Home – Home – Jornals – Chemistry for Sustainable Development 2021 number 6

Dechlorination of the hydroxy derivatives of polychlorinated biphenyls in coal tar pitch has been carried out. It is shown that the heat treatment of polychlorinated biphenyl congener mixtures and hydroxy derivatives of polychlorobiphenyls in toluene-insoluble substances of coal tar pitch involves hydrodechlorination of chloroarenes and their hydroxy derivatives with hydrogen transfer from coal tar pitch compounds. The major products of these reactions are the products of condensation with coal tar pitch compounds, as well as congeners of polychlorinated biphenyls and hydroxyl derivatives of polychlorobiphenyls a smaller number of chlorine atoms.

The results of laboratory studies on the additional treatment of model wastewater from pharmaceutical production with the help of the combined effect of UV radiation and hydrogen peroxide are presented. Literature data on the existing purification technological schemes were analyzed, with the determination of their main advantages and disadvantages. Experimental results were obtained on the treatment of model solutions of acetylsalicylic acid, tetracycline and sulfadimezin after passing through three stages of purification: photooxidation, coagulation, and sorption. The values of chemical oxygen demand (COD) and concentration of active pharmaceutical ingredients (API) were determined. The combined action of photooxidation and hydrogen peroxide makes it possible to achieve purification efficiency up to 80 % for COD and up to 99 % for API. A technological scheme for the treatment of pharmaceutical wastewater is proposed.

Hematite nanoparticles (23-150 nm) were obtained and dispersed in a hydrocarbon medium. The introduction of hematite nanoparticles at a concentration of 0.02 to 0.30 mass % into the oil residue during thermolysis allows increasing the yield of gasoline and reducing the yield of resins. The role of hematite is explained by its ability to selectively sorb resins and asphaltenes on its surface.

Antiviral activity of extracts from 14 plant species of 12 genera of 9 botanical families in the transplanted culture of MDCK cells against influenza virus A/Aichi/2/68 (H3N2) (human) and A/chicken/Kurgan/05/2005 (H5N1) (birds) was investigated. Phytochemical characterisation of vegetal raw materials of these species for the content of certain groups of polyphenolic and terpenoid compounds was carried out. The effect of plant extracts on the influenza virus of each subtype was assessed relying on the value of the neutralization index. It was found that aqueous and ethanol extracts of the studied plant species exhibit different extents of activity against each of the influenza virus subtypes: from minimum to almost 100 % of virus-inhibiting values. Complete (100 %) inhibition, selectively for each of the two influenza virus subtypes, was found in the extracts of 6 plant species: three Persicaria species ( P. scabra, P. lapathifolia, P. hydropiper ), Comarum salesovianum (leaves and flowers), Dasiphora fruticosa and Hedysarum alpinum . They can be considered promising for further studies of antiviral activity against the human and bird influenza virus. A phytochemical assessment of the plant raw materials of the studied species showed that maximum amounts of flavonols (6.42 %), catechins (1.76 %), tannins (28.46 %) and carotenoids (70.4 %) were found in the raw materials of different plant species, extracts of which showed selective influenza activity of varying extent. Promising species can be recommended for more in-depth study, as basic, in order to develop phytopreparations of anti-influenza action against RNA-genomic viruses - human and bird influenza virus. At the same time, it is necessary to take into account the taxonomic position of the species, the type of extraction, as well as the part or organ of the plant taken for study.

This paper presents experimental data on the physicochemical properties of oxidized bitumen produced by the oil refinery plants OJSC TAIF-NK and OJSC Syzran Oil Refinery before and after aging in a thin film in the presence of the developed additive Adgezolin, as well as in the composition with polymer-bituminous binders obtained on the basis of these bitumens. The domestic adhesive additives BP-KSP, Adgezol-6 and imported additive Wetfix (Sweden) were used for comparison. The most significant change (∆ T ) in brittleness temperature (5.1 °С) was found in bitumen samples modified with 0.35 mass % Adgezol-6 and 0.5 mass % Wetfix additives, which does not correspond to the methodological document of the road construction industry (ODM 218.2.004-2006). In addition, the study of the qualitative properties of polymer-bitumen binders in comparison with the original bitumen shows that the addition of polymers to the studied bitumen has a positive effect on ∆ T of softening after heating; this indicator is within the state standard GOST (not more than 5 °C). The introduction of additives also improves the aging stability of the bitumen: introduction of Adgezolin additive in an amount of 0.8% causes a significant decrease in ∆ T of softening. Comparative analysis of the efficiency with respect to industrially developed domestic and foreign additives allows us to emphasize the high quality of modified bitumen based on Adgezolin additive. Malacometric indicators for evaluating the quality of bitumen modified with the developed Adgezolin additive characterize less severe aging of bitumen binders in comparison with the considered additives, which allows us to recommend it for industrial approval.

The work is devoted to the synthesis and study of porous carbon materials: thermally expanded graphite (TEG), carbon nanofibres, and activated carbon. The possibility of using them in electrochemical current sources, in particular, in supercapacitors, was investigated. The physicochemical properties of the obtained samples were studied by low-temperature nitrogen adsorption, cyclic voltammetry, and electron microscopy. The modification of carbon materials was carried out in three ways, and the effect of the modification on the values of specific capacitance and surface area was studied. It is revealed that the samples are characterized by the well developed porous structure: for initial materials, the maximum surface area was 759 m²/g, while for the composites obtained as a result of modification, it was 187 m²/g. It was shown that the highest specific capacitance was typical for the materials possessing micro- and mesoporous structure, with an average pore size of 3-5 nm. Modification of the surface of carbon materials with nickel led to a decrease in the specific surface area, an increase in the average pore diameter, and also, in some cases, to an increase in the specific capacitance. Among the materials with deposited nickel particles, the maximum specific capacity (116 F/g) was exhibited by a composite of 20 mass % NiО/80 mass % TEG. Treatment with nitric acid and mechanical activation led to an increase in the fraction of micropores in the samples and to an increase in the specific capacitance. The data obtained prove that the studied carbon materials are highly promising for electrochemical applications.

A series of previously unknown 1,3-dialkyl-4-nitro-1,2,3-triazolium salts with the substituents of different kinds (alkyl = Me, Et, n -Pr, i -Pr, n -Bu, s -Bu, i -Amyl) were synthesized by regioselective quaternization of N2- and N3-alkyl-4-nitro-1,2,3-triazoles with dialkyl sulphates in a high yield. These salts are gaining an ever-growing interest in the chemistry of energetically efficient materials, catalysts and ionic liquids. Among the two regioisomers, solely N3-substituted derivatives were found to be involved in the reaction with dialkyl sulphates. The products of N2-substitution do not enter quaternization, and this fact makes it possible to separate the mixtures of N2- and N3-isomers that exhibit close physicochemical characteristics limiting their separation by preparative techniques. The structures of the new 1,3-dialkyl-4-nitro-1,2,3-triazolium salts were proved by means of IR spectroscopy, ¹H and ¹³C NMR spectroscopy, as well as single-crystal X-ray diffraction and elemental analysis.

Quantitative chemical analysis of snow for the concentrations of water-soluble forms of Zn, Pb, Cd, Cu was carried out by means of stripping voltammetry in snow water sampled in 2019. The content of organic carbon in the sediments collected on the filter was determined using titrimetry. Calculation of liquid and solid melt runoff during the snow flood of 2019 was carried out relying on the results of chemical and analytical monitoring. Based on the previous chemical and analytical studies of the solid particles in snow cores for the content of the sorbed forms of Zn, Pb, Cd, Cu, the amount of chemical load on the channel network of the upper reach of the Ob river in the area affected by Barnaul city was calculated.

During recent years, in view of a decrease in the reserves of light oil, much attention has been paid to the ways for involving high-sulphur heavy hydrocarbon feedstock into processing. Processing of these raw materials will allow obtaining additional amounts of light distillates. Results of the studies of high-sulphur vacuum residue cracking at a temperature of 500 °C with varied process duration are presented. Typical features of the changes in the material and fractional composition of cracking products are demonstrated. Changes in the group composition of the sulphur-containing compounds of oils are investigated depending on the thermal treatment time; the kinetic regularities of the formation and destruction of the derivatives of thiophene, benzo- and dibenzothiophene are established. Changes in the structure-group parameters of resins and asphaltenes during cracking are calculated. It is shown that the cracking of resins and asphaltenes is accompanied by the formation of a large set of low-molecular-weight sulphur-containing compounds getting into cracking products. The data obtained will provide an improved understanding of thermal transformations of sulphur-containing compounds in vacuum residues during cracking.

In order to specify region-related mineral and amino acid contents in the vegetative parts of Chamerion angustifolium L . , called Ivan-Chai in Russia, growing in non-polluted environments within the Magadan Region, we analyzed the content of twenty-five chemical elements and sixteen amino acids in dry raw material (leaves) and solution (decoction). Heavy metal concentrations were found to be within permissible values. It was revealed that this species from the Kolyma area is especially valuable because its fermented leaves accumulate vitally important elements: calcium, magnesium, potassium, phosphorus, manganese, iron, copper, boron, silicon, cobalt, and it is able to meet in different extents the daily requirements of adults for these elements. The lower content of cobalt, selenium and zinc in this plant raw material in comparison with the material from other regions depicts the biogeochemical features of the northern territory. The concentrations of all the studied amino acids in Ch. angustifolium from the Magadan Region were determined to be higher than in the vegetative parts of this plant collected in the Krasnoyarsk Region. We have confirmed the opinion of a number of other authors that Ch. angustifolium is a useful prophylactic and biologically active remedy, which is able to prevent an insignificant deficit of some vital elements and may be used as a mineral dietary supplement for people of any age.