Химия

The construction of a phases tree of a ternary system with three binary compounds KCaCl3 , K2 BaCl4 , CaBaCl4 is given. The phase tree includes four secondary phase triangles CaCl2 –KCaCl3 –СаBaCl4 , CaBaCl4 –KCaCl3 –BaCl2 , KCaCl3 –BaCl2 –K2 BaCl4 and KCaCl3 –CaBaCl4 –KCl. These triangles are connected by three stable secants KCaCl3 –СаBaCl4 , KCaCl3 –BaCl2 , KCaCl3 –K2 BaCl4 . Crystallizing phases in stable and secant elements correspond to the simplex tops.

Industrial development leads to an increasing number of persistent and highly toxic organic compounds such as phenol and formaldehyde. Chemical oxidation processes (in particular, photooxidation) are widely used for water treatment and wastewater and groundwater treatment. As part of the work done, an assessment of the possibility of using photocatalysis for post-treatment of wastewater from phenol, formaldehyde, and their mixtures has been carried out.

The relevance of this study is due to the need to develop methods for the extraction and quantitative determination of higher carboxylic acids in fi sh. In this work, we propose a simple, inexpensive, and highly sensitive extraction-photometric technique for the selective determination of the total content of fatty acids.

The synthesis of colloidal quantum dots of mercury selenide using mercury oxide as a precursor is proposed. The proposed method is characterized by the use of a less toxic component in the reaction mixture - mercury oxide. The transmission electron microscopy method established an average diameter of 5–6 nm and the shape of quantum dots. A histogram of the size distribution of synthesized nanoparticles is presented. An important property of the synthesized nanoparticles is the crystal structure established by X-ray diff raction analysis.

 A search and analysis has been carried out of English-language 2005–2020 scientifi c literature devoted to methods of obtaining branched (co)polymers of acrylamide, acrylic acid and (met)acrylates in order to obtain novel materials with valuable properties. It has been found that modern methods of controlled radical polymerization are mainly used for this purpose, namely, atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization (RAFT) and group transfer polymerization (GTP).

Reactions of 4-oxobutanoic acids as well as their cyclic analogues 3H-furan-2-ones with 1,3-binucleophilic reagent (2-aminophenyl) methanol lead to the formation of 1-R-5H-benzo[d]pyrrolo[2,1-b][1,3]oxazines and 3a-R-2,3,3a-trihydro-5H-benzo[d]pyrrolo[2,1-b][1,3]oxazin1-ones, respectively. Quantum-chemical calculations of the Fukui reactivity indices and local hardness have substantiated the mechanisms of the reactions carried out.

The sorption properties of some sands selected in the coastal zones of economically important, but at the same time ecologically oppressed territories of Vietnam are considered. The purpose of the research is to assess the absorption capacity of sands in relation to emulsifi ed petroleum products, to identify their ecological role in typical situations of spillage of small amounts of toxic substances. It is shown that the sorption qualities of the sands depend on the location of the sands, their geochemical and granulometric heterogeneity.