Voprosy khimii i khimicheskoi tekhnologii (Issues of Chemistry and Chemical Technology)

4-22

Authors: V.S. Protsenko

This review systematizes literature data on the use of electrochemical systems based on the novel generation of ionic liquids, deep eutectic solvents, for electrodeposition of coatings exhibiting improved electrocatalytic properties. It is shown that most published works on the topic are connected with deposition of coatings based on noble metals and iron family metals as well as their alloys and composites. The main advantages of the use of deep eutectic solvents for electrochemical synthesis of electrocatalysts are as follows: the possibility to prepare nanostructured coatings having compositions, structures and surface morphologies that cannot be achieved when using water electrolytes (including deposition of very electronegative metals); the size- and shape-controlled synthesis of deposited nanocrystals, which ensures improved electrocatalytic behavior; no need to use toxic and expensive additives, stabilizers, precursors, surfactants, etc.; and environmental issues (low hazard and fast biodegradability of the constituents of deep eutectic solvents). The prospects of creation of new high-efficient electrocatalytic coatings from electrolytes based on deep eutectic solvents are considered.

30-38

Authors: N.V. Hudzenko, V.K. Grishchenko, A.V. Barantsova, N.A. Busko, Z.V. Falchenko

The two-stage synthesis of cyclic carbonates based on methyl esters of fatty acids from rapeseed oil is characterized. The first stage involves the synthesis of epoxides by the reaction of unsaturated methyl esters of rapeseed fatty acids with hydrogen peroxide, orthophosphoric and acetic acids. The second step is a carbonization reaction, which was carried out by passing carbon dioxide through the reactive mixture in the presence of tetrabutylammonium bromide as a catalyst. A reactive oligourethane based on cyclocarbonates cyclic carbonates of rapeseed fatty acids and piperazine was synthesized by the non-isocyanate method via the interaction of cyclocarbonate group with the amino group of piperazine. Polymer composites based on synthesized cyclocarbonates, epoxides and amines of different chemical nature were prepared and studied. Thus, there is a possibility of regulating the physical and mechanical properties of epoxyurethane composites.

49-55

Authors: A.E. Kolosov, A.V. Gondlyakh, V.I. Sivetskii, D.E. Sidorov, E.P. Kolosova, V.V. Vanin, S.I. Antonyuk

An approach to the physicochemical modification of heat-shrinkable epoxy-diane polymers was considered, these polymers being used as couplings for the repair of polymer pipelines for various functional purposes. The purpose of the modification is to stabilize and improve the performance of the end couplings that are heat-shrinkable. We assessed the prospects of preparation of the products of various profiles by forming cross-linked polymers in a highly elastic state by plunger extrusion via creating favorable conditions for the orientation of interstitial fragments in epoxy-diane polymers. The starting epoxy-diane composition contained rigid and elastic components. The polymers fabricated by hardening of these compositions have both a glass transition temperature, which is convenient for operation, and high deformability in glassy and highly elastic states. We investigated the tensile strength, the elastic modulus, the failure deformation and the flaring deformation of the inner diameter of the preform of epoxy-diane polymers. Physical modification of a liquid filled epoxy-diane composition before mixing with a hardener was performed by using low-frequency ultrasonic treatment. We analyzed the results associated with the effect of combined ultrasonic treatment on the physical-mechanical and service properties of heat-shrinkable epoxy-diane polymers filled with short glass fibers.

65-72

Authors: V.S. Mazaeva, V.O. Golodnyak, I.M. Demidov, I.V. Levchuk, N.S. Sitnik, Z.I. Kovalenko, T.O. Onopriyenko

We studied the fatty acid composition of some oils and established its effect on the processes of melting and crystallization. The melting and crystallization processes were investigated by differential scanning calorimetry (DSC). To study the correlation between phase transitions and fatty acid composition, the following vegetable oils were used: sesame, corn, soybean, sunflower, coconut and jojoba. The first four oils have different fatty acid content, polyunsaturated fatty acids account for more than 50%. The presence of three phase transformations and inversion of the melting and crystallization peaks are observed in the DSC diagrams for these four oils. Coconut oil contains 93.39% of saturated fatty acids and two peaks of phase transformations are observed in the DSC diagram of melting and crystallization processes. This can be explained by the fact that the total amount of fatty acids C12:0 and C14:0 is 67.14%. Jojoba oil contains 93.89% of monounsaturated fatty acids, and 62.20% of them are presented by gondoic fatty acid (C20:1). The DSC diagram of jojoba oil exhibits one characteristic peak of phase transformation. The obtained results allow establishing a certain correlation between the parameters of fatty acid composition and DSC diagrams.

81-89

Authors: M.V. Nikolenko, K.V. Vasylenko, V.D. Myrhorodska, V.P. Kryshen, I.M. Ryshchenko

The purification of the synthesis precursors of calcium phosphates from the toxic microimpurities Cu(II), Cd(II), As(III) and Pb(II) by co-precipitation with a part of the target product was studied. It was found that a maximum extraction of Cu(II), Cd(II) and As(III) from the CaCl2 solutions was achieved in the acidic and alkaline media. When precipitating calcium phosphates from the H3PO4 solutions, the following patterns regarding the degree of co-precipitation of the microimpurities with increase of pH were observed: the degree of co-precipitation of Cd(II) decreases rapidly, whereas the degree of the co-precipitation of As(III) goes through the maximum and Cu(II) is removed completely. Pb(II) ions are also completely removed in both CaCl2 and H3PO4 solutions. It was shown that in order to purify the CaCl2 solution, it is necessary to add at least 15 g of H3PO4 per 1 dm3 of the solution and then adjust pH to the value of 2.5 to 3.0 by neutralizing the solution with ammonia. In order to remove the impurities from the phosphoric acid solution, it is recommended to carry out the co-precipitation in two following stages: firstly, the ions of Cd(II), Cu(II) and Pb(II) are removed at pH of 6.0–6.5, which requires at least 4 g of CaCl2 per 1 dm3 of the acid, and then the arsenic residues are removed at pH of 8.0–8.25, which requires at least 13 g of CaCl2 per 1 dm3 of the solution.

95-103

Authors: M.M. Plemannikov, N.V. Zhdaniuk

We showed in this work that there is a possibility of recycling the wastes derived from iron ore concentration by using glass technology. The compositions of new glass ceramics with high technological and decorative properties were developed. The influence of Al2O3, MgO and Na2O additives to the waste from ore benefication on the parameters of the synthesized glass and its crystallization products was studied. The optimal temperatures of synthesis, annealing and crystallization of glass samples in the systems (Fe2O3–FeO)–SiO2–Al2O3–Na2O and (Fe2O3–FeO)–SiO2–Al2O3–MgO were shown to be 1450100С, 500–6000С and 700–8000C, respectively. It was established that the redox conditions of crystallization of glasses in the system (FeO–Fe2O3)–SiO2–Al2O3–Na2O strongly affect the nature of the iron-containing phases that are formed: oxidative conditions favors the formation of hematite (Fe2O3) and aegirinite (Na2OFe2O34SiO2), whereas reducing conditions contributes to the formation of wustite (FeO) and fayalite (2FeOSiO2). In the system (FeO–Fe2O3)–SiO2–Al2O3–MgO under both oxidative and reducing conditions of crystallization, the same crystalline phases appear: olivine (2(Mg,Fe)OSiO2), hercin (FeOAl2O3) and iron metasilicate (FeOSiO2). It was shown that the crystallization of samples under reducing conditions allows producing materials with higher microhardness. The surface layer of glasses and glass ceramics exhibited less microhardness than their deep layers.

110-116

Authors: V.S. Protsenko, L.S. Bobrova, F.I. Danilov

Kinetics of Cr(III) ions electroreduction in a deep eutectic solvent (ethaline) was studied by using electrochemical impedance spectroscopy. The influence of water and sodium dodecyl sulfate on the kinetic parameters was established. The developed equivalent circuit included polarization resistance of the electrochemical reaction, constant phase element and finite Warburg impedance. The respective parameters of the accepted equivalent circuit were calculated and discussed. The obtained results indicated that the charge transfer is a rate-determining step of an electrochemical reaction occurring on a heterogeneous electrode surface. An increase in content of water in electrolytes resulted in an increase in polarization resistance, indicating the deceleration of Cr(III) ions electroreduction due to the changes in Cr(III) speciation. In addition, the introduction of extra water caused an increase in the value of a capacitive component of electrochemical impedance because of a rearrangement of the double electrical layer. The polarization resistance of Cr(III) ion discharge was increased in the presence of sodium dodecylsulfate in electrolyte due to adsorption of dodecylsulfate anion on the electrode surface. A Warburg impedance component disappeared in electrolytes containing relatively high water content, which was associated with corresponding reduction of solution viscosity and acceleration of diffusion mass transfer.

126-131

Authors: N.Yu. Strutynska, M.S. Slobodyanik, Y.O. Titov, T.Yu. Sliva

We investigated the features of complex substitution in anionic (PO43–CO32–) and cationic (Ca2+M+, M+ – Na, K) sublattices of apatite-type calcium phosphate during wet precipitation. The nanoparticles (10–35 nm) of apatite-related calcium phosphates were prepared from the aqueous solutions of the system М+–Ca2+–CO32––PO43––NO3– at determined molar ratios Ca2+/PO43–=1.67, CO32–/PO43–=1.0 and М+/PO43–=3.0 and 6.0 at the temperature of 250C. The positions of characteristic vibrations of carbonate groups in the FTIR spectra of the prepared samples in the regions of 1500–1400 cm–1 and 880–870 cm–1 confirmed the realization of partial substitution of РО43– by CО32– (B-type) in apatite-type structure. Results of elemental analysis indicated that the presence of potassium cations in the initial solution promoted the anionic substitution in calcium phosphate structure. The study of the activity of the synthesized carbonate-containing calcium phosphates in vitro revealed their tendency to gradual dissolution without a significant effect on the pH of the medium, which indicates the prospects of the synthesized samples in bone engineering.

139-149

Authors: N.O. Chorna, V.M. Kordan, A.M. Mykhailevych, O.Ya. Zelinska, A.V. Zelinskiy, K. Kluziak, R.Ya. Serkiz, V.V. Pavlyuk

Electrochemical hydrogenation, lithiation and sodiation of the phases GdFe2–xMx and GdMn2–xMx (M=Mn, Co, Ni, Zn, and Mg) and the influence of doping components on electrochemical characteristics of electrode materials on their basis were studied using X-ray powder diffraction method, scanning electron microscopy, energy dispersive X-ray analysis, X-ray fluorescent spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Phase analysis showed a simple correspondence between unit cell parameters of the phases and atomic radii of doping elements. Electrode materials based on GdFe2 and GdMn2 doped with 2 at.% of Co, Ni and Mg demonstrated better hydrogen sorption properties than those doped with Mn and Zn. Corrosion resistance of the doped electrodes was also better than of the binary analogues (e.g. corrosion potential of the GdFe2-based electrode was –0.162 V whereas that of GdFe1.96Ni0.04 was –0.695 V). The capacity parameters were increased in the following ranges: Zn

3-11

Authors: A.P. Avdeenko, S.A. Konovalova, I.Yu. Yakymenko, V.M. Baumer, S.V. Shishkina, V.V. Pirozhenko

Hydrazones of 1,4-benzoquinone, which have a wide range of biological activities, can be synthesized in the reactions of 4-{[(arylsulfonyl)oxy]imino}cyclohexa-2,5-diene-1-ones or N-(4-oxocyclohexa-2,5-diene-1-ylidene)arylsulfonamides with N-substituted hydrazines. In this study, the reaction of 2,6-disubstituted 4-{[(tolyl(methane)sulfonyl)oxy]imino}cyclohexa-2,5-diene-1-ones with aroylhydrazides gave N'-(3,5-dialkyl-4-oxocyclohexa-2,5-diene-1-ylidene)aroylhydrazides, which can be obtained by cross-synthesis in the reaction of N-(3,5-dialkyl-4-oxocyclohexa-2,5-dien-1-ylidene)arylsulfonamides with aroylhydrazides. As a result of the reaction of 4-{[(tolyl(methane)sulfonyl)oxy]imino}cyclohexa-2,5-dien-1-ones with phenylhydrazine, stable 4-hydroxyanilinium tolyl(methane)sulfates were isolated. Their structures were confirmed by X-ray diffraction data. We suggested that at the first stage of the reaction between 4-{[(tolyl(methane)sulfonyl)oxy]imino}cyclohexa-2,5-diene-1-ones and hydrazines, the N–O bond of starting 4-(oxyimino)cyclohexa-2,5-diene-1-one was broken forming sulfonic acid and corresponding quinoneimine. The latter either can be reduced to corresponding aminophenol under reaction conditions or can react with an excess of N-substituted hydrazine yielding corresponding hydrazide. The formation of N'-(4-oxocyclohexa-2,5-diene-1-ylidene)arohydrazides is facilitated by a lower basicity of hydrazide and a lower redox potential of quinoneimine.

16-23

Authors: V.V. Halysh, M.I. Skiba

We investigated chemical composition and sorption properties of lignocellulosic complexes of wastes of agroindustrial complex, namely crushed shells of apricot, cherry and peach seeds, and walnut shells. Chemical analysis revealed that walnut shells show the highest content of polysaccharide components. Cherry and peach seed shells are characterized by a higher content of aromatic components (lignin). Based on the results of sorption of benzene vapor, the following sequence of the volumes of adsorption pores was found: walnut shells (0.03 cm3 g–1)=apricot seed shells (0.03 cm3 g–1)>peach seed shells (0.02 cm3 g–1)>cherry seed shells (0.01 cm3 g–1). The sorption capacity of biosorbents towards methylene blue was investigated as a function of pH of an aqueous solution, process duration, and initial dye concentration. It was established that the maximum efficiency of sorption is achieved at pH 6, while the minimum value corresponds to low pH values. Probably, an increase in pH value leads to deprotonation of carboxyl groups of biosorbents followed by changes in their surface charge into negative. This causes a decrease in electrostatic repulsion forces between the positively charged dye cation and the surface of the biosorbents. Therefore, the sorption centers are formed. The data on kinetics of sorption showed that during the first 30 min of contact the absorption of 55–60% of the dye cations occurs on the biosorbents, whereas complete sorption equilibrium is achieved within 120–180 min. The following sequence of the sorption capacity of lignocellulosic materials towards methylene blue was established: apricot seed shells (43.9 mg g–1)>walnut shells (37.8 mg g–1)>peach seed shells (30.1 mg g–1)>cherry seed shells (26.5 mg g–1). The Freundlich isotherm is the most suitable for describing the cationic dye absorption by biosorbents, and the calculated values are in good agreement with the experimental data.

35-44

Authors: O. Kostiv, O. Korkuna, M. Sheredko

We developed two fast, simple and sensitive spectrophotometric methods for the determination of ceftazidime in drugs by using phenolic reagents resorcinol and 2-methylphenol. The methods are based on a previous antibiotic diazotization in the medium of hydrochloric acid (CHCl=12 M) and its following azo coupling with reagents in an alkaline medium with the formation of effective analytical forms that allow determining ceftazidime and have maximum absorbance at 519 nm and 516 nm for resorcinol and 2- methylphenol, respectively. The azo coupling products of diazotized ceftazidime exhibit effective molar absorptivity in the range of (6.31–6.84)103 M–1 cm–1. Stoichiometric ratios of the azo compounds components were established using continuous variations methods and they were the same in both cases (1:1). The developed methods allow determining from 2.75 to 185.5 g mL–1 of ceftazidime with resorcinol (LOQ=2.54 g mL–1) and 0.32191.3 g mL–1 of ceftazidime with 2-methylphenol (LOQ=0.28 g mL–1). The developed methods have been successfully tested in the analyses of one-component preparations (powders for injection solutions).

55-61

Authors: L.K. Patrylak, A.V. Yakovenko

Alkylation of isobutane with butenes is one of few important petrochemical processes that is still implemented using liquid acids. New highly active solid alkylation catalysts are investigated for century. The development of new rapid methods for testing catalysts will contribute to progress in this area. Therefore, the aim of the work was to test the possibility of conducting a bimolecular reaction of alkylation of isobutane with butenes in a microreactor in a pulsed mode of feeding. A zeolite-containing alkylation catalyst was synthesized and characterized by X-ray diffraction analysis, temperature-programmed desorption of ammonia and low-temperature nitrogen adsorption. Catalytic studies were performed in a microreactor built into the gas chromatograph scheme, which provided online analysis of the reaction products. The isobutane /butenes mixture was fed into the helium carrier gas stream via a loop. Testing was performed at 80, 100, 135 and 1850C. It was found that a significant amount of products is not desorbed by the carrier gas and is retained by the catalyst at reaction temperatures, while an increase in desorption temperature to 3800C promotes removing the products from the catalyst surface. The highest yield of products was 27% at 800C. With increasing the reaction temperature, the yield drops to 15%. It was shown that the developed method of testing of alkylation catalysts is promising for further use in the search for efficient solid-phase alkylation catalysts.

71-78

Authors: N.M. Rezanova, Yu.O. Budash, V.P. Plavan, V.I. Bessarabov

The influence of nanoparticles made of ifferent metals oxides (ZnO, Al2O3, TiO2, and ZnO/Al2O3) on the in situ formation of microfibrils by the components of a dispersed phase was studied in a thermodynamically incompatible blend of polypropylene/copolyamide (PP/CPA). The viscosity of the melts was determined by capillary viscometry method. Elastic properties were evaluated by the degree of extrudate swelling. The morphology of the compositions was studied by optical polarization microscopy. The method of image analysis was used to quantify the structural characteristics of the blends. It was established that the introduction of 1.0 wt.% of nanoparticles of the studied oxides made from different metals allows tuning the microstructure of the melt of the PP/CPA blend, which is realized in the course of extrusion. More perfect morphology is formed in nanofilled systems: the average diameter of PP microfibrils decreases and their mass fraction increases. The modifying effect of oxide nanoparticles is manifested due to their influence on interfacial phenomena and rheological properties of nanofilled PP melt. The viscosity of the PP melts increases and their elasticity decreases in the presence of nanoparticles of the studied metal oxides. The values of the ratio of the viscoelastic characteristics of the dispersed phase and the matrix in nanofilled systems depend on the nature of oxide and indirectly correlate with the microstructure of the extrudate. As these ratios approach unity, the diameter of PP microfibrils decreases and their share increases. The efficiency of the studied oxides to improve the microfibrillar structure increases in the following series: ZnO, Al2O3, TiO2, ZnO/Al2O3. The obtained results demonstrate the possibility to create the microfiber textile and filter materials with improved consumer characteristics by adjusting the phase morphology of the blends.

90-100

Authors: L.L. Rudneva, S.I. Bukhkalo, O.V. Lakiza, O.V. Chervakov

We investigated the possibility of a complex use of vegetable waxes as modifiers of surface properties of polymeric composites. The wax samples were extracted from vegetable raw materials and then introduced into the rubber formulations used for the manufacture of the sidewalls of passenger tires and pigmented paints as a dispersant additive. Physical-mechanical properties of the obtained compositions were determined. The introduction of the investigated wax into serial rubber formulations does not impair the technical characteristics of the mixtures. The investigated waxes ensure a good protection of the elastomeric compositions against atmospheric aging. The waxy substances can be effectively used as additives that increase the ability of inorganic pigments to dispersion. The results showed that the introduction of the wax increased the hardness of the film coatings of paint-and-lacquer materials, the gloss of the prepared coatings being not substantially decreased.

4-19

Authors: T. Vislohuzova, R. Rozhnova, N. Galatenko

This review is devoted to implant materials for bone tissue. A variety of bone implants in termrs of their chemical nature (auto-, allo-, xenogenic, metallic and polymeric composite materials), their advantages and disadvantages are characterized. The relevance and prospects of using epoxy resins for medical applications are shown. Particularly the creation of composite materials based on epoxy resins with enhanced physical-mechanical properties is of great importance, since they are suitable for the production of bone implants. Composite materials prepared by the chemical modification of epoxy resins via polyurethane, which provides an increase in biocompatibility and elasticity, and by the physical modification via biologically active substances, which causes a local therapeutic effect of the composites, can be considered as an alternative to existing implants. Biocompatible biologically active fumarate-containing epoxy polyurethane composite materials filled with ferrocene exhibit an increased capacity for biodegradation due to introduction of oligooxypropylene fumarate into their structures, a prolonged therapeutic effect of ferrocene, which is manifested in the stimulation of bone regeneration, and improved physical-mechanical properties sufficient to perform the functions of under bone plates for osteosynthesis.

26-32

Authors: Yu.G. Voloshyna, O.P. Pertko, L.K. Patrylak, A.V. Yakovenko

Platinum group metals are widely used as a hydrogenating-dehydrogenating component of a number of petroleum refining and petrochemical catalysts, in particular for isomerization of linear alkanes. The main direction in improving the preparation of these catalysts is to reduce their cost by optimizing the metal component amount. However, insufficient attention was paid to the method of introduction of an active metal into the carrier; at the same time, this issue is especially important in case of zeolite catalysts, for which ion exchange can be used in addition to traditional impregnation. Therefore, the purpose of this work was to compare the catalytic efficiencies of Pd-containing MFI zeolites in which metal was introduced by two methods: impregnation from a solution of palladium chloride and ion exchange from tetraamminepalladium(II) chloride in the amount of 0.5 wt.% in terms of pure metal. Study of texture characteristics by nitrogen low-temperature adsorption/desorption technique showed that the specific surface area of samples and the total sorption volume remained practically unchanged, regardless of the procedure of metal component introduction. A significant decrease in average pore size was observed only in case of ion-exchange metal introduction; this indicated the localization of palladium mainly in zeolite pores, which was confirmed by transmission electron microscopy. The stage of transformation from ammonium form to hydrogen one strongly affects the activity of samples, this stage should precede the final stage of metal recovery. The highest yield of hexane isomers of about 46.5 wt.% with the selectivity of 88.7% was observed over a catalyst with Pd introduced by ion-exchange method with the smallest palladium particles (3–7 nm).

38-43

Authors: Y.V. Husak, A.A. Ovcharenko, A.A. Golichenko, A.V. Shtemenko

The previously developed methods for the synthesis of cis-tetrachlorodi--carboxylates of dirhenium(III) were modified, due to which the derivatives of Re26+ with proteinogenic amino acids (AA) isoleucine, serine and proline were synthesized for the first time. The composition and structure of these substances with the general formula cis-[Re2(АA)2Cl4(CH3CN)2]Cl2 were confirmed by elemental analysis, electron adsorption and IR spectroscopy. The presence of a characteristic peak, which corresponds to the *-electronic transition of the Re–Re quadruple bond for compounds with the cis-arrangement of two bridging-coordinated carboxylate groups in the ligand environment of the Re26+ cluster, was showed by using the data on the electronic absorption spectra of solutions of the synthesized compounds. The IR spectrum contains an intense, weakly split band in the region of 1466–1458 cm–1, which is attributed to the s(CO) coordinated carboxyl group and indicates its bridging coordination to the binuclear Re26+ fragment. The spectra exhibited the presence of bands of stretching (NH3+) and bending vibrations (NH3+) of protonated amino groups in complex compounds of isoleucine and serine and the presence of bands of stretching (NH2+) and bending vibrations (NH2+) of the protonated imino group of proline. The stability of the prepared complex compounds in aqueous solutions was investigated. It is shown that the hydrolysis of the synthesized substances occurs within 9–14 days with a decrease in the pH of the reaction solution due to a gradual replacement of labile chloride ligands by OH–-groups at the first stages of interaction with water. The resistance to hydrolysis is an important parameter of biologically active substances; the determination of the resistance to hydrolysis will expand understanding of the possible mechanisms of their specific biological activity.

50-58

Authors: V. Zazharskyi, M. Parchenko, V. Parchenko, P. Davydenko, O. Kulishenko, N. Zazharska

The alkylation of 5-(5-bromofuran-2-yl)-4-methyl-1,2,4-triazole-3-thiol with bromoalkanes was carried out. Synthesis was accomplished by addition of equivalent amounts of bromoalkanes (bromomethane, bromoethane, bromobutane–bromodecane) to 5-(5-bromofuran-2-yl)-4-methyl-1,2,4-triazole-3-thiol in a methanol medium in the presence of an equivalent amount of sodium hydroxide. Compounds were obtained with a high yield. The next step was to investigate the reaction of 5-(5-bromofuran-2-yl)-4-methyl-1,2,4-triazole-3-thiol with some other halogen-containing compounds, the mechanism of the reaction of which also relates to nucleophilic substitution. As halogen-containing compounds, we used bromoacetone, bromoacetophenone, chloroacetic acid and chloroacetamide. Under these conditions, a series of new compounds were synthesized. Structure of compounds was confirmed by 1H NMR spectroscopy and elemental analysis. The antibacterial activity of the synthesized compounds towards cryogenic strains of Enterobacteriaceae, Pseudomonadaceae, Staphylococcaceae, Bacillaceae, Listeriaceae, Corynebacteriaceae and Saccharomycetaceae families in vitro was also investigated. According to the data obtained, one can conclude that the investigated compounds can compete with kanamycin, a natural broad-spectrum antibiotic from the second generation of aminoglycosides, whose range of action includes gram-positive and gram-negative microorganisms. The compounds involved may be recommended for further investigation of their action against multi-resistant strains of microorganisms.

69-74

Authors: E.V. Karasik, Yu.S. Hordieiev

Glasses of the system RO–Al2O3–B2O3–SiO2 are used as a base for the fabrication of heat-resistant nonmetallic materials and general-purpose products. The purpose of this work is to develop mathematical models for calculating the temperature coefficient of linear expansion, glass transition temperature and density as a function of the composition of glass in the oxide system RO–Al2O3–B2O3–SiO2 where RO=BaO, SrO, CaO, MgO, ZnO. The disadvantage of the known models is that the range of their application is limited by the quantitative content of components in the glass. At the same time, an increase in the sample size of experimental compositions made it possible to obtain more accurate mathematical models for calculating these properties. The glasses included in the experimental sample are distinguished by a wide range of temperature coefficient of linear expansion (from 30 to 10510–7 К–1). The glass transition temperature of these glasses is within the range of 580–7100C, which allows a reasonable approach to the choice of temperature regime for the formation of the structure vitreous and glass-ceramic materials for different functional purposes. The mathematical models were developed with the use of the experimental and statistical method. The obtained mathematical models are adequate to the experimental data and allow calculating the thermal expansion, glass transition temperature and density of glasses; the mean-square deviations of temperature coefficient of linear expansion, glass transition temperature and density being 1.910–7 К–1, 16.00C and 0.06 g cm–3, respectively. Their accuracy is sufficient for the development of basic glass compositions for various functional purposes.

83-90

Authors: L.F. Kosyanchuk, O.I. Antonenko, T.D. Ignatova, N.V. Babkina, O.V. Babich, O.M. Gorbatenko, O.O. Brovko

An optically transparent material with enhanced physical-mechanical properties was synthesized, which is based on the in situ formed sequential interpenetrating polymer networks of poly(methyl methacrylate)/polyurethane with an oligoester component. The kinetic features of polymerization of methyl methacrylate in these systems were studied. It was established that the polymerization rate of methyl methacrylate increases with an increase in the content of a polyurethane component, which results from an increase in the system viscosity. Irrespective of the content of polyurethane (15, 20 or 25 wt.%), optically transparent materials with a light transmission coefficient of about 90% were formed. The method of dynamic mechanical analysis showed that the modification of cross-linked poly(methyl methacrylate) with cross-linked polyurethane led to a decrease in the value of the elastic modulus; the value of the loss modulus being increased with an increase in polyurethane content. This indicated bot a decrease in fragility and the improvement in impact strength of the glass-like material. According to the study of physical-mechanical properties of the materials, the presence of polyurethane in their composition resulted in an increase in the impact strength and relative breaking elongation and in the reduction of the Young modulus. It was found that the interpenetrating polymer network containing 20% of polyurethane showed the best values of breaking strength, breaking elongation and Charpy impact.

99-105

Authors: Yu. Melnyk, A. Tierin, S. Melnyk

The activity of heterogeneous catalysts for the transesterification reaction of sunflower oil triglycerides with aliphatic alcohols of normal structure was investigated in this work. Fine-dispersed oxides ZnO, NiO, FeO, CuO and MnO served as catalysts. The following aliphatic alcohols were used in the transesterification process of sunflower oil triglycerides: methanol, ethanol, propan-1-ol and butan-1-ol. The transesterification reaction was performed under the conditions as follows: the content catalyst of 0.25 wt.%, the triglycerides:alcohol molar ratio of 6.5:1 and the temperature of 333 K (methanol) or 348 K (ethanol, propan-1-ol and butan-1-ol). The investigated metal oxides were arranged in series according to their activity towards the transesterification reaction of sunflower oil triglycerides with C1–C3 alcohols. It was established that these series were practically the same for the mentioned alcohols. Similarity between the oil conversion curves of the reaction duration for C1–C3 aliphatic alcohols in the presence of all studied catalysts was shown. The use of the most active catalysts (ZnO and NiO) for the transesterification reaction of triglycerides with C1–C3 aliphatic alcohols allowed achieving the triglycerides conversion of more than 95% at the reaction duration of 2.5 h. Iron and manganese oxides exhibited relatively high catalytic activity in the transesterification reaction with aliphatic C1–C2 alcohols. However, the oil conversion was only 86.7–91.1% for the transesterification reaction by propan-1-ol in the presence of above-mentioned catalysts under the optimal conditions (reaction duration of 2.5 h). Copper oxide exhibited the lowest activity among all catalysts that were tested. The highest initial reaction rate in the presence of metal oxides was achieved in the transesterification of sunflower oil triglycerides by methanol. The reaction rate of triglycerides transesterification by butan-1-ol was by three orders of magnitude lower than that achieved by using of other alcohols.

115-123

Authors: P.P. Moskvin, W. Sadowski, V.B. Kryzhanivskyy, G.V. Skyba, L.G. Polonsky

Superthin layers in ZnO and ZnO–CdO systems, which are intended for the use as transparent electrodes of modern optoelectronic devices, were synthesized by modified sol-gel method. The ranges of parameters of the technological process were established to obtain high-quality layers of material on glass substrates. Surface morphology depending on the synthesis conditions was studied by scanning electron microscopy. SEM images of the surface served as a basis for the multifractal analysis of the surface areas and volumes of nanoforms that are formed on the surface of the obtained layers. The dependences of the multifractal parameters of the surface nanoforms characterizing the surface state were determined as a function of the temperature of the final annealing of the layers. The relationships between Rainier numbers and fractal ordering parameters describing the surface geometry of the layers with the temperatures of the final annealing were established. The numerical values of the fractal characteristics of the obtained surface were used to estimate the influence of the fractal surface geometry on the value of the molar surface energy of the layers.

134-141

Authors: M.V. Nikolenko, K.O. Elchaninova, V.O. Karabut, O.Yu. Vashkevych

In order to determine the mechanism and factors of optimization of the process of extraction of anthocyanin dyes from crushed grape pomace, the kinetics of the process at the temperatures of 14 and 800C was studied using aqueous and aqueous-ethanolic solutions under conditions of intensive mixing. For the theoretical description of the kinetic data, a model of the extraction process from a porous solid body was used under conditions of relatively small values of constrained diffusion coefficients. It was established that the experimental data are well described by the equation for the internal diffusion mechanism of the extraction process. It was shown that the experimental data are also well described by the Yander equation proposed for modeling diffusion-controlled heterogeneous processes with constant parameters of the diffusion. It was concluded that both equations are similar to each other and differ only in the coefficients at the degrees of transformation, which is due to the assumptions that were made in their derivation. The conclusion about the nature of the limiting stage of the process of extraction of anthocyanin dyes was confirmed by calculations of the apparent activation energy, the value of which was 14.0 kJ mol–1. The obtained data allowed determining the factors of optimization of anthocyanin extraction process from grape pomace: particle size of raw materials, anthocyanin concentration in solution, temperature, ethanol content in solution, solution acidity, degree of plant cell destruction and ultrasonic treatment.

151-158

Authors: V.V. Pischanskaya, M.V. Hubynskyi, A.Yu. Usenko, A.V. Sybir, K.M. Sukhyy, S.S. Fedorov

The article presents the results of the study aimed at establishing the main process parameters of the preparation of an electrically conductive composite material containing silicon carbide, graphite, aluminous cement and sodium silicate. This composite material can be used as a heating element in heat accumulators for the operating temperature range of 600–10000C. The effects of the amount of sodium silicate within the range of 12–18 wt.% and the compacting pressure within the range of 40-70 N / mm2 on the changes in the properties of the samples after drying were investigated. It was established that the mechanical strength of the samples of 34.2 N mm–2 and 33.4 N mm–2 can be achieved at the compacting pressure of 60 N mm–2 and 50 N mm–2 and the sodium silicate content of 14 wt.% and 16 wt.%, respectively. It was shown that a porous microstructure of the composite is formed in the course of samples annealing at the temperatures of 600–10000C due to physicochemical processes of transformations of sodium silicate and its interaction with aluminous cement; this porous microstructure is characterized by open porosity in the range of 23.14–25.11% and mechanical strength in the range of 33.2–32.0 N mm–2. The fabricated composite material after its annealing at 10000C shows a low electrical resistivity of 0.06710–2–0.01410–2 Ohmm at the electric current of 28–94 A and the voltage of 19.2–13.2 V.

165-170

Authors: N.V. Smetanin, S.A. Varenichenko, E.V. Zaliznaya, A.V. Mazepa, O.K. Farat, V.I. Markov

The catalyst-free sp3 C–H functionalization of tetrahydroacridine(quinolines) derivatives has been achieved using a Michael-type reaction with N-arylmaleimides. This method enables the facile synthesis of biologically important N-aryl bearing tetrahydroacridine(quinolines) moieties in a single step with high yields. The reaction occurs under non-catalytic conditions by heating of hydroacridines(quinolines) in DMSO within 4 h at 100–1200C. The reaction between starting compounds allows synthesizing (3S/4R)-3-[(3R/4S)-9-chloroacridine(quinoline)-4-yl]-1(-N-aryl)pyrrolidine-2,5-diones with a good yield. The structure of compounds was proved by spectral methods of analysis. The 1H NMR spectrum shows characteristic signals of protons of the CH-groups in acridine(quinoline) (3.4–3.5 ppm) and pyrrolidine (3.8–3.9 ppm) cycles. It is interesting to note that the main direction of the fragmentation is the Michael retro-reaction, which is accompanied by the elimination of 1-(2-nitrophenyl)-1H-pyrrole-2,5-dione and leads to the formation of m/z ions of starting chloroacridines(quinolines).

3-10

Authors: R. Apostolova, E. Shembel, B. Markovsky, D. Aurbach

Thin-layer Со9S8 electrodes were synthesized via the electrolysis technique onto aluminum foil and tested in redox reactions with lithium in polymer and liquid electrolytes. It was established the difference between the discharge characteristics of the Co9S8-electrode in the polymer electrolyte with a gel-like consistency and in solid film electrolyte. The starting discharge capacity of Со9S8 both in a gel-like electrolyte and in a liquid electrolyte may reach 600 mAh/g, which exceeds its theoretical value (544 mAh/g). The reversible capacity of Со9S8/Li in the polymer electrolyte is about 280–250 mAh/g at the average discharge voltage of 1.40–1.45 V. During a long cycling, the discharge capacity of Co9S8 decreases both in the polymer electrolyte and in the liquid electrolyte. The discharge capacity of a metal-sulfide material/Li system in the polymer electrolyte is mainly reduced due to an increase in the polarization resistance of the lithium electrode caused by the disruption of its contact with the polymer electrolyte and a drying of the electrolyte in the porous space of the polymer gel matrix. The irreversible capacity of Со9S8/Li can be reduced under the influence of an anionic polyelectrolyte (sodium polyacrylate) that was used as an additive to the electrolyte for the synthesis of Со9S8. Norit conductive filler added to the electrolyte for the synthesis of Со9S8 was tested to improve the electrochemical characteristics of Co9S8. A positive effect of Norit may be associated with the stabilization of the reversible capacity of Со9S8 electrodes that reaches 400 mAh/g.

18-23

Authors: D.S. Katruk, V.Ye. Levytskyi, A.S. Masyuk, B.I. Kulish, Yu.Ya. Melnyk

The influence of polymer modifier of polyvinyl chloride on the structuring process of unsaturated polyester resins in the presence of dibutyl phthalate was investigated. The results of viscometric study of modified polyester materials showed that the introduction of polyvinyl chloride into the polyester composition accelerates an increase in the viscosity of the studied systems. It was established that the modification of unsaturated polyester resin by polyvinyl chloride in the presence of a plasticizer, particularly dibutyl phthalate, is accompanied by the following physicochemical processes: swelling and partial dissolution of polyvinyl chloride in styrene solution of polyester and plasticizer, diffusion of system components, and sedimentation of polymer macromolecules. The passage of these processes is determined by the nature of intermolecular and interfacial interactions between all components. The effect of polymer modifier of polyvinyl chloride on the morphology and nature of intermolecular interactions in polyester compositions was established. Polyester materials modified by polyvinyl chloride exhibited the changes in the intensities of the absorption bands and their shifts in the spectra, which was obviously due to both the influence of the polymer modifier on the process of polyesters structuring and the occurrence of hydrophobic interactions between the polyester matrix and the macromolecules of polyvinyl chloride. The influence of the nature of metal-containing silicate fillers on the kinetic and thermometric patterns of curing of composites based on modified polyester oligomers was investigated.

30-35

Authors: E.E. Kostenko, E.N. Butenko, M.A. Bondarenko

This work was devoted to the study of the complexation of Pb(II), Hg(II) and Cd(II) with ethyl maltol (EtMal). Formation of complexes with the following ratio of components M:EtMal=1:1 was established by the method of equilibrium shift using metallochromic indicators. The concentration of ligand (EtMal) was used as a criterion for assessing the relative stability of the complexes of lead(II), mercury(II) and cadmium(II) with ethyl maltol, which is necessary to reduce the output color of the solution of the indicator complex by half, that is to create a certain equilibrium concentration of free metal ions in the system. This value was determined by studying the equilibrium in comparison systems Cdxylenol orange–C2O42–; Pbsulfonazo III–C2O42– and Hgsulfonazo ІІІ–CH3COO–, since there are reference data on the stability of oxalate complexes of cadmium and lead as well as acetate complexes of mercury. The conditional stability constants of the complexes were established as follows: lgPb(EtMal)=5.870.28, lgHg(EtMal)=5.750.13 and lgCd(EtMal)=5.000.18. It was found that the stability of complexes of Pb(II) and Cd(II) with EtMal is higher than with Mal. This means that the introduction of an ethyl radical into the maltol molecule promotes the formation of complex compounds. It was shown that the stability of the complexes of Pb(II) and Hg(II) with EtMal is higher than that of the Cd(II) complex. The information obtained can be used to develop new spectrophotometric methods for the determination of ethyl maltol in different food and cosmetic products as well as metal ions which form complexes with EtMal.

46-52

Authors: O.B. Mykhalichko, V.M. Mykhalichko, A.O. Fedorchuk, M.F. Fedyna

Crystal structures of the following ternary compounds were studied by X-ray powder method: NdCu5Ga6 (DRON-4.0 diffractometer, FeK-radiation, structure type (ST) BaCd11, Pearson symbol (PS) tI48, space group (SG) I41/amd, a=10.298(2) Å, c=6.625(2) Å, RB=0.0478, Rp=0.0454, 2=2.89), GdCu6.87Ga4.13 (DRON-4.0 diffractometer, FeK-radiation, ST BaCd11, PS tI48, SG I41/amd, a=10.2687(15) Å, c =6.60034(10) Å, RB=0.0414, Rp=0.0274, 2=1.86); and YbCu4.75Ga6.25 (STOE STADI P diffractometer, CuK1-radiation, ST BaCd11, PS tI48, SG I41/amd, a=10.3088(11) Å, c=6.6136(8) Å, RB=0.03854, Rp=0.0348, 2=3.46). The crystal structure of R(Cu,Ga)11 compounds is closely related to SmCu6.2Ga4.8 structure type according to the nearest coordination environment around the least electronegative atoms. The both structure types are realized at 8.33 at.% of R in the ternary systems R–Cu–Ga. The crystal structure of investigated compounds can be deduced from the structure of binary (RCu6, RGa6) and ternary (R2(Cu,Ga)17, R(Cu,Ga)12) phases. All structure types involve polyhedron in the form of a hexagonal prism with different number of additional atoms. The nearest coordination environment around R atoms transforms into the hexagonal antiprism with ten additional atoms in the structure of R(Cu,Ga)11 compounds.

63-67

Authors: O.P. Perepelytsya, V.M. Ischenko, T.V. Petrenko, V.І. Maksin, T.I. Ushchapivska

In this study, X-ray amorphous double molybdates of rare earth elements and methylammonium CH3NH3R(MoO4)2H2O (where R=Ce–Lu) were synthesized in aqueous solutions of rare earth elements salts and methylammonium chloride under the excess of methylammonium molybdate at the temperature of 20–250C. It was established that these substances have a stoichiometric composition with the following formula CH3NH3R(MoO4)2H2O. The study demonstrated that the compounds CH3NH3R(MoO4)2H2O (R=La–Y) belong to -TlYb(MoO4)2H2O structural type with distorted monoclinic structure of a layered rhombic KY(MoO4)2. According to the obtained data, the synthesized substances are X-ray amorphous with particle size less than 100 nm; therefore, they may be used in catalytic processes without additional grinding. We showed the possibility of deposition of double molybdates of rare earth elements and methylammonium on the carriers containing hydroxyl groups or oxygen-containing anions (such as hydroxides of aluminum, iron (III) or cobalt (II), silica gel and natural clays). It was stated that the prepared compounds may be used as components in catalysts of oxidative dehydrogenation of alkanes and alcohols. The products of thermal decomposition of CH3NH3R(MoO4)2H2O in a vacuum, protective or hydrogen atmosphere at the temperatures of up to 4500C can be used as catalysts for fuel cell anodes due to the lower degrees of molybdenum oxidation.

73-80

Authors: N.V. Polish, N.G. Marintsova, A.I. Karkhut, L.R. Zhurakhivska, R.T. Konechna, O.Y. Voskoboynik, S.I. Kovalenko, V.P. Novikov

This work describes the synthesis and a convenient method for obtaining new 1,2,4-triazine- and 1,2,4-triazole-containing 1,4-naphthoquinone derivatives. The studied 1,5-binucleophiles react with 1,4-naphthoquinone via only one nucleophilic center of the molecule, the aniline fragment. 2-(2-(6-aryl-5-oxo-2,5-dihydro-1,2,4-triazin-3-yl)phenyl) amino) naphthalene-1,4-dione and 2-((2-(3-aryl-1H-1,2,4-triazol-5-yl)phenyl) amino) naphthalene-1,4-diones were prepared by bonding of an amino group to the electron-deficient double bond of 1,4-naphthoquinone followed by oxidation of formed 1,4-diol with an excess of 1,4-naphthoquinone. The biological activity of the synthesized 1,2,4-triazine- and 1,2,4-triazole-containing 1,4-naphthoquinone derivatives was evaluated by using PASS Online and Gusar software. High anticancer and antimicrobial activity and low toxicity of the obtained substances were predicted, which allows considering this class of organic compounds as a promising one in terms of preparation of new drugs. 1,2,4-Triazole-containing naphthoquinone derivatives are likely to be histidine kinase inhibitors and may be promising antimicrobials. The conducted primary screening of biological activity and toxicity of the synthesized compounds testified to high expediency of further experimental studies of anticancer and antimicrobial activity in order to find new effective drug substances.

88-97

Authors: A.V. Slyuzar, Ya.A. Kalymon

The changes in the redox properties of the quinhydrone solutions at different concentrations and ratios of quinhydrone, Na2CO3, and Na2S2O3 during their exposure to free air were investigated by cyclic voltammetry method. It was found that the potential of platinum in the quinhydrone solutions at the concentration of 5 g dm3 (0.023 mol dm3) increased with an increase in the molar ratios of sodium carbonate to quinhydrone from 0.25:1 to 5:1 and sodium thiosulfate to quinhydrone from 0.4:1 to 40:1, whereas the potential of platinum decreased with increasing the exposure time. The cyclic voltammetry curves showed the currents peaks of the oxidation and reduction of the oligomerization products of quinhydrone. During the exposure of carbonate solutions of quinhydrone (5 g/dm3), a decrease of the current of the oxidation peaks was observed and a complete attenuation of the oxidation processes was detected by 5th day of the exposure. However, the oxidation currents were still quite high for 5 days of the exposure in the solutions with higher concentrations of quinhydrone (10–30 g dm3). Due to a high activity of oligomerized products, the formation of sulfosubstituted quinone compounds occurred in the initial stages of the exposure of carbonate-thiosulfate solutions of quinhydrone.

104-111

Authors: L.M. Yashchenko, N.V. Iarova, L.О. Voronzova, O.O. Brovko

Physical-mechanical properties of biocomposites based on epoxy urethane binders were studied as a function of the ratio of components (polyisocyanate, epoxy resin ED-20 and sodium silicate) and the amount of a filler (hemp wood core) before and after the action of some destructive factors. It was shown that the mechanical properties of the prepared biocomposites were determined by the polymer–filler interaction. The balance and distribution of physical intermolecular bonds between the components of the system play an important role too. It was established that a significant difference in the parameters of physical and mechanical properties of biocomposites with different ratios of epoxy urethane binder components was due to different thermodynamic affinity of the binder to the hemp wood core surface. The study of the effect of the amount of a filler on the physical and mechanical properties of biocomposites showed that an increase in the concentration of hemp wood core from 60 parts by weight up to 80 parts by weight reduced the flexural strength from 30.1 MPa to 25.6 MPa, respectively. This was due to the insufficient amount of binder to wet the entire surface of the filler, and, therefore, resulted in the formation of defects in the composite. With the introduction of 60 parts by weight into the epoxy urethane matrix, the tensile strength increased to 13.9 MPa as compared with 0.3 MPa for the unfilled composite. This was the result of the intermolecular interaction change in the filled biocomposite due to appearance of polymer–filler interaction, which had a positive effect on the cohesion energy of the polymer matrix. With increasing filler content in the composite to 80 parts by weight, its tensile strength decreased slightly. It was shown that the biocomposites retained good and stable physical and mechanical properties under environmental conditions under the action of some destructive factors. However, there was a significant decrease in the tensile and flexural strengths of the samples exposed to water and ground, which indicated their biodegradability.

5-15

Authors: О.І. Kuntyi, G.I. Zozulya, M.V. Shepida

This mini-review summarizes the publications of the last decade dedicated to the study of the formation of metal nanostructures by galvanic replacement reaction in a non-aqueous medium (organic solvents and ionic liquids). It is shown that among modern methods of surface modification of nanostructures, galvanic replacement reaction belongs to one of the most effective ones in terms of preparing new materials and application of metal films. However, controlled formation of nanostructures is not always possible in aqueous solutions due to the occurrence of side chemical and electrochemical processes. The latter can be prevented in non-aqueous media, making them promising in chemistry of nanomaterials. A significant difference between the formation of M1/M2 nanostructures, where either electronegative (Mg, Al, Si, Zn, Co) or electropositive (Cu, Ag) elements serve as a sacrificial surface (M1), is illustrated by the galvanic replacement reactions occurring in organic solvents (ethanol and organic aprotic solvents) and ionic liquids. The data on the influence of the nature of non-aqueous media and the basic parameters of the galvanic replacement process (solution composition, temperature and duration) on the deposits morphology and the geometry of the deposited particles are reported. It is shown that the galvanic replacement method in a non-aqueous medium promotes the controlled deposition of metallic nanoparticles on the macro- and nanosurfaces of the substrate and allows obtaining nanomaterials with predetermined functional properties.

31-37

Authors: Assaf H. Tawfeeq, Bushra B. Qassim

A simple, automated, sensitive and environmentally friendly flow-injection/merging zones technique was developed for the determination of doxycycline hyclate in raw materials and pharmaceutical formulations. This method involves the reaction of azo metol with doxycycline hyclate to produce a yellow dissolved complex with a max=445 nm. The developed technique is simply and low-cost, it provides the use of an aqueous medium that is nontoxic and causes no pollution, thereby belonging to green chemistry. The method is sensitive, precise and accurate; the limit of detection is less than 0.3 g mL–1, the relative standard deviation is less than 1.5% and the recovery is about 98%. Various chemical and physical conditions that affected the reaction have been studied. An analytical calibration curve was linear within the concentration range of 5 to 125 g mL–1. The sample throughput is about 120 samples per hour. The proposed procedure can be successfully applied to estimate the content of doxycycline hyclate. The results of determination are satisfactory as compared with those given by a reference method of British Pharmacopeia: there is no significant difference between the results obtained by both methods regarding accuracy and precision at the 95% confidence level.

43-54

Authors: A.V. Dubenko, M.V. Nikolenko, O.Yu. Vashkevich, O.S. Baskevich

A new method of leaching of altered ilmenites was developed. This method involves the use of sulfuric acid as a reaction medium for the leaching process and fluoride ions as an activator of the dissolution of a rutile fraction of the ore. The effects of the nature of fluorinating reagent, sulfuric acid concentration, process temperature and molar ratio Ti:F on the efficiency of the leaching process have been established for the first time. The best results were obtained when the leaching process was performed in the presence of sodium fluoride at the molar ratio of Ti:F=1:2. It was experimentally determined that it is not advisable to conduct the leaching at temperatures higher than 100C and by using sulfuric acid solutions with the concentrations higher than 85%, since this leads to a decrease in the leaching degree of titanium. A new kinetic equation in terms of the "compression sphere" model was suggested. This equation describes the sulfate-fluoride leaching with the participation of three reagents: rutile that is in solid state and the two are in a liquid phase (sulfuric acid and fluoride ions). Kinetic study showed that the addition of fluoride ions to the reaction medium intensifies the reaction between sulfuric acid, ilmenite and rutile by reducing the activation energy to 45 kJ mol–1. It was proposed to consider the leaching of altered ilmenites and rutile by sulfuric acid in the presence of fluoride additives as a homogeneous-heterogeneous catalytic process where fluoride ions act as a bifunctional catalyst.

60-65

Authors: S.P. Zahorulko, Farat O.K., A.V. Mazepa, S.A. Varenichenko, V.I. Markov

A limited number of publications on the chemistry of chromene-4-imine derivatives can be explained by the lack of effective methods for their synthesis. We developed a one-step method for the synthesis of 4H-chromene-4-imines by rearrangement of 1,3-benzoxazines under influence of Vilsmeier-Haack reagent. It was stated that the bromine atom at the position C-6 of the chromene cycle does not affect the rate of the rearrangement. However, the presence of an electron-accepter nitro group in the aryl substituent of the 1,3-benzoxazines requires an increased reaction time of up to 6 h and an elevated temperature of up to 110C. To continue the study of chemical transformations of the synthesized rearrangement products, the interaction between 4H-chromene-4-imine derivatives and hydroxylamine was carried out, but 4H-chromene-4-on-derivatives were formed, instead of the expected opening of chromene cycle with the formation of isooxazole derivatives. The structure of the products was confirmed by 1H NMR spectroscopy, mass spectrometry, elemental analysis and X-ray diffraction analysis.

72-79

Authors: N.I. Kobyzhcha, V.M. Holovatiuk, V.V Sukhoveev, M.V. Strilets, V.I. Kashkovsky

The paper reports the synthesis of new spirocyclic mono- and diacyl-substituted pyrimidine-2,4,6-trione derivatives by using ring-closing metathesis reactions. Initially, acylation of active N–H groups in the positions 1 and 3 by various benzoyl chlorides yields a series of respective mobenzoyl- and dibenzoyl-substituted trioxopyrimidines as a starting material for metathesis. It was experimentally established that the use of N,N-diethylaniline as a base led to monoacylated product, while the interactions of diallylpyrimidinetrione disodium salt with respective benzoyl chlorides allow obtaining disubstituted products with a high yield. The synthesized intermediates were converted into new unsaturated spirocyclic derivatives of pyrimidintrione via ring-closing metathesis reactions and with the aid of ruthenium carbene complex. It was determined that N-heterocyclic phosphine-free ruthenium carbene benzylidene Hoveyda–Grubbs catalyst and monophosphine imidazolidine-containing phenyl-indenylidene ruthenium complex are the most effective for ring-closing metathesis reaction. The structure and chemical purity of all new synthesized compounds were proved by 1H and 13C NMR spectroscopy and elemental analysis. It was experimentally established that some spiro-annulated pyrimidintrione derivatives showed a significant analgesic activity and can compete with well-known pyraolone-containing drug "analgin". It was shown that all synthesized products have a low acute toxicity and hence they are a low-toxic or non-toxic compounds.

88-95

Authors: V.I. Larin, V.V. Datsenko, L.M. Egorova

The removal of some heavy metal ions from wastewaters of electroplating production was studied. It was stated that the purification of electroplating wastewaters from heavy metal ions can be carried out via Fenton reaction by using iron(II) sulfate. The main stages of the process of removal of copper-zinc wastewaters from heavy metal ions have been defined and optimized. The key parameters for conducting the purification have been established which allow impeding the reverse dissolution of the precipitate, increasing the degree of the removal of heavy metal ions (up to 99.9%) and reducing the time required for the treatment (up to 25‒30 min). The X-ray diffraction analysis revealed the chemical composition of a poorly soluble compound formed after the precipitation of heavy metal ions (Cu(II) and Zn(II)) by NaOH solution and after its treatment with Н2О2 solution. The performance evaluation was performed for the removal of heavy metal ions from wastewaters in the form of hydroxides. It was stated that heavy metal ions can jointly precipitate and the minimal solubility of the produced metal hydroxides is observed in the рН range of 9 to 10.5. The flow chart for the removal of heavy metal ions (copper and zinc) from wastewaters of electroplating production has been developed and optimized. The proposed process involves a partial return of the used reagents to the production cycle and ensures a deep purification from copper and zinc ions.

106-114

Authors: Т.O. Nenastina, M.V. Ved', M.D. Sakhnenko, V.O. Proskurina

The mechanism and kinetics of electrolytic oxidation of ethanol on electrodes with composite electrolytic coatings were investigated. The electrocatalytic coatings based on cobalt alloys with refractory metals (Mo, W, and Zr) were deposited from pyrophosphate-citrate electrolytes using pulsed current (4 A/dm2, the pulse duration and pause duration being 2 and 10 ms, respectively). The presence of oxygen in coatings has been detected that originated from intermediate oxides of tungsten and zirconium which were captured by a metallic matrix, therefore these coatings can be considered to be composite. It was shown that the surface morphology of the obtained coatings depended on the nature and content of metallic constituents, other conditions being equal. The surface of Co–Mo–WОх і Со–Mo–ZrО2 showed a network of microcracks and some spheroidal structures with a diameter of 1–5 m could be observed. The Co–W–ZrО2 coating was uniform with evenly developed surface and the diameter of spheroids did not exceed 0.2–2.0 m. Cyclic voltammograms indicated that Co–Mo–WOx composite coatings were the most stable under the conditions of anodic polarization due to the incorporation of tungsten and molybdenum oxides into their composition. The study of the kinetics of ethanol anodic oxidation on electrodes with composite coatings revealed that some intermediate metal oxides participate in the transfer of oxygen. By comparing the values of half-peak current densities in the reaction of ethanol oxidation, we stated that the highest electrocatalytic activity among the studied composites exhibited tungsten-containing coatings.

121-127

Authors: I.V. Pylypenko, L.M. Spasonova

The work reports the method of the synthesis of inorganic composite materials based on iron oxides and montmorillonite via thermal decomposition of iron oxalate (II) particles in the interlayer space of montmorillonite. The structure of the synthesized materials was investigated by X-ray diffraction analysis and low temperature nitrogen adsorption. It is shown that the fabricated composite exhibited a high content of mesopores, which was confirmed by a larger total pore volume (up to 0.313 cm3/g), unlike the original montmorillonite (up to 0.078 cm3/g). By using X-ray fluorescence analysis, the content of iron oxide in the samples was determined which varied from 9.4 to 51%. It was found that an increase in the content of iron oxide in the samples led to the shift of the point of zero charge to a more alkaline region (pH 9.4 for the sample with the content of iron oxide of 40%). The efficiency of the synthesized materials with respect to the sorption extraction of chromium (VI) from aqueous solutions was estimated. It was shown that an increase of the iron oxide content improved the sorption properties of the materials: we observed an increase of the maximum adsorption capacity by 9 times and the selectivity by almost 6.5 times as compared with both initial montmorillonite and the samples of composites. The optimal content of iron oxide in the composite was found to be 40.2%, which provided the maximum adsorption capacity of hexavalent chromium of 62.8 mol g–1 and the value of the equilibrium constant in the Langmuir equation of 0.01832 dm3 mol–1. The results of the work show that the synthesized composites can be used as promising sorption materials for removal of anionic forms of contaminants from aqueous solutions.

134-139

Authors: A. Slipkan, D. Kytova, A. Shtemenko

The basic electrophysical properties of zirconium phosphate nanoparticles with intercalated rhenium(III) compounds and the system rhenium(III)/cis-platin were investigated. The size of the studied nanoparticles is 95–150 nm, depending on the structural type of rhenium(III) compound that was intercalated into zirconium phosphate. Transmission electron microscopy reveals the layered structure of the nanoparticles and their hexagonal shape. Zeta potential and electrophoretic activity of nanosystems in water indicate the adhesion of nanosheets, which explain the mechanism of the protective function of the intercalated substance against environmental influences. This behavior of the nanoparticles explains the mechanism of the effect of pH of the medium on the process of release of the active substance from the interlayer space of zirconium phosphate. Given the features of the structure of zirconium phosphate, the phosphate groups of which are directed on both sides relative to the plane of the layer, the intercalation of the rhenium(III) compound takes place both in the interlayer space of the nanoparticles and on its surface. The content of rhenium(III) compound and cis-platin on the surface of the studied nanosystems was determined by energy dispersive X-ray analysis. Thus, the rhenium(III) content on the sample surface ranged from 4% to 12%, the cis-platin content ranged from 2% to 5%, depending on the composition of the sample.

148-156

Authors: V.V. Solovey, M.M. Zipunnikov, V.B. Poda, І.О. Vorobjova

We considered the process of hydrogen generation from water by using the alloys based on aluminium and silicon with the alloying additions of alkaline earth metals. The degree of completeness of the interaction between the above alloys and NaOH solution (10–13.3%) was determined for the range of initial temperatures of 90C to 130C. The required aluminium content in the ferro-silicon-aluminium alloys should be about 25–30% to intensify the hydrogen generation process in a laboratory reactor with a volume of 1.1310–3 m3. The reactions of ferro-silicon and ferro-silicon-aluminium alloys with water were investigated in an AVG-45 autonomous balloon-type gas generator. The Gibbs energy value was calculated taking into account the influence of pressure changes in the gas generator. Recommendations have been developed to apply a silicone method of hydrogen generation in the hydrogen gas generators using aluminium-silicon alloys. The interaction of aluminium–sodium hydride composites with the NaH content of 23 wt.% and 50 wt.% as well as the samples of sodium aluminium hydride (NaAlH4) with water was studied to use them in the hydrogen gas generators. The procedure of hydrogen generation by means of hydro-reactive substances was adopted as a basic one to use in the hydrogen generation systems and in the developed system of hydrogen storage and hydrogen supply in experimental samples of the autonomous lifting installations.

163-171

Authors: Z.F. Tomashyk, I.O. Shelyuk, M.V. Chayka, V.M. Tomashyk

The process of chemical dissolution of the GaAs, InAs, InAs (Sn), GaSb and InSb single crystals in aqueous solution of H2O2–HBr–tartaric acid has been investigated in reproducible hydrodynamics conditions for the first time. The dependences "etchant concentration vs. etching rate" have been plotted and the concentration limits of the regions corresponding to polishing, selective and non-polishing etching solutions have been determined. It was established that an increase in the content of tartaric acid promoted a decrease in the dissolution rate of semiconductors. The differences between the chemical dissolution of arsenides and antimonides of gallium and indium were established. The influence of impurities on the chemical etching of III–V semiconductor compounds was investigated. The dependence of the dissolution rate on the mixing rate and etching temperature were established and the rate-determining steps of the dissolution process were determined. The polished surface of single crystals after chemical treatment was characterized by metallographic analysis and profilometry technique. The polishing etchants composition and the condition of chemical-dynamic polishing process and selective etching of these semiconductors were optimized.

177-186

Authors: М.О. Chaban, L.M. Rozhdestvenska, О.V. Palchik

The work is devoted to the development of a sorption method for the extraction of lithium from seawater using oxides of polyvalent metals obtained in the form of large granules. The initial oxides of Ti and Ti–Mn contained a phase of lithium spinel, the sorbents were previously converted into hydrogen form. Sorption of Li+ ions under dynamic conditions was investigated using a model solution containing the following alkali metal ions (mmoldm–3): Li+ 0.014, Na+ 252.1, and K+ 5.4. The ratio of Li+, Na+ and K+ contents in the sorbents was found to be 1:11:1 (in TiO2) and 1:4:1 (in Ti–Mn), respectively. These sorbents could be regenerated by NaOH solution (partially) or by acids (completely); they did not dissolve in 1 M HNO3 at 20–45C. The effects of sorbent dosage and concentration of HNO3 solution on desorption of Li+ ions were studied. Several cycles of sorption–desorption were carried out for titanium-manganese sorbent without renewal of the regenerating solution. It was shown that the sorption capacity remains constant for 5 cycles; then it is decreased and can be recovered by using a fresh regenerating solution. The treatment of the obtained concentrate involves bubbling ammonia through the solution, precipitation of LiCO3 and formation of a mixture of nitrates and carbonates of potassium and sodium that can be further used as fertilizer. It is proposed to integrate the lithium extraction into the reverse osmotic desalination of seawater: the sorption process implies its preliminary softening.

194-200

Authors: O.V. Chudinovych, O.I. Bykov

Phase equilibria in the La2O3–Y2O3–Er2O3 ternary system at the temperature of 1500C have been investigated for the first time by means of XRD and X-ray microprobe analysis. The samples of different compositions were prepared from nitrate acid solutions by evaporation, drying and calcinations at the temperatures of 1100 and 1500C. The XRD analysis of the powders (CuK irradiation) was performed at ambient temperature. It was stated that the solid solutions based on various polymorphous forms of constituent phases and one-ordered phase with a structure of the perovskite-type of LaYO3 and LaErO3 were formed in the system under consideration. The boundaries of mutual solubility and concentration dependences of the lattice parameters for all phases have been determined. The isothermal section of the La2O3–Y2O3–Er2O3 phase diagrams at 1500C is characterized by the existence of one three-phase (B+C+R), four two-phase (A+B, B+R, C+R, and A+R) and four single-phase [A-La2O3, B-La2O3, R, and C-Y2O3(Er2O3)] regions. The solid solutions are formed via isovalent substitution. The stability of ordered phases and solid solutions are determined by a dimensional factor. An ordered R-phase in the ternary system exists in the wider range of concentrations than in the binary systems.