02.00.00 Chemical sciences
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Description
The present article belongs to the area of organic chemistry, namely, to chemistry of heterocyclic compounds. For the purpose of optimization of a method of synthesis the threecyclic heteroaromatic systems containing a pyridi-ne, thiophen and pyrimidine ring in one molecule, - tetrahydropyridothienopyrimidinon and dihydropyri-dothienopyrimidinon – reaction 3-aminothieno[2,3-b]-pyridine-2-carbokxamides with aromatic aldehydes is studied, some of which contain pharmacolodical groups. Reaction was carried out in the conditions of an acid catalysis – is used p-TsOH. Influence of the nature of solvent (toluene, ethanol, mix ethanol-dimethilform-amide (1:1)) on the course and the direction of reaction are studied. It is established that carrying out reaction in toluene leads to the dihydropyrimidine containing in situation 2 phenyl, 4-bromphenyl deputies. In the presence in a molecule of initial aldehyde of the deputy in orto-situation tetrahydropyrimidine are formed. Use of ethanol mainly leads to formation of a tetrahydro-pyrimidine ring. Boiling of initial substances in mix ethanol-DMF yields the results similar to use of toluene, but time of reaction is reduced twice. The way of receiving the dihydroderivatives short-term boiling of tetrahydropyrimidine is found in mix isopropanol-DMF (a volume ratio of solvents 1:3). Identity of the received substances is proved by method of a thin layer chroma-tography. The structure of the synthesized connections is confirmed with the element analysis. The structure of tertagidropirimidinon and digidropirimidinon is proved with use of data of IK and NMR 1H of the spectral analysis
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SYNTHESIS OF SUBSTITUTED PYRIDINE- 3-SULFONYL ISOCYANATES AND PYRIDINE- 3-SULFONYL UREAS
Description
Acylation of amides substituted with pyridine-3- sulfonic acids oxalil-chlorides and phosgene was studied. New pyridil-3-sulfonil isocyanates were synthesized. The conditions for this synthesis were optimized by taking into account the detailed understanding of this acylation. The synthesized pyridine-3-sulfonyl isozyanates were converted to pyridine-3-sulfonyl ureas. Biological activity of the new compounds was studied and the substances with high herbicidal effect were found
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Description
The current-voltage characteristics and the number of effective ion transfer, as well as the frequency spectrum of the electrochemical impedance of multilayer ion-exchange membranes in a stable and controllable thickness of the diffusion layer were measured, using the of rotating membrane disk complex. The article presents a comparative analysis of the frequency spectra of the electrochemical impedance of the source and a surface-modified monopolar anion exchange membranes in 0.01 M sodium chloride was made. The process of water molecules dissociation at current densities above the limiting one in 0.01 M sodium chloride solution was studied in detail
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INFLUENCE OF ORGANIC SOLVENTS ON WATER DISSOCIATION IN BIPOLAR MEMBRANE
Description
The article discusses results of experimental research of the influence of aprotic and proton solvents on reaction rate of water molecules dissociation in the bipolar membrane MB-1 by the method of electrochemical impedance frequency spectrum. It was discovered, that addition of organic component in aqueous solutions results in significant influence on the parameters of water dissociation in a bipolar region of the membrane. The reason for this influence is the reduction of the mass fraction of water in solution and, consequently, in a bipolar region of the membrane, which itself reduces the rate of the dissociation reaction. Another reason for the influence of the organic solvent is its effect on the network of hydrogen bonds existing in water and aqueous solutions. Depending on the nature of organic solvent and its concentration, the network of hydrogen bonds may be strengthened, or destroyed, thus facilitating removal of the proton involved in the reactions between water molecules and catalytic centers in cation-exchange and anion-exchange layer of bipolar membrane, or retarding removal of proton. This leads respectively to speed up or slow down the rate of dissociation in the bipolar region of the membrane, as well as changing the constants of the dissociation reaction of water. Introduction of organic solvent in solutions, which are in the contact with bipolar membrane, is a convenient method of investigating the role of solution composition on the rate of proton transfer between water molecules and catalytic centers in the membranes
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INFLUENCE OF HEAVY METALS HYDROXIDES ON WATER DISSOCIATION IN BIPOLAR MEMBRANE
Description
The results of study of bipolar membrane – analogue of MB-2, modified with chemically introduced chromium (III), iron (III) and nickel (II) hydroxides by the method of frequency spectrum of electrochemical impedance, by infrared spectroscopy and scanning electron microscopy in combination with X-ray spectrum analysis are presented. It is shown, that sequential treatment of cation-exchanger, contained in cationexchange membrane, with metal salt solution and alkali solution does not result in formation of complex compounds of these metals with ionic groups of ion exchanger. It was found that in these conditions the presence of heavy metals in the phase of cationexchanger confirmed by X-ray analysis, however, crystals of hydroxides of heavy metals are not detected in the size range of 1000 nm to 20 nm. These heavy metal compounds are thermally unstable and their catalytic activity in the reaction of dissociation of water molecules decreases with increasing temperature during heat treatment. The introduction of low-soluble hydroxides of d-metals (chromium (III), iron (III), nickel(II)) by chemical method can significantly improve the electrochemical characteristics of a bipolar membrane. The most effective catalysts in water dissociation reaction are the hydroxides of chromium (III) and iron (III) and, as a consequence, membranes with these hydroxides have a lower value of overpotential compared with original membrane at the same current density
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Description
A number of thermoreactive oligomers was obtained via the Michael interaction of molar excesses of hexamethylene-bis-maleimide with 5,5’-bisbenzotriazoles in melt. The structure of them was proved by the 13C spectroscopy method. The one-step synthesis in melt, without by-products evolution, in absence of organic solvents, additional reagents, and catalysts is the more acceptable in point of view of technology (a finished reaction product does not require any purification). The process itself is the nucleophile addition across double bond, and so it can be attributed to the atom-saving technologies. According to data of the dynamic scanning calorimetry (DSC) and the thermogravimetry (TG), oligomers fuse at 130.8–135.6 °С, cross-link at 185–250 °С, and begin their thermal destruction in air at temperatures of 400– 420 °С. The tensile strength at shear of the glued joints on base of oligomers (steel plates overlapped) is 14.2– 23.7 MPa (142–237 kgf/cm2 ). The positive effect from the introduce of 5,5’-bis-benzotriazolyl fragments into structure of bismaleimide thermoreactive oligomers on strength of the glued joints between metal plates was revealed
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Description
Macrodeficiency of polymeric materials, including the pervasive one, is a consequence of the development of initial microdefects which appear in polymers both due to external factors and during their processing. In the article, the problem of the detection of structural microdeficiency of various polymeric materials through an assessment of their structural parameters is solved. The considered materials possess approximately identical degree of crystallinity (60 – 66%), but different density. The express assessment technique of polymeric materials microdeficiency by the sorption method with the use of the academician M. M. Dubinin’s theory of volumetric micropore filling is developed and evaluated. On the basis of a quantitative assessment of sorption processes in polymeric materials, including elastomeric compositions – rubbers and rubberized fabrics, the existence of the initial local microdefects arising in the course of synthesis is established. In real polymeric materials, including elastomeric compositions – rubbers and rubberized fabrics, the existence of the initial local microdefects arising in the course of synthesis is established (the number of microdefects n varies from 1x1017 sm-3 to 6x1019 sm-3 , and the rated linear size k – from 2 nm to 7 nm). The general reduction of microdeficiency in rubberized fabrics in comparison with initial rubber is revealed and rationalized
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STUDY OF THE INTERACTION OF POLYSTYRENE-AZO-O-PHENOL-AZO-RHODANINE WITH ZINC IONS AND CADMIUM
Description
Since the industrial revolution a huge amount of pollutants emitted annually into the water most of which is occupied by toxic metals. These metals widely distributed in the environment and of accumulation of a threat to human health. It is known, that cadmium and zinc at high concentrations have a negative impact on nature. In modern wastewater treatment technology we widely use polymeric sorbents with chelating properties. The use of polymeric chelating sorbents (PCS) usage allows separating individual or group trace elements from large volumes of solutions of complex composition, lowering the limit of detection, eliminating or reducing significantly the impact of macrocomponents which increases the cleaning efficiency. The article presents the results of a study of conditions of interaction of zinc (II) ions and cadmium (II) with PCT - polystyrene-azo-o-phenol-azo-rhodanine. We found the optimal values of the conditions for zinc (II) ions and cadmium (II) sorption. We investigated the effect of interfering of the macro- and micro- water components with the sorption of the ions studied. Maximum desorption of metal ions is achieved by washing the concentrate with 10 ml of 2M hydrochloric acid. The data indicate availability of the investigated sorbent for concentration and separation of zinc (II) ions and cadmium (II)
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Description
The article is devoted to the study of enzymesantioxidants contained in horseradish root. The article provides a detailed analysis of the sources of information, aimed at clarifying the content of enzymesantioxidants contained in horseradish root, grown in the Astrakhan region in the autumn and summer. During the analysis of the literature, it was found that the content of enzyme-antioxidants in the root of the horseradish is not constant and depends on climatic conditions, planting time and harvest time. The content of antioxidants in the root of horseradish grown in the Astrakhan region in the summer-autumn period was studied using by the method of A.N. Bach and A.I. Oparin. 2 g of horseradish roots contains the number of enzymes - antioxidants able to expand for 30 min (1,547 • 100) / (20 • 1) = 77.35 mg of hydrogen peroxide in 1 min - 2.56 mg. 1mkmol As hydrogen peroxide is 0.034 mg, in 2 g horseradish contains 76 E enzyme - antioxidants (or E 38 1 g horseradish). The results of this work will form the basis for the creation and study of new enterosorbent with antioxidant functions. Enterosorbent prepared by adsorption on starch antioxidants such as peroxidase, catalase, and ascorbic acid, from aqueous extracts of plant material
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Description
The article is devoted to studying adsorption of enzymes, antioxidants contained in horseradish root on starch to create enterosorbent with anti-oxidant properties. For this goal, we have studied adsorption isotherm calculated constants, thermodynamic parameters (change of enthalpy, entropy, and isobaric-isothermal potential); sorption kinetics of enzyme-antioxidants on starch and calculate the main characteristics. The method of producing of enterosorbent - antioxidant on based starches has been developed based on the experimental data. The ready sorbent is a white powder having no taste and smell. Insoluble in biological fluids and water. It is the solid component. The enterosorbent can be used to protect the gastrointestinal tract of humans and animals against a wide variety of oxidants and peroxide. The results of this work will form the basis for the study of the antioxidant properties of the resulting enterosorbent
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