Химия

The paper presents a theoretical and experimental study of the three-component mutual system Na+ ,Sr2+||F- ,WO4 2-. In the theoretical part, geometric modeling of phase complex is carried out. The thermodynamic method, according to Hess’s law, confirmed the partition variant with three phase triangles NaF – SrF2 – SrWO4 , NaF – 2NaF•Na2 WO4 – SrWO4 , 2NaF•Na2 WO4 – SrWO4 – Na2 WO4 . In accordance with the chosen partition option, the simulation of the liquidus variants of the three-component mutual system Na+ ,Sr2+||F- ,WO4 2- has been carried out.

The use of inductively coupled plasma mass spectrometry for differentiation of natural and imitated caviar of various fish species: salmon, sturgeon, and particulate species has been proposed. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been used as tools for multivariate statistical analysis. The use of PCA and HCA have allowed effective visualisation of differences between caviar samples in terms of authenticity.

A luminescent method for determining glycine based on competitive complexation of Cu2+ ions with ciprofl oxacin and an amino acid is proposed. Formation of a Cu2+ complex with a fl uoroquinolone derivative is shown using spectrophotometry. The resulting complex does not have fl uorescent properties, unlike the ligand itself. In the presence of additives of complexing agent ions in a ciprofl oxacin solution, its fl uorescence is quenched.

Selection of parameters for the synthesis of precursors for NMC cathode materials is one of the prevailing factors that have a signifi cant impact on the chemical composition, bulk density, surface microstructure, electrochemical characteristics and service life of the resulting cathode materials. In this paper, we study the variation of the mixing rate, pH, concentration of the complexing agent, and the molar ratio of NH3 / sulphate solution concentrations.

Currently, the synthesis of oxygen-containing heterocyclic compounds containing a fused benzene ring system with a pyrone cycle, represented by 4-hydroxycoumarin (4-hydroxy-2H-chromen-2-one), is of great importance due to their broad spectrum of biological activity. We found it interesting to conduct reactions of 1,5-dicarbonyl compounds based on 4-hydroxycoumarin with N-nucleophiles, both from a fundamental point of view and from the perspective of the practical application of the resulting products.

The interaction of cationic halcogenpyrilocyanic dyes, 2,6-diphenil-4-(4-dimethylaminostyryl)pyrylium and -thapyrylium chlorides, with inorganic ions in aqueous solutions was studied. The spectrophotometric characteristics and stability constants of the resulting ion pairs were determined.

The work was aimed at establishing new correlations between some known energetic characteristics of several materials and their performance.