaction with neutralizing bases proceeds, but also partial deprotonation of macrochains. Since charged amino groups are responsible for the biological activity of the aminopolysaccharide, it seems important to develop methods for optimizing the acid–base composition of a chitosan-containing system without proton elimination.