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

5-19

Authors: L.O. Snizhko, V.O. Holovenko, V.I. Оvcharenko, O.O. Kalinichenko, K.V. Roienko, V.V. Bezditnyi

The review provides the main patterns of diesel soot oxidation in the engine. The technology of producing catalysts for automotive filters by plasma electrolytic synthesis is considered. It is shown that the catalytic mass can be deposited on oxide porous layers formed from aqueous solutions on metal structures of any shape. Two following methods of active mass deposition are considered: sequential impregnation of the oxide matrix in solutions of active metals salts and direct deposition of catalytically active elements during the electrolysis. Methods of testing catalysts in the reactions of CO oxidation and combustion of diesel soot using direct reactor and thermogravimetric analysis are described. The kinetics of carbon oxidation on the resulting coatings is considered; the activation energy of the process is calculated. It is shown that, in contrast to the impregnation method which allows introducing active cationic components (Cu2+, Mn4+, Co4+, Mo4+), the plasma electrolytic synthesis method is limited only by the possibility of introducing anionic components (WO42–, MnO4–, VO3–, SbO2–, МоО42–). It is established that the resulting coatings reduce the combustion temperature of diesel soot in the range of 160–180°C. The possibility of simultaneous deposition of combined oxides on the metal surface, for example, nAl2O3(TiO2)/W(Mo)Ox, is shown.

26-33

Authors: R.D. Apostolova, E.M. Shembel

It was stated that the natural FeS2-pyrite (without any additives of electroconductive filler and binder) in the form of a thin-film electrode in a medium of alkyl carbonate electrolyte (ethylene carbonate, dimethyl carbonate, and LiPF6) showed an electrochemical activity in the deintercalation reaction with lithium at about 2.4 V vs. Li/Li+ reference electrode. This reaction was associated with the distortion of FeS2 due to the dissolution of generated inactive lithium polysulfides in the electrolyte, which, in turn, resulted in a loss of the discharge capacity of lithium accumulator during cycling. A reversal cycling of the investigated FeS2-pyrite in an alkyl carbonate medium occurred in the potential range of 2.1 to 1.1 V. In ethers of dioxolan and tetrahydrofuran THF with LiCF3SO3 salt in a polymer matrix poly (vinylidene fluoride-co-chlorotrifluoroethylene) (PVdF-CTFE), the electrochemically produced FeS2-composite did not exhibit an undesirable electrochemical activity at the potentials near 2.4 V in deintercalation process with lithium. This phenomenon was caused by a triple effect of ethereal solvents (dioxolan and tetrahydrofuran), lithium salt (LiCF3SO3) and polymer matrix (PVdF-CTFE). The effective diffusion coefficient of lithium ions for the electrochemically produced FeS2-composite was determined by the method of cyclic voltammetry (5.5810–11 cm2 s–1); it coincided with the data obtained by galvanostatic cycling. Thus, an electrochemically fabricated FeS2-composite can be successfully used in the lithium/sulfur accumulators.

46-52

Authors: О.F. Bulat, S.L. Davydov, S.O. Oparin, L.T. Kholyavchenko, E.S. Klyuev

The article addresses an actual problem associated with the development of methods for processing environmentally "dirty" carbon-containing raw materials, including coal, with the aim of preparing them for safe use in industry as an energy carrier that is an alternative to oil and gas. The article presents the results of theoretical and experimental studies of the process of plasma transformations of carbon-containing media. The prospects of a further development of the allothermic method of converting ecologically problematic raw materials into gas using the energy of vapor plasma are shown. This method involves the processes of plasma formation that combine thermal transformations and the generation of an oxidizing agent from water. The influence of the temperature of vapor-plasma on the characteristics of the resulting gas phase is established taking into account the elemental composition of a medium. The energy balance for the process of vapor-plasma transformations of carbon-containing media into gas is made up. It is shown that vapor-plasma allothermic processes are universal to treat raw materials; they are environmentally safe and low metal consuming. Therefore, these processes can be the basis for the further development of technologies for thermal transformations of carbon-containing media, including solid waste.

59-68

Authors: A.M. Grinko, A.V. Brichka, О.М. Bakalinska, O.I. Oranska, М.Т. Каrtel

A number of kaolin-based nanomaterials decorated with CeO2 were synthesized by the precipitation method from aqueous solutions of cerium nitrate, without stabilizers at room temperature, and their properties were characterized. The amount of nanoceria deposited in nanomaterials was 2.76–7.37%, and their size varied from 5.6 nm to 10.4 nm. X-ray diffraction analysis of the samples showed that cerium dioxide has a cubic structure. IR spectroscopy confirmed that a chemical interaction between the modifier and the matrix (i.e. the formation of a chemical bond) cannot be detected. The Ce4+/Ce3+ ratio in nanocomposites was estimated from UV-spectra of diffuse reflectance, it varied in the range of 0.98 to 2.88. By calculating the affinity constant from kinetic data in the framework of enzymatic reactions concept, the catalytic activity of the synthesized materials and kaolin in the model reaction of hydrogen peroxide decomposition was determined in the pH range of 8.5–10.5 and compared with the catalase enzyme and commercial nano-sized CeO2. The pH dependence of the nanocomposites activity was shown to be extreme with maxima at pH 10.0. The activation energy of the reaction of hydrogen peroxide decomposition on the studied catalysts was determined for the temperature range of 20C to 40C at pH 10.0. It was found that the catalytic activity of nanocomposites increased and the activation energy decreased with an increase in the decorator content at a constant pH. An analysis of the factors that determine the activity of nanoceria in the nanocomposites showed that an increase in the dispersion of nanocrystallites and the relative content of Ce3+ ions on their surface resulted in the improvement in the catalytic activity of nanomaterials.

88-95

Authors: V.F. Kirianchuk, Z.I. Demchuk, B.S. Domnich, A.M. Kohut, O.H. Budishevska, A.S. Voronov, S.A. Voronov

The depletion of fossil fuel feedstock and the deterioration of the planet environment stimulate the search for alternative renewable raw materials to synthesize monomers and polymers. A promising renewable resource for the synthesis of the polymers is a wide range of plant oils. In this study, we have synthesized the monomer via transesterification of triglycerides of high oleic sunflower oil by using N-(hydroxyethyl)acrylamide. The presence of the acryloylamide moiety and oleic acid acyl fragment in the high oleic sunflower oil-based monomer molecule was confirmed by means of infrared and nuclear magnetic resonance spectroscopies. Then, the plant oil-based homopolymers with an average molecular weight of (19–21)103 have been synthesized using free radical polymerization mechanism in a toluene solution (75C, azobisisobutyronitrile as an initiator). Stable latexes with unimodal particle size distribution were obtained using miniemulsion polymerization (with an average molecular weight of latex polymer of 33103). Based on the established polymerizability of the synthesized monomer, we showed the synthesized monomer can be copolymerized with commercial monomers to form copolymers with adjustable physical-mechanical properties for the production of hydrophobic coatings, adhesives, surfactants, cosmetic products, composites, etc.

101-107

Authors: O.O. Коrolev, O.S. Bondar, I.M. Kurmakova, O.I. Syza

The influence of the degree of protonation of the molecule on inhibitory action on acid corrosion of a structural steel by secondary amines with triazoloazepinmethyl and aryl radicals was considered in this work. The anticorrosive inhibitors were prepared via interaction between 7-metoxy-3,4,5,6-tetrahydro-2Н-azepine and hydrazides of substituted N-arylaminoacetic acids. The results of quantum-chemical calculations showed that the form of the existence of molecules in a solution for the investigated secondary amines with different radicals (–Н, –F, –Cl, –I) in benzene ring depends on pH of a medium. The most pronounced influence is observed within the pH range of 0 to 3. High inhibition efficiency (more than 85% at a concentration of 1 mmol/L) of these compounds in the sulfate acid environment is provided by the predominance of molecules that are protonated by a nitrogen atom of triazole cycle. This effect is observed for all investigated derivatives in 0.1 M sulfuric acid solution (pH 0.7) and for the compounds with para-chlorophenyl and para-iodophenyl substituents in 0.5 M sulfuric acid solution (pH 0). Based on the results of polarization measurements, it was concluded that the highest inhibition efficiency (96.09% in 0.1 М Н2SO4) of the compound with para-iodophenyl radical is explained by its specific adsorption with the formation of a stabilized complex with charge transfer from the adsorbate to metal. This causes the formation of a strong protective inhibitor layer on the steel surface. The protective effect is reduced when the quantity of molecules protonated by two nitrogen atoms in solutions increases, which occurs with increasing either the acidity of the medium or the unprotonated forms with increasing pH, which is explained by hindering the adsorption of the secondary amines under study.

116-121

Authors: E.S. Mammadova, Z.Ch. Salaeva, A.E. Huseinova, G.A. Mammadaliev

The paper reports the results of experiments on the development of production of alkylphenols using the method of thermal alkylation of phenol with a-olefins. The influence of technological parameters, such as temperature, pressure, reaction time and molar ratio of reagents, was studied. An increase in the reaction temperature and molar ratio of phenol:olefin positively affects the degree of conversion of olefins, which reaches a maximum value of 85% at 4250C and molar ratio of fenol:olefin of 5:1. However, an increase in the reaction temperature higher than 4000C negatively affects the selectivity of the process for "extremely substituted" alkylphenols, which decreases from 97% to 76% at 4000C and 4250C, respectively. The optimum conditions of the process were found as follows: the reaction temperature of 4000C, the pressure of 6.0 MPa, the molar ratio of phenol:olefins=4:1 and the reaction time of 1 h. Under these conditions, the degree of conversion of olefins and the selectivity with respect to monoalkyphenol are equal to 50% and 90%, respectively. The possibility of full isomerization of alkylphenols ethers into relevant alkylfenols on the catalyst KU-2 was shown. Prepared alkylphenols were tested as a basis for the production of surfactants. Thermal alkylphenols were compared with acidic samples of alkylphenols. It was shown that alkylphenols prepared by thermal alkylation process allow producing surfactants, which exhibit high surface-active properties with reference to the interfacial tension of solutions "surfactants–kerosene". Based on the obtained results, the flowsheet of the thermal alkylation process of phenol with a-olefins was proposed.

128-133

Authors: P.О. Nekrasov, О.M. Gudz, О.P. Nekrasov, T.O. Berezka

Currently, the vast majority of solid fats, which are used as formula components of food products, are produced in Ukraine by partial hydrogenation. This method of fats modification leads to the formation of a significant amount of trans-isomers of fatty acids, which negatively affects the human body. It is known that the increased content of these isomers in the composition of fat products results in an increased risk of developing cardiovascular and metabolic diseases. In particular, the action of high-density lipoproteins is blocked, the deposition of cholesterol plaques on the walls of human blood vessels is initiated, and the development of atherosclerosis is provoked. We suggest resolving this problem by using interesterification of fats under the action of lipases, which has some advantages as compared with traditional technology. For instance, alkaline agents will not be used for catalysis, the reaction products will not be contaminated with catalysts, soaps will not be formed as by-products, the temperature of the process will be almost halved, and the organization of production will be less complicated and cheaper. The purpose of the work was to determine the rational parameters of the interesterification reaction aimed at the synthesis of fat systems with a minimum content of trans-isomers. The research objective was achieved by using the response surface methodology. The kinetics of reaction was studied by pulsed nuclear magnetic resonance. The processing and analysis of experimental data was performed by means of the Statistica 10 package. As a result of investigations, a mathematical model was developed that allows predicting the degree of conversion of starting materials into reaction products based on the data on the conditions of the interesterification process. Rational values of the main parameters for the synthesis of fatty systems with a minimum content of trans-isomers of fatty acids were specified. The obtained results can serve as a scientific basis for the development of technology for the production of fat systems with improved quality and safety characteristics.

140-147

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

Microporous carbon sorbents are widely used in the purification of liquids and gases. A new modern direction in the development of carbonaceous materials is production of mesoporous carbon with varied properties. The aim of this work was to evaluate the activity of metal-containing mesoporous carbon samples with insignificant microporosity in the conversion of n-hexane. Mesoporous carbon was prepared by template synthesis using silica gel and furfural alcohol. In order to reduce the proportion of micropores in material, the process was carried out in two stages of additional saturation with furfural alcohol. The samples based on mesoporous carbon with nickel, palladium and two metals simultaneously were synthesized. By means of transmission electron microscopy, the size of metal particles on the surface of samples was determined. It was 2–4 nm for nickel-containing sample, while it was 3.5–6 nm with inclusion of individual particles of up to 13 nm for palladium-containing samples. Low-temperature nitrogen adsorption technique showed that the modification with palladium resulted in the formation of secondary mesoporosity. The starting carbonaceous material and nickel-containing sample were found to be inactive in the micropulse conversion of n-hexane. At the same time, the process proceeded over palladium-containing samples in the direction of cracking, aromatization and isomerization of n-hexane, the product yields at 400–425C being equal to 18–45%, 15–16% and 7–9%, respectively.

154-161

Authors: L.M. Rozhdestvenska, O.I. V'yunov, L.N. Ponomarova, A.V. Bilduykevich, T.V. Plisko, Y.G. Zmievskii, V.D. Ivchenko

Organic-inorganic membranes containing the nanoparticles of hydrated zirconium dioxide and BaFe12O19 magnetic nanoparticles were prepared. The nanoparticles were inserted into polymer matrices. Ultrafiltration membranes were used as a polymer substrate. These materials consist of macroporous layer (non-woven polyester) and ultrathin active layer (polysulfone or polyacrylonitrile). Morphology of the membranes was investigated using scanning electron microscopy. It was established that inorganic nanoparticles form aggregates, a size of which is up to 20 nm in active layer and up to 2 m in macroporous fibrous support. Larger aggregates are formed in the absence of a magnetic constituent (up to 5 m). Fractal analysis showed the diffusion-limited aggregation model of particle formation. The inorganic particles form a "secondary active layer" inside the polymer pores: this layer determines water flux and rejection ability of the membrane. A thinner "secondary active layer" is formed in the polymer matrix containing smaller pores. The prepared membranes were tested for filtration of sugar beet juice. The modification was shown to improve the ability of the membranes to reject proteins. Due to smaller particle size, the membrane containing BaFe12O19 shows the liquid flux of 4.310–7–5.710–7 m3m–2s–1 at 2 bar and the rejection towards vegetable protein of 55–87%. Regarding the membranes that do not include magnetic nanoparticles, these values are 3.810–7–5.510–7 m3m–2s–1and 38–77%, respectively.

170-177

Authors: O.V. Savvova, V.M. Shimon, O.V. Babich, M.V. Shimon, N.O. Ashukina, A.A. Sherehii

Prospective trends in the development of glass-ceramic materials for bone endoprosthesis replacement were analyzed. The glass-ceramic materials based on calcium phosphate silicate glasses containing modifying components (MgO, CoO, V2O5, SrO, Cu2O, MoO3 and La2O3) were suggested. The period of resorption of the developed glass-ceramic materials was estimated and the optimal leaching parameters with respect to calcium cations, phosphate groups and pH of the solution were established in vitro to form an apatite-like layer on the surface of calcium-phosphate-silicate glass-ceramic materials in vivo. The reorganization of bone regenerate was revealed, which is an indicator of bone tissue mineralization in the structure of the developed glass-ceramic material after a 30-day exposure in vivo. The use of new types of biocompatible bone implants based on the developed bioactive glass-ceramic materials will significantly reduce the duration of the rehabilitation period in endoprosthesis replacement and increase the service life of the product under load on bone tissue.

183-188

Authors: N.V. Simurova, O.I. Maiboroda, I.V. Popova

1,3,4-Oxadiazoles are five-membered heterocyclic molecules that proved to be biologically active agents with a wide range of activities. They used as medicinal agents, insecticides, fluorescent materials, etc. At the same time, it is important to design the compounds, which, along with the oxadiazole ring, contain other groups that may affect the biological properties of a molecule, in particular, amide groups, which show high pesticidal activity. In this work, we developed a convenient preparative method for the synthesis of 2-furyl (thienyl)-5-chloromethyl-1,3,4-oxathiazoles which allows producing significant quantities of target substances with a high yields. The possibility of their further functionalization due to the active chloromethyl group is shown. Via the interaction of starting 2-furyl/thienyl-5-chloromethyl-1,3,4-oxathiazole with primary amines followed by the acylation with 4-chloro-2-pentenoic acid, a number of new N-alkyl-N-[5-furyl/thienyl-1,3,4-oxadiazolyl]-2-pentenamides were synthesized which contain an unsaturated amide fragment, along with 1,3,4-oxadiazole ring. The synthesized products were identified by 1H NMR spectroscopy and their composition was confirmed by elemental analysis. The results of our study can be used in synthetic practice and the synthesized compounds should be further investigated in terms of their possible biological activity, particularly as insecticides.

197-201

Authors: K.V. Terebilenko, O.V. Petrenko, I.I. Tokmenko, M.S. Slobodyanik

For the binary system хNa0.5Bi0.5MoO4–(1–х)BiVO4, an ideal isomorphism was established within x=0.1–0.9 leading to the formation of solid solutions of the total composition Na0.5xBi1–0.5x(MoxV1–x)O4, which belongs to the structural type of scheelite and crystallizes in a tetragonal system, space group I41/a. The use of the solid-state approach allowed producing powdered samples of all the representatives of solid solutions with a grain size of 0.5 to 5.0 m. An increase in x value leads to an increase in the grain size up to the average value of 5 m according to the data of scanning electron microscopy. The results of ІR spectroscopy and powder X-ray diffraction method revealed that molybdenum and vanadium occupy a single crystallographic position with a statistical distribution for x=0.1–0.9, while the symmetry of the framework does not change. The charge compensation is realized due to the proportional substitution of bismuth in the polyhedra with the mixed (Na/Bi)O8 polyhedra. As the molybdenum content in the solid solutions increases, there is a proportional increase in the volume of the unit cell of the scheelite framework illustrating the Vegard rule for the ideal isomorphism. According to the data of diffuse reflection spectroscopy, it was shown that there is an increase in the band gap values from 2.28 to 2.67 eV for the semiconductors obtained when the value of substitution (x) increases. This allows considering them as promising photocatalysts for water splitting reaction.

210-214

Authors: A.N. Chebotarev, D.V. Snigur, T.M. Shcherbakova, E.M. Guzenko, E.M. Zhukovetska

The method of indirect sorption-spectrophotometric determination of nonionic surfactants was developed. The proposed method is based on the sorption of nonionic surfactants by silica L5/40 followed by the formation of complex compound with barium cations on silica surface and the appearance of an ionic associate of this complex compound with bromothymol blue dye. The conditions of the sorption of nonionic surfactants (synthanol DT-7) were optimized. It was stated that the maximum recovery occurs in a slightly acidic medium at pH 3 near the silica zero charge point, the mass of the sorbent sample and the contact time being 0.1 g and 30 min, respectively. After the treatment of the obtained concentrate with solutions of barium chloride (510–4 mol L–1) and bromothymol blue (110–4 mol L–1), an ionic pair is formed which is firmly held on the silica surface, and the light absorption of the residual amount of the dye is inversely proportional to the content of synthanol DT-7. The calibration graph is linear in the range of the synthanol DT-7 concentrations of 1.510–5 to 1.510–4 mol L–1. For a sorption volume of 50 mL, the limit of detection and limit of quantification are equal to 4.310–6 and 1.510–5 mol L–1, respectively. It was established that the variation of total mineralization from 2 to 12 g L–1 does not lead to significant changes in the intensity of light absorption in determining the content of synthanol DT-7. The developed method was successfully tested in the analysis of natural and mineral waters with different mineralization. The relative standard deviation did not exceed 5.5%.

4-29

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

The development of the processes of chromium electrodeposition from electrolytes based on trivalent chromium compounds is an urgent problem in modern applied electrochemistry. The topicality of this issue is associated with the search for an alternative to the chromium deposition processes that involve solutions of extremely hazardous and toxic compounds of hexavalent chromium. The literature data on the main trends of the development of chromium deposition processes from Cr(III)-based electrolytes are summarized in this review. The numerous data on the kinetics and mechanism of the step-wise discharge of trivalent chromium ions are analyzed. The effect of organic additives on the chromium electrodeposition is characterized. The results of the studies devoted to the influence of electrolysis conditions and electrolyte compositions on the current efficiency of chromium deposition reaction, the microstructure and the main physicochemical properties of the obtained coatings are summarized. The chromium deposition processes with the use of environmentally safe Cr(III)-based electrolytes are shown to exceed those based on Cr(VI) compounds with respect to the current efficiency, covering power and some properties of electrodeposits (corrosion and wear resistances, microhardness, etc.). It is noted that the production of high-quality thick chromium layers (with the thickness of no less than several tens micrometers) from electrolytes containing Cr(III) salts remains an important task in modern surface engineering. Much attention is being paid to the development of chromium deposition processes which are based on the ionic liquids and, especially, on their new generation, deep eutectic solvents.

36-43

Authors: D. Girenko, O. Shmychkova, A. Velichenko

An increase in the current efficiency of hypochlorite up to 80–85% and a possible decrease in the current efficiency of chlorate up to 5–8% are observed if the electrolysis of NaCl occurs on a pre-reduced Ti/Pt electrode surface. However, the time of the electrolysis on a reduced surface is limited and significantly decreases with increasing current density. The need for the reduction of the surface every time before the electrolysis almost negates the practical value of the above results. The duration of the transition from the reduced surface to the oxidized state can be appreciably decreased in low-concentrated solutions of NaCl (0.15–0.45 M NaCl solutions are commonly used in practice to prepare hypochlorite solutions by direct membraneless electrolysis). For instance, the duration of the transition is 1200 s and only 80 s in 0.3 M and in 0.15 M solutions, respectively (at 20 mA cm–2). Moreover, it becomes possible to refuse the procedure of the pre-treatment of the anode and conduct the electrolysis at any duration on the reduced surface under current reversal conditions. If the electrolysis of 0.15 M NaCl is performed in a "usual" regime at 20–40 mA cm–2, then the current efficiency of hypochlorite does not exceed 26% and the current efficiency of chlorate is at least 21%. It is shown that carrying out the electrolysis under current reversal conditions allows increasing the current efficiency of hypochlorite up to 39% while reducing the current efficiency of chlorate to 5%. An increase in the concentration of NaCl to 0.3 M improves the performance of reverse electrolysis even more significantly. In this case, the current efficiency of ClO– formation increases to 78% and the current efficiency of ClO3– formation decreases to 2%.

52-59

Authors: A.V. Zaichuk, A.A. Amelina, Y.S. Khomenko, A.S. Baskevich, Y.R. Kalishenko

Heat-resistant ceramics of -eucryptite composition was synthesized in the current work. To this end, the method of ceramics production was combined with the principle of reactive formation of the material structure. Taking into account the calculated data about the compositions of eutectics and temperature of their melting in the specific binary systems Li2O2SiO2–Li2OАl2О32SiO2 and Li2O2SiO2–Li2OАl2О34SiO2, a comparatively low-melting glass was developed in the system Li2O–Аl2О3–SiO2 (with a melting temperature of 1250С). Its function in the composition consists in the intensification of the processes associated with the formation of the crystalline phase of -eucryptite and sintering of the ceramic material as a whole. Based on the results of experimental study, we concluded that the duration and temperature of sintering of ceramics directly determine its microstructure and physicotechnical properties. In order to achieve the complex of the highest indices, the firing of eucryptite ceramics should be performed at the temperature of 1350С with the isothermal time of 3 h. -eucryptite phase is formed as the distinct prismatic crystals of hexagonal shape with a size of 4–7 m. The developed composition of eucryptite ceramics allows obtaining the products or individual elements with varying complexity of shapes, which significantly reduces the amount of rejects.

67-72

Authors: N.V. Kozak, T.A. Shantalii

The effect of the structure and content of inorganic component on the permeability of nitroxyl paramagnetic probe into polyimide-based organic-inorganic composites was investigated using the method of electron paramagnetic resonance and the introduction of the probe by different methods. It was shown that changes of the nature, ratio and content of the inorganic components allow regulating the permeability of the matrix. The diffusion of a probe from saturated vapor to samples sharply reduces the permeability in the presence of the inorganic phase, this indicates the compaction of the organic component. The magnitude of such a decrease does not correlate with the content of the inorganic phase. However, the use of a solvent for the introduction of a probe causes an increase in permeability of composites as compared with the initial polyimide and indicates the loosening of the organic component. The fact observed can be due to the redistribution of intermolecular bonds and enhanced mobility of macrochains in a polyimide matrix in the presence of a solvent. An increased permeability is observed for the composites with an excess of ethoxysilane. It is maximal for a sample with the content of the inorganic component of 5%.

82-92

Authors: V.V. Mischenchuk, M.M. Tkachuk, V.D. Yuzkova, A.Ya. Velyka, O.I. Panimarchuk, N.V. Panasenko, I.V. Diichuk

This article describes electrochemical systems in which the electrode processes proceed on a rotating disk electrode at low ionic strength of the solution, thus, there is an influence of the double electric layer structure on the electrochemical kinetics. We analyze the influence of the system parameters (the potential, the diffuse layer thickness, the solution ionic strength, the kinetic parameters of the electrode reaction and the charge of the electroactive species) and the reaction plane position both on the deviation from the Boltzmann distribution of the concentration of the electroactive species in the diffuse layer and on the errors in the steady-state voltammetric determination of the electrode reaction kinetic parameters arising due to neglecting the nonequilibrium of a diffuse layer. Two regions of the deviations from the equilibrium Boltzmann distribution for the electroactive species are detected at the both directions from the zero charge potential for the system with anion electroreduction/cation electrooxidation, while it is observed only one region of the deviations for the systems with electroreduction of cations/electrooxidation of anions. The different manifestation of the diffuse layer nonequilibrium in the two regions at the both sides of the zero charge potential is discussed in the paper. In particular, the nonequilibrium appears within the reaction layer in the immediate proximity to the electrode surface for the systems with electrooxidation of anions in the region of more negative potentials (with respect to the zero charge potential), whereas the nonequilibrium manifests itself throughout the diffuse layer for more positive potentials (with respect to the zero charge potential). This results in different sensitivity of the calculated kinetic parameters with reference to the reaction plane position and taking into account the reaction layer. The results obtained in this study can be used for theoretical interpretation of steady-state and unsteady state methods of electrochemical analysis as well as for the simulation of steady-state and unsteady state macrokinetics on a rotating disk electrode in the solutions of surface-inactive electrolytes at low ionic strength.

103-111

Authors: L.M. Soldatkina, M.A. Zavrichko

Modification of different agro-industrial plant waste by surfactants is one of the feasible ways to increase their adsorption capacity towards dyes. The present work represents the results of a multifactor experiment and the effects of modification factors of agro-industrial plant waste (barley straw and corn stalks) by a cationic surfactant (hexadecylpyridinium bromide) on the adsorption properties of the modified agro-industrial plant materials towards an anionic dye (Acid Red). The following independent modification factors were selected: NaOH concentration, mass ratio of hexadecylpyridinium bromide to agro-industrial plant waste, time and temperature of modification. The response function was the percentage removal of the anionic dye from aqueous solutions, which was the average of the results of two parallel series of adsorption experiments. Central composite design was carried out with all possible combinations of independent factors at five levels: –2; –1; 0; +1; +2. Modified barley straw and modified corn stalks (at 31 samples of the each plant waste) were synthesized using various modification conditions. After statistical processing of the experimental data, second-order regression equations were obtained that adequately describe the dependences of the percentage removal of the anionic dye on the main modification factors of barley straw and corn stalks. At optimum modification conditions of barley straw and corn stalks, the adsorption removal of Acid Red was high (96–97%). The optimal values of the modification factors are as follows: the treatment of barley straw and corn stalks should be performed by using 75 mM NaOH, the mass ratio of hexadecylpyridinium bromide to agro-industrial plant waste should be equal to 0.02, and the duration of modification should be 26 h at 298 K.

118-124

Authors: Y.A. Titov, N.M. Belyavina, M.S. Slobodyanik, V.V. Chumak, O.I. Nakonechna

The conditions of isovalent substitution of scandium atoms for indium atoms in B position of the SrLa2Sc2O7 two-slab perovskite structure of the SrLa2Sc2-xInxO7 type (0x0.4) are determined by X-ray powder diffraction methods. A destruction of the two-slab structure and formation of the second phase with the rhombic LaInO3 structure, which is dominant at x=0.8–2.0, are observed at a further increase of the indium atoms content in the SrLa2Sc2–xInxO7 phases. Orthorhombic crystal structure (Fmmm space group) of the SrLa2Sc2–xInxO7 phases with the scandium atoms substitution degrees of 0.2 and 0.4 is determined by the Rietveld procedure. The SrLa2Sc2-xInxO7 crystal structure is formed by two-dimensional (infinite in the XY plane) perovskite-like blocks, which consists of two slabs of (Sc,In)O6 deformed octahedra. The (Sc,In)O6 octahedra are connected only by vertices, and each (Sc,In)O6 octahedron has five common vertices with the adjacent octahedra of the same block. There is no direct connection between the (Sc,In)O6 octahedra of adjacent perovskite-like blocks in the SrLa2Sc2–xInxO7 slab structure. Adjacent blocks are separated by a slab of (Sr,La)2O9 polyhedra and are held together by means of –O–(Sr, La)2–O– bonds. The eight oxygen atoms of the (Sr,La)2O9 polyhedron belong to the same block as the (Sr,La)2 atoms and the one oxygen atom belongs to the neighboring block. Coordination number of the (Sr,La)1 intrablock atoms is equal to 12, and their coordination polyhedron is a deformed cuboctahedron. The distribution of strontium and lanthanum atoms over the SrLa2Sc2–xInxO7 structure positions has a partially ordered character with the predominant localization of strontium atoms in the intrablock cuboctahedral voids of the perovskite-like block. Analysis of the structural parameters of the SrLa2Sc2–xInxO7 phases shows that a gradual decrease in the length of the(Sr,La)2–O2 interblock bonds (from 0.222(2) nm (x=0) to 0.213(1) nm (x=0.4)) and an increase in the degree of deformation of the (Sr,La)2O9 interblock polyhedra (from 6810–4 (х=0) to 9510–4 (х=0.4)) take place with the isovalent substitution of scandium atoms for large indium atoms in the slab structure of the SrLa2Sc2–xInxO7. Reducing the perovskite-like blocks interval makes a two-dimensional slab structure closer to the structure of a three-dimensional perovskite, and an increase in the deformation degree of the (Sr,La)2О9 interblock polyhedra leads to an increase in the tension of the interblock space. These changes result in destabilization and destruction of the slab perovskite-like structure of the SrLa2Sc2–xInxO7 phases, limit the solid solutions range and cause the absence of SrLa2In2O7 indate.

134-140

Authors: N.F. Fed'ko, V.F. Anikin, V.V. Veduta, D.O. Laskorunska

The reaction of 4,5-dihalogeno- and 4,5-dinitrosubstituted 1,8-naphthalic anhydrides with ortho-phenylenediamine leading to the formation of 3,4-disubstituted benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-ones was investigated. The initial 4,5-disubstituted naphthalic anhydrides were synthesized by the oxidation of the corresponding 5,6-disubstituted acenaphthenes with sodium dichromate in anhydrous acetic acid. It was established that significant amounts of by-product of substitution of halogen atom or nitro group by arylamino group were observed when performing the reaction of 4,5-disubstituted naphthalic anhydrides with o-phenylenediamine in chlorobenzene, dimethyl sulfoxide, dimethylformamide or ethanol, whereas the use of acetic acid as a solvent allowed obtaining 3,4-disubstituted benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-ones without by-products with yields of 90–95%. It was shown that halogen atoms or nitro groups in the synthesized compounds can be substituted by oxygen- and nitrogen containing fragments leading to luminescent compounds with longer wavelength of emission maxima. The structure of the obtained compounds was confirmed by elemental analysis, mass spectrometry, IR and 1H NMR spectroscopies. The absorption and luminescence maxima of 3,4-disubstituted benzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-ones were shifted to the long-wave region of the spectrum by 15–30 nm, and the molar absorption coefficient was one and a half times more than for the corresponding monosubstituted derivatives.

148-154

Authors: K.S. Yutilova, E.A. Bakhalova, E.N. Shved, N.S. Martseniuk, L.S. Marchuk

Acidolysis of 2-(chloromethyl)oxirane (epichlorohydrin) by acetic and benzoic acids in the presence of tetraalkylammonium halides in binary solvent epichlorohydrin:tetrahydrofuran (1:1 by volume) is investigated by the methods of chemical kinetics, computer modeling and NMR spectroscopy. It is found that this is a zero-order reaction with respect to the acid and a first-order one with respect to the catalyst. The products of the reaction are chlorohydrin esters with "normal" (n-P) and "abnormal" (a-P) structures. It is determined that the reaction rate depends on both the nature and structure of the acid reagent and catalyst and the polarity of the solvent. Benzoic acid is found to exhibit a higher reactivity than acetic acid. The catalytic activity of tetraalkylammonium halides increases with increasing ion radius and nucleophilicity of the salt anion. Reduction of the polarity of the solvent (epichlorohydrin and binary mixture of epichlorohydrin:tetrahydrofuran) contributes to the increase of the reaction rate and its regioselectivity (the formation of the "normal" product n-P). The regioselectivity of the reaction is almost independent of the nature of the acid and increases with an increase in the steric factor. A preferential formation of the chlorohydrin ester n-P corresponds to the essential contribution of the SN2 mechanism to the nucleophilic opening of oxirane ring. A symbatic increase in the reactivity of carboxylic acids and the steric factor in the reaction system "carboxylic acid–2-(chloromethyl)oxirane–tetraalkylammonium halide" allows to identifying the mechanism of the catalytic reaction, which corresponds to the mechanism of anion transfer of a nucleophilic reagent by an ion pair.

3-9

Authors: I.R. Buchkevych, M.S. Kurka, V.G. Chervetsova, A.S. Krvavych, N.Ya. Monka, V.I. Lubenets, V.P. Novikov

The paper reports the synthesis of imidazole systems based on derivatives of 6,7-substituted 1,4-naphthoquinone, both those condensed with the naphthoquinonic cycle and the derivatives in which the heterocyclic component was introduced into the quinoid molecule as a separate fragment. The work was done in order to extend the spectrum of the biology action of the synthesized compounds due to the combination of imidazole and naphthoquinoid fragment in a single molecule. A series of 6[(5-amino-2,3-dihydro-1H-1,2,4-triazol-3-yl)-amino]-3-chloro-2-substituted-4-yl-7-nitronaptoquinones, 2,7-dichloro-6-(2,5-dimethyl-1H-pyrrol-1-yl)-3-R-4-yl-nitronaptoquinones and thioxoquinoxalinic derivatives of substituted 1,4-naphthoquinone was synthesized. The conducted studies of antimicrobial and fungicidal activities showed that the introduction of an additional aminotriazole substituent at the position 6 into the molecule of 1,4-naphthoquinone reduces the effect on both gram-positive and gram-negative bacteria. The presence of a pyrrole cycle at the position 7 of 1,4-naphthoquinone increases the activity against gram-positive and gram-negative bacteria. The presence of a thioxoamide cycle at the position 7 of 1,4-naphthoquinone significantly increases the activity against gram-positive and gram-negative microorganisms. Thus, the obtained results may be used for further development of effective antibacterial and antifungal chemotherapeutic remedies.

18-24

Authors: D. Girenko, O. Shmychkova, A. Velichenko

It was shown that the pre-reduced surface of the platinized titanium electrode undergoes a series of transformations during the anodic polarization. Oxygen-containing particles OHads are chemisorbed on the Ti/Pt surface in the low polarizations range. Such particles, depending on the pH of the near-electrode layer, can be in equilibrium with OH2+ads and O–ads. With increasing polarization, the formation of both atomic oxygen and phase oxide layers becomes possible. The formation of phase surface oxides occurs rapidly in supporting electrolytes, and the oxygen evolution proceeds on a completely oxidized surface. The presence of chloride ions in solution significantly decelerates this process. The higher the Cl– concentration, the longer the surface remains in the reduced state. The chloride ion acts as a depolarizer, discharging on the surface and interacting with surface oxygen-containing particles, thereby slowing down the oxidation of the surface. It was established that both direct oxidation of Cl– and its oxidation by labile oxygen-containing particles of the OHads type occur on the reduced platinized surface. On the oxidized surface, the formation of hypochlorite occurs directly on the surface of the layer of platinum phase oxides with the participation of inert chemisorbed oxygen-containing particles and atomic oxygen. The desorption of the products of primary oxidation of Cl– becomes slower, and an increase in the degree of surface filling with active oxygen-containing particles of the Oads type leads to a significant increase in the rate of chlorate formation.

33-38

Authors: Y.I. Koltsova, S.V. Nikitin

This paper reports the results of the study devoted to the preparation of porous glass-ceramic materials by using fuel slag at the temperatures no more than 950C. Glass slag compositions containing 20 to 70 wt.% of glass cullet and 30 to 80 wt.% of fuel slag were investigated. In order to reduce the sintering temperature, various salts were added to their composition, among which Ca(NO3)24H2O and Na2CO3 had the strongest influence on sintering. The introduction of 9 to 15 mass parts of Na2О (introduced as Na2CO3) into the composition and the use of manganese carbonate as a gas-forming agent allowed obtaining porous glass-ceramic materials having bloating coefficient KV=0.77–1.35 and KV=0.77–2.33 at the firing temperatures of 900C and 850C, respectively. If loam was used as a gas-forming agent, the bloating coefficient was equal to 0.55–0.83 and 0.93–1.64 at the firing temperatures of 900C and 850C, respectively. The obtained materials had an uneven macroporous structure due to intense gas evolution. The preliminary heat treatment of the glass slag compositions at the temperature of 950C with subsequent grinding the cake and introducing gas-forming agents resulted in the formation of porous glass-ceramic materials with a sufficiently high bloating coefficient (~4.68 at the firing temperature of 700C) and homogeneous micro- or mesoporous structures (the coefficient of inhomogeneity of the structure being 0.17 and 0.18, respectively).

47-52

Authors: T. Rymar, O. Suvorin

The article reports two methods of preparation of block thermal insulation materials based on liquid glass; a comparative assessment of them is performed. These methods are implemented via volume and contact grouting of the liquid glass granules by the microwave-assisted swelling of a binder. In order to determine the effectiveness of a certain grouting method, the samples were swollen at different power capacities of a microwave oven and the basic operational characteristics of blocks were determined. The obtained results showed that the materials fabricated by volume grouting are characterized by higher strength and lower moisture sorption and water absorption properties than that prepared by contact grouting due to a closer packing of granules and more uniform distribution of the binder in the intergranular space. This is achieved through the use of microwave irradiation in the production of block materials, which ensures uniform heating of all layers of the material and simultaneously allows swelling both the granules and the binder. Therefore, a strongly grouted material is obtained, which can be used as a structural thermal insulation.

61-70

Authors: V. Stavytskyi, О. Voskoboinik, М. Kazunin, I. Nosulenko, S. Shishkina, S. Kovalenko

The heterocyclization of 3-(2-aminophenyl)-6-(4-isopropylphenyl)-1,2,4-triazin-5(2H)-one with 4-oxoheptanedioic acid was studied in this work. It was shown that this reaction yielded partial hydrogenated [1,2,4]triazino[2,3-c]quinazoline, pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline-5a(6H)-yl)propanoic acid or their mixture depending on the reaction condition (the nature of a solvent, the temperature, and the process duration). It was found that the refluxing of initial compounds in acetic acid was the most suitable in the case of the synthesis of 3-(3-(4-isopropylphenyl)-2,8-dioxo-7,8-dihydro-2H-pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazolin-5a(6H)-yl)propanoic acid. The found optimal conditions were used for the condensation of 2-azaheterylanilines with 4-oxoheptanedioic acid. These conditions created the basis for preparative methods for the synthesis of tetracyclic derivatives series. The structure and purity of the obtained compounds were determined by a complex of appropriate physicochemical methods, including 1Н and 13С NMR, IR, chromatography-mass, mass-spectroscopies and X-ray diffraction analysis. The features of the fragmentation of different heterocycles molecular ions under electronic ionization were discussed. It was established that the destruction of pyrrolidone cycle caused higher fragmentation of aromatic pyrrolo[1,2-a][1,2,4]triazоlo[1,5-c]quinazoline system. It was found that the introduction of carboxyethyl fragment into the pyrrolo[1,2-a][1,2,4]triazino-)[2,3-c]quinazoline system was favorable for the formation of anti-inflammatory agents. Pharmacological studies revealed that only substituted pyrrolo[1,2-a][1,2,4]triazino[2,3-c]quinazoline-5a(6H)-propanoic acids showed high anti-inflammatory activity. The series of the obtained compounds demonstrated an anti-inflammatory activity that was comparable to or higher than the pharmacological effect of the reference compound "diclofenac". The essential role of the presence of fluorine atom in the anti-inflammatory activity of the synthesized compounds was discussed.

80-85

Authors: N.Yu. Strutynska, D.О. Danilchuk, M.S. Slobodyanik

The paper reports the peculiarities of the formation of calcium phosphates via precipitation from aqueous solutions in the systems Сa2+–M–PO43––NO3– (where M=Cs+, Zn2+ or Cr3+) at the molar ratios Са2+/РО43–=1.5 and 1.67 and Сa2+/M=2.0; 3.0 or 15.0 and the temperature of 25C. The precipitated samples were heated to the temperatures of 700 and 900C to provide intercalation of impurity cations (M) into the structure of calcium phosphates. The effects of the cation nature (М) and the molar ratio Сa2+/М on the formation of apatite- and whitlockite-related calcium phosphates were established. The mixture of apatite and whitloskite-type phases was obtained for Cs- and Zn-containing systems at the molar ratio Сa2+/М=2.0 and 3.0 in the initial solution, whereas the formation of only apatite-related phase was observed with a significant increase in the value Сa2+/М (up to 15.0). The presence of chromium cation in the initial solution caused the stabilization of a phase based on -Са3(РО4)2 (whitlockite type), while an apatite-related phase is formed in the case of a mixture of Cs+, Zn2+ and Cr3+ cations. The fabricated samples were characterized using powder X-ray diffraction and FTIR-spectroscopy methods. The optimized conditions for the binding of cesium, zinc and chromium cations to form stable apatite- and whitlockite-related calcium phosphates can be further used to develop methods for the immobilization of radioactive isotopes.

92-96

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

The study of the formylation of a geminal system N1–C2–O3 of spiro-3,1-benzoxazines revealed that they are rearranged into hydroacridones with a quantitative yield for 30 minutes when interacting with an equivalent amount of Vilsmeier-Haack reagent at room temperature. If one uses a three-fold excess of Vilsmeier-Haack reagent, chlorine derivatives of hydroacridine are also produced at room temperature with a quantitative yield for 1 hour. It should be noted that hydroacridones have been earlier isolated only as by-products with a low yield. The absence of the C–2 carbon atom signal in the 13C NMR spectra of the products, unlike the starting compounds, where the C–2 signal corresponds to a chemical shift of 89.1–89.2 ppm, testifies to the rearrangement of the carbon skeleton. The chemistry of acridines seems to be interesting and promising due to the biological activity of these compounds. For example, the derivatives of hydroacridine chlorine are key intermediates in the synthesis of monomeric and dimeric derivatives of Tacrine, which are used as acetylcholinesterase inhibitors in the treatment of Alzheimer's disease.

104-110

Authors: T.V. Chernozhuk

The constants of the association (КА), the non-Coulomb interaction parameters (d+–) and the parameters of the Gurney cosphere overlap (А+–) in solutions of 1-1 electrolytes in -butyrolactone (-BL), propylene carbonate (PC) and their mixtures with 1,2-dimethoxyethane (PC+1,2-DME) (1:1) were calculated using experimental data. The effects of temperature, concentration, properties and sizes of particles on interparticle interactions in the investigated solutions of 1-1 electrolytes in -BL, PC and PC+1,2-DME (1:1) were determined. It was established that the square-law potential d+– strongly depends on the solvent nature, temperature and ion size, while the parameter А+– shows a much weaker dependence. This can be used to predict the values of А+– and the ion association constants for a wide range of electrolytes in a given solvent when only limited experimental data are available.

6-16

Authors: O.A. Brazhko, A.S. Yevlash, M.P. Zavgorodnii, M.M. Kornet, O.O. Brazhko, A.V. Lagron

At the present stage of the development of organic and bioorganic chemistry, several basic approaches to the synthesis of pyrrolo[1,2-a]quinolines are known. These compounds are of interest to the researches primarily as bioregulators with a wide spectrum of biological activity. This review is an attempt to systematize and generalize literary data relating to the chemistry of pyrrolo[1,2-a]quinoline and its derivatives as important synthetic substrates and precursors for the design of biologically active substances. The main approaches to the synthesis of these compounds, consisting in various preparative methods for constructing a tricyclic base of pyrrolo[1,2-a]quinolone, were considered. The search for biologically active substances of this series is important and has a practical and theoretical significance.

24-30

Authors: V.A. Vekshyn, E.R. Grabovetskaya, L.P. Abramova

The method of the designing of industrial reactors with metal cellular catalysts is considered in the article. The proposed catalysts can be used for the low-temperature purification of exhaust gases from nitrogen oxides using ammonia. The advantages of catalytic blocks are shown in comparison with the catalysts AVС-10 that is widely used in industry. The procedures of physicochemical study and analytical control are developed. Based on laboratory tests, the sizes and structure of the proposed reactors are determined. Required amount of catalyst in the form of metal cellular blocks is determined for two types of reactors: with rectangular and circular cross-sections. The length of catalytic units is calculated and production technology is proposed. Hydrodynamic calculations demonstrate that block catalysts have lower flow resistance that the granulated ones. The reactors of circular cross-section need catalytic units of smaller volume than rectangular ones; however, the latter have a lower resistance to gas flow. The study shows that the metal cellular catalytic blocks would allow avoiding the use of additional compressors for excessive pressure to purge gases through the catalyst bed, which should reduce economic costs, and, ultimately, reduce the cost of the product.

39-46

Authors: D. Girenko, O. Shmychkova, A. Velichenko

The main features of the processes occurring during the oxidation of chloride ions on the platinum surface were investigated as well as the catalytic activity and selectivity of platinum in the anodic synthesis of hypochlorite were determined. It was assumed that the oxidation of chloride ions on the platinum surface occurs with the participation of particles like OHads or Oads, which are active centers on the surface, according to the mechanisms of chlorine evolution described in literature. In addition, it was taken into consideration that polarization at high anodic potentials decreases the degree of surface filling with labile and simultaneously increases the degree of surface filling with inert particles. The obtained results showed that the formation of chlorine and hypochlorite proceeds with the participation of labile oxygen-containing particles. It was shown that the main three parallel processes are observed during the electrolysis of NaCl as follows: (i) the oxidation of Cl– to hypochlorite, (ii) the formation of chlorate, and (iii) the oxygen evolution reaction. On a pre-reduced surface, the current efficiency of hypochlorite reaches 90% and the process proceeds at polarizations lower by 400–450 mV in comparison to process occurred on an oxidized surface. Under these conditions, chlorates are practically not formed. However, the reduced surface is gradually oxidized in the course of electrolysis process. Therefore, the ratio of active sites at which Cl– oxidation occurs is declined. It was established that weakly bounded (labile) particles take part in the formation of hypochlorite. On the passive surface, the oxidation of Cl– even in 1–2 M NaCl solutions occurs at the limiting current, the value of which is determined by the fraction of active surface centers. Comparison of the values of the limiting currents on the active and passive surfaces allows us to conclude that the ratio of the active centers of the latter does not exceed 5–10%. It was established that the surface of platinum is easily activated during short-term cathodic polarization in the region of hydrogen evolution.

53-59

Authors: L.M. Grishchenko, N.S. Novychenko, I.P. Matushko, O.V. Mischanchuk, V.E. Diyuk

Active low-temperature heterogeneous catalysts of acid-base processes based on fruit-stone activated carbon were prepared in this work. Thermodesorption properties of the samples were studied. Depending on the modification method, one can obtain catalytic materials containing 1.20–1.45 mmol g–1 of surface acidic groups. The prepared samples showed a rather high thermal stability: the decomposition of phosphorus-tungsten acid on the surface of activated carbon occurred at the temperatures of above 600С. It was shown that the modification of the surface of activated carbon by phosphorus-tungsten acid led to the oxidation of the latter, especially at high temperatures; this was confirmed by an increase in the intensity and forms of carbon monoxide evolution in the thermodesorption spectra. The catalytic properties of the synthesized samples were investigated in the reaction of dehydration of isopropyl, ethyl and methyl alcohols in a gas phase. The catalytic activity of modified activated carbon depended on the concentration of acidic centers and the preliminary treatment of the surface of carbon. The temperatures of the maximum conversion of alcohols to the reaction products on the prepared catalysts were stated to be 140–155C, 160–180C and 180–255C for isopropanol, ethanol and methanol, respectively. Preliminary oxidation by nitric acid resulted in an increase in the catalytic activity towards the dehydration of all three alcohols, the temperatures of the course of dehydration reactions diminished by 10–20C. Preliminary oxidation by hydrogen peroxide led to a decrease in the activity of the prepared samples, the temperatures of the reaction of dehydration increased by 5–55C.

69-73

Authors: Ts.I. Dimitrov, Ts.H. Ibreva, А.V. Zaichuk, I.G. Маrkovska, А.А. Amelina, E.V. Каrasik

The synthesis of ferrum-willemite ceramic pigments in the system xFeO(2–x)ZnOSiO2 (where x=0.125–1.00) was investigated in this work. The results of colorimetric measurements (in the system CIEL*a*b*) showed that the concentration of iron(II) oxide in the composition of 0.25 mol is sufficient for preparation of ceramic pigments of red-brown color. An increase in the content of iron(II) oxide in the composition of ceramic pigments from 0.125 to 0.25 mol causes the growth of values of color coordinates а* (up to +26.68) and b* (up to +36.73) as well as lightness L* (up to 48.51). A further increase in the concentration of FeO in pigments to 1.0 mol results in a decrease in the amount of red color: the value of red color coordinate а* falls to +21,87. An effective role of hydrate of silicon(IV) oxide introduced as a quartz-containing component of experimental pigments is also shown. It allows reducing the temperature of their synthesis to 900–1000С. Moreover, the growth of the firing temperature from 900 to 1000С leads to a slight increase in the amount of red color of the developed red-brown pigments (value of color coordinate а* increases from +25.38 to +26.68). By means of the methods of X-ray phase analysis and electron paramagnetic resonance, it was found that willemite solid solution and spinel (zinc ferrite) act as a carrier of color in these ceramic pigments. Formation of the above crystal phases is completed already at the firing temperature of 1000С. The synthesized pigments can be successfully used for coloring of glaze coatings on ceramics as well as glass-enamel coatings for metals.

83-91

Authors: T.A. Karavayev, V.A. Osyka, V.O. Komakha, N.V. Kaluga, V.V. Tkachuk, O.O. Sikorskyi

The article presents the results of the IR-spectroscopic study of the processes of chemical interaction in the system mineral filler–modifier–binder, which can occur in the production of water-dispersion paints and affect the operational properties of the obtained coatings. The investigated model systems included mineral fillers (chalk as a carbonate filler for norplasts (designated as CFN) or kaolin from Prosianivske deposit (designated as KC)), modifiers (sodium salt of polyacrylic acid as a dispersant (designated as Axilat 32S) and potassium methyl silicone as a water repellent (designated as GKZh-11k)), and binders (aqueous dispersion of styrene-acrylic copolymer (designated as Ucar DL 450) or organosilicon polymer (designated as IE-2404)). The analysis of the obtained IR-spectra showed the possibility of the interactions in the following systems: Ucar DL 450+Axilat 32S involving C=C bonds and functional groups of OH, Ucar DL 450+GKZh-11k with the participation of OH, Si–H and C=C groups, and Axilat 32S+GKZh-11k via OH groups. A partial chemical interaction with the participation of C=O groups of the filler is possible in the system CFN+Axilat 32S. The replacement of Axilat 32S by potassium methyl silicone is associated with the chemical interaction with the chalk surface by means of adsorbed water and the C=O groups. After washing with water, this feature remains which allows predicting the formation of a surface layer of potassium methyl silicon molecules on the particles of CFN that provides its hydrophobization. The presence of interaction processes is also detected in the system KC-1+Ucar DL 450. This is evidenced by a decrease in the intensity of the first group of absorption bands by 20–25% and the appearance of the absorption band of the C–H bond. The system KC-1+IE-2404 is characterized by the interaction processes with the participation of the OH groups on the kaolin surface; the generated bonds show a hydrolytic stability.

99-106

Authors: T.P. Kovalenko, V.O. Serdiuk, V.B. Vostres, H.F. Matiko

This paper reports a kinetic investigation into the emulsion (co)polymerization of decyl meth- and decyl acrylate with methyl acrylate for the first time. The obtained results are used to prepare copolymers based on the products of the emulsion (co)polymerization. It is determined that decyl methacrylate does not homopolymerize with the formation of emulsions regardless of the nature of an emulsifier, its solubility and initiator structure. Moreover, they reduce the rate of copolymerization with methyl acrylate. The deceleration of the copolymerization in the presence of long-chain monomers is related to the a low activity of decyl (meth)acrylate as compared with methyl acrylate. The colloid-chemical and physicochemical properties of the synthesized dispersions are investigated. The position of the maximum of the dependences of viscosity and surface tension on the polymer composition coincides with the smallest particle sizes of the dispersion; hence, the alterations in the viscosity and surface tension of the dispersion are associated with the variations in particle sizes, which results in the changes in the interface surface area. The molecular weight distribution of emulsion copolymers is studied by a turbidimetric titration technique. The absorption of water, the strength and specific elongation of the (co)polymer films are determined by tension testing. Diffusion coefficients are calculated according to the first section of the water absorption curve; the obtained values show the deceleration of the rate of the water absorption by the copolymer film as compared with the polymethyl-acrylate films. The tensile strength of the poly(methyl acrylate-co-decyl acrylate) films is less than that of the poly(methyl acrylate-co-decyl methacrylate) ones, which corresponds with the well-known facts concerning the influence of a methyl substituent in an -position on the polymer properties. The addition of hydrophobic co-monomers, decyl meth- and decyl acrylate, to the structure of macromolecules with methyl acrylate strongly affects the properties of the dispersion and derived films, which is connected with the significant structural transformations of macromolecules in the dispersions and films.

113-120

Authors: O.A. Kostyk, O.H. Budishevska, V.B. Vostres, Z.Y. Nadashkevych, S.A. Voronov

This article presents a simplified method for the preparation of cationic starches with a different degree of substitution using triethylamine and epichlorohydrin as starting materials. The optimal conditions for a starch cationation by a semi-dry method have been determined. The cationic starch with quaternary ammonium cation groups was prepared by the interaction of an aminating reagent with corn starch in the presence of sodium hydroxide. The aminating reagent, 3-chloro-2-hydroxypropyltriethylammonium chloride, was synthesized by the one-pot interaction between triethylamine and HCl followed by the reaction with epichlorohydrin in the presence of cetyltrimethylammonium bromide as a catalyst. The cationic starches were fabricated with the degree of substitution of hydrogen atoms in starch hydroxy groups equal to 0.02–0.45. The effects of molar ratios of sodium hydroxide to the aminating reagent and the aminating reagent to starch (with respect to a D-glucopyranose unit) in the initial reaction mixture on the degree of substitution were investigated. It was shown that the cationic starch with the highest degree of substitution was formed at an optimal starting molar ratio of sodium hydroxide to the aminating reagent that is equal to 1.2–2.0. An increase in the molar ratio of aminating reagent to starch significantly increases the degree of substitution when the content of sodium hydroxide is less than the optimal value. The reaction efficiency of the cationation of corn starch decreases with an increase in the molar ratio of aminating reagent to starch (in the test range of 1.0 to 6.0).

128-135

Authors: V.M. Moskalyk, O.G. Arkhypov, V.G. Sozontov, I.L. Kovalenko

The aim of this work was to study the influence of temperature and initial concentrations of the components of the system on both the equilibrium composition of the liquid phase in the mixture "nitrogen oxides–nitric acid–water" and the content of a final product in the production of liquid mixtures N2O3–N2O4. The obtained results allow determining the main parameters of the distillation of stratifying mixtures "nitrogen oxides–nitric acid–water" in the production of N2O3–N2O4 solutions and justifying the choice of the composition of the mixture that is used for distillation. Based on experimental data, we showed that the optimal mass ratio N2O4:H2O in the prioduction of liquid mixtures N2O3–N2O4 is equal to (3–8):1, which corresponds to equilibrium concentrations of HNO3 in a liquid phase of 65–70 wt.%. The influence of temperature on the content of HNO3 and H2O in the vapor phase above the solutions of the HNO3–H2O–nitrogen oxides was investigated. The temperature dependence of the NO content in the vapor phase was established at various contents of the initial components. It was suggested that the appearance of maxima in the dependence involved was due to the predominance of the processes of decomposition of nitrous acid and dissociation of N2O3 in the range of lower temperature, whereas a further increase in the temperature resulted in an increase in the vapor pressure of nitrogen oxide(IV) and a decrease in the concentration of NO. A mathematical dependence of the equilibrium concentration of nitric acid on the initial ratio N2O4:H2O, temperature and initial concentration of HNO3 was derived. The obtained equation allows determining the equilibrium mass concentration of nitric acid with a sufficient accuracy for the ranges of the initial mass ratio N2O4:H2 of 1:2 to 12:1, the temperatures of 293–353 K and the initial HNO3 concentrations of 40–68.4 wt.%.

144-148

Authors: P. Daniel Nixon, C. Joseph Kennady

Manganese-nickel oxide films were electrodeposited on a stainless steel plate substrate in a bath containing manganese sulfate, nickel chloride and a non-ionic surfactant. The structural, morphological and electrochemical properties of these films were investigated. The X-ray diffraction pattern revealed the grain size of the material and confirmed the presence of manganese oxide and nickel oxide in the films. The preparative parameters, such as potential window, scan rate, bath concentration and numbers of potential cycles, were optimized during potentiodynamic deposition. The cyclic voltammetry was used to study the reduction and oxidation mechanism during the electrodeposition process. The charge-discharge method was applied to study the capacitor property of the synthesized material.

157-163

Authors: L.K. Patrylak, O.P. Pertko, V.A. Povazshnyi, O.V. Melnychuk

Up-to-date fluid catalytic cracking catalysts for large-tonnage refining processes work under extremely hard conditions and need to have a high stability to the thermal and steam treatment. Therefore, the purpose of this work was to compare the effect of lanthanum and zirconium additives on the porous characteristics and catalytic activity of the microspherical cracking catalysts in fresh and steamed form that were synthesized based on the Ukrainian kaolin. The synthesized initial sample contained 30% Y zeolite that was transferred to the H-form before the modification by lanthanum and zirconium. The modification led to some decrease in BET surface and samples microporosity, which was substantially intensified after steaming. In the case of zirconium, such a decrease was less than for lanthanum. The effect of the catalysts modification on the vibrations of the structural components of the zeolite lattice was investigated by FTIR spectroscopy. The observed shifts of absorbance frequencies of the bond at 1070 cm–1, which correspond to the asymmetric vibrations of tetrahedra after corresponding modifications, indicated the isomorphic substitution of the aluminum atoms by zirconium ones. The steamed samples with the zirconium content of 6.5% demonstrated the highest conversion of cumene cracking (an increase by 20–30% as compared with the unmodified sample). Therefore, the modification of fluid catalytic cracking catalysts by zirconium affects both on the adsorption and on the catalytic properties of the steamed samples.

170-176

Authors: I.G. Radzievska, O.P. Melnyk, V.M. Pasichnyy, A.I. Marynin

When developing heterogeneous food systems that contain a liquid–liquid interface, surface-active substances (surfactants) are used to reduce the surface tension and promote the stability of the emulsions. Phosphatidylcholine is a common food additive, which is widely used in emulsion products. At the same time, the physical-chemical properties of phosphatidylcholine have not been fully investigated, and its surface-active properties are not known to date. This work reports the properties of the surface layer of phosphatidylcholine obtained by step extraction from the phosphatidic complex of chicken eggs, sunflower oil and soybean oil. Based on the calculated values of the limiting adsorption, the thickness of the adsorption layer and the surface area occupied by one molecule, the identity of the surface-active properties of the studied surfactants was shown when a water-in-oil type emulsion is formed, irrespective of the source of raw materials (animal and vegetable origins). NMR 31P spectroscopy method revealed that there was no significant difference in the group and fatty acid compositions of the studied samples (0.5%). The value of the hydrophilic-lipophilic balance of the phosphatidylcholine was stated to be 6.475; thus, it belongs to the amphoteric emulsifiers of water-in-oil type emulsions. The concentration of structural transformations was determined to be 0.3%; therefore, one can prepare stable oil-water emulsions without the use of additional co-emulsifiers. The obtained data may be used for the precise selection of the composition of multi-component stabilization compositions and effective control over the stability of the structured systems.

184-189

Authors: Y.D. Rublova, N.V. Amirulloeva, V.S. Protsenko, F.I. Danilov

Surface activity of sodium dodecylsulfate and micelle formation in solutions based on deep eutectic solvents ethaline and reline (eutectic mixtures of choline chloride with ethylene glycol and urea, respectively) were investigated. The isotherms of surface tension were treated using Langmuir model and the adsorption parameters at the interface "solution/air" were determined. The change in the nature of a solvent results in a decrease in the adsorption equilibrium constant in the following sequence: water>reline>ethaline>ethylene glycol, which is caused by the corresponding changes in the solvents polarity and intensity of hydrophobic interactions. The critical micelle concentration of sodium dodecylsulfate is equal to 3.5510–3 М and 2.1410–3 М in solutions based on ethaline and reline, respectively. These values are lower than that in an aqueous medium (8.1110–3 М). An increase in the content of water additive in deep eutectic solvents has only a marginal impact on the adsorption equilibrium constant, but leads to an increase in the critical micelle concentration.

197-204

Authors: O. Stashkiv, V. Vasylechko, G. Gryshchouk

The sorptive properties of the acid-modified Transcarpathian clinoptilolite towards Gd(III) under dynamic conditions were investigated. The sorption capacity of the clinoptilolite in H-form depends on the nature and concentration of acid-modifier. The most effective sorption of Gd(III) was observed when clinoptilolite was pretreated with 1 M H2SO4 solution. The sorption capacity of the H-form of Transcarpathian clinoptilolite towards Gd(III) significantly depends on the concentration of gadolinium salt, the pH of solution and the temperature of the preliminary calcination of the sorbent. The sorption capacity of H-clinoptilolite under optimal conditions (diameter of zeolite grains was 0.20–0.31 mm; flow rate of gadolinium(III) solution with concentration 0.5 µg/mL through sorbent was 5 mL/min; and pH 10.0) was 8.2 mg gadolinium per 1 g of acid-modified clinoptilolite. The H-clinoptilolite sorbs the Gd(III) trace amounts even in the presence of other common ions. The solutions of 1 M HCl and 1 M KCl acidified by a hydrochloric acid to pH 4.0 are the most effective desorbents of gadolinium(III) ions from H-clinoptilolite. The method for gadolinium trace amounts preconcentration from aqueous solutions in a solid phase extraction mode with a further determination of this rare earth element by a spectrophotometric method was developed. The detection limit of this method is 0.3 ng/mL, and the linearity was evaluated in the range of 1–200 ng/mL.

213-220

Authors: V.I. Sytar, I.M. Kuzyayev, K.M. Sukhyy, O.S. Kabat, E.A. Belyanovskaya

Experimental and theoretical studies in the field of development and modernization of gas-filled polymeric materials were analyzed. The foamed material structure was shown to be dependent on the nature and concentration of porogens. The choice of phenylone as a polymer matrix and magnesium carbonate as a gasifier was substantiated to develop heatproof foamed polymer compositions with increased strength properties. Thermal gravimetric analysis of the substances formed at the temperatures of phenylone transitions to the state of viscous flow with emission of gaseous products was performed. According to experimental results, magnesium carbonate (MgCO3) was chosen as a porogen that is decomposed during heating with the formation of carbon dioxide and magnesium oxide. The most intense gas production process proceeded at 590 K during 15–20 min. The high values of melt viscosity of aromatic polyamide phenylone considerably blocked pore formation in the bulk of a polymer. In order to decrease the viscosity of the melt composition, it was doped with 2–3 wt.% of oligodimethylsiloxane. The results of thermomechanical study revealed that magnesium oxide, which was formed when magnesium carbonate was decomposed, have a thermostabilizing effect on the polymer, which resulted in an increase in the glass transition temperature of phenylone. It was shown that the main characteristics of the developed materials (density, thermal conductivity, and specific heat capacity) were strongly affected by porogen concentration. The study of the surface morphology of the samples exhibited a highly dispersed structure in the polymer volume with pore size close to 100–300 m. Comparative analysis of foamed phenylone and commercial foamed plastics revealed that the maximal operational temperature was about 653 K for the materials developed in this work, whereas this parameter was close to 423 K for known foamed plastics. The developed material can be recommended to use for heat insulation in aircraft and aerospace industries.

228-235

Authors: Y.A. Titov, N.M. Belyavina, M.S. Slobodyanik, V.V. Chumak, O.I. Nakonechna

The conditions of isovalent substitution of lanthanum atoms for dysprosium atoms in A-positions of the SrLa2Sc2O7 two-slab perovskite-like structure of the SrLa2Sc2–xInxO7 type have been determined as follows: 0x1.60. Samples with x1.7 are multiphase and contain a number of additional phases, the main one being the phase with a cubic structure (а1.06 nm). Orthorhombic crystal structure (Fmmm space group) of the SrLa2–xDyxSc2O7 phases with the substitution degree of lanthanum atoms of 0.5, 1.0 and 1.5 was determined by the Rietveld method. The SrLa2–xDyxSc2O7 crystalline structure is based on two-dimensional (infinite in the XY plane) perovskite-like blocks, consisting of two slabs connected by vertices deformed ScO6 octahedra. Neighboring blocks are separated by a slab of A2O9 polyhedra (A2=Sr+Ln (x=0; 0.5 and 1.0) or Ln (x=1.5) in such a way that there are no direct Sc–O–Sc bonds between the octahedra of neighboring blocks. The blocks are connected through the O–A2–O bonds. Eight oxygen atoms of the A2O9 polyhedron belong to the same block as the A2 atoms, and the ninth oxygen atom belongs to the neighboring block. A1 atoms (A1=Sr+La (x=0, 0.5 and 1) or only Sr (x=1.5)) are located at 4b position in the intrablock voids of the SrLa2–xDyxSc2O7 slab perovskite-like structure and their coordination polyhedron is a deformed A1O12 cuboctahedron. It is established that isovalent substitution of lanthanum atoms by smaller dysprosium atoms leads to a gradual change in the distribution of strontium and lanthanides atoms in the interblock (8i) and intrablock (4b) positions of the SrLa2–xDyxSc2O7 structure: from partially ordered (x=0) to fully ordered (x=1.5). In this case, dysprosium atoms replace strontium atoms at the block boundary, and the decrease in the content of lanthanum atoms in the 4b intrablock position is compensated by the strontium atoms invasion. Analysis of the structural features of the SrLa2–xDyxSc2O7 phases showed that an increase in the degree of isovalent substitution of lanthanum atoms leads to a significant (more than twofold) increase in the deformation degree of the A2O9 interblock polyhedra and a decrease in the A2–O interblock length. Such structural changes, which result in a destabilization of the interblock "stitching", become one of the main destruction factors of the layered perovskite-like structure of the SrLa2–xDyxSc2O7 phases at x>1.6 and cause the absence of the SrDy2Sc2O7 scandate. The obtained data on the composition/structural features relations of the slab perovskite-like structure could be used for the purposeful regulation of the structure-sensitive properties of the SrLa2–xDyxSc2O7 type phases.

241-246

Authors: I.V. Fesych, S.A. Nedilko, N.I. Sabadash, O.G. Dziazko, T.A. Voitenko, O.V. Grabovska, M.A. Zelenko

Polymer composite with difference amount of polyvinyl alcohol (PVA) were synthesized using co-precipitation method. X-ray analysis showed the phase identity of the synthesized composite materials. The samples were indexed in hexagonal syngony (space group P63mc). It was found that the average crystallite size of ZnO is about 39 nm, while it is about 23 nm for ZnO/10%PVA. It was noted that the addition of polymer modifier agent played a vital role in controlling the growth of the crystal during the synthesis of ZnO-polymer composites. Unmodified ZnO had higher photocatalytic activity than the modified one. Thus, almost 100% decolorization of a Rhodamine B water solution was observed after 150 min, while only every tenth molecule of the dye was destroyed in the presence of the ZnO/30%PVA. The rate of photocatalytic degradation of organic molecules was significantly smaller in the presence of the oxide-polymer composite because adsorption layer of the PVA molecules on the surface of ZnO particles was formed. This significantly reduced the sorption of Rhodamine B from solution and increased its photostability. It was shown that the degradation efficiency decreased with increasing of the polymer modifier content in the samples. The obtained results have important technological importance since the synthesized composites can be used as UV filters and ingredients of sunscreens.

255-262

Authors: R.E. Khoma, V.N. Baumer, P.B. Antonenko, A.O. Snihach, V.V. Godovan, A.A. Ennan, R.M. Dlubovskii, V.V. Gelmboldt

Aminomethanesulfonic acid (Ia), and its N-methyl (IIa), N-n-propyl (IIIa), N-tert-butyl (IVa) derivatives were synthesized (IIIa has not been previously described) and characterized by means of X-ray diffraction analysis, IR spectroscopy, and mass spectrometry. Aminosulfonic acid 3a of zwitterionic structure crystallizes in the orthorhombic space group Iba2 with the following cell parameters: a=8.8405(6) Å, b=20.6348(12) Å, c=8.0433(7) Å, ===90, V=1467.27(18) Å3. The aqueous solutions of sodium salts (Ib–IVb) were prepared by reacting NaOH with the corresponding Ia–IVa acids in equimolar amounts. The toxicity of Ib–IVb was studied on 132 mice. The derivatives of aminomethanesulfonic acid belong to almost non-toxic compounds (V category of toxicity) following both intraperitoneal and oral administration in mice. According to the LD50 values, the compounds could be ranked in the following order: IIIb (2110 mg/kg)

268-274

Authors: G.N. Shabanova, A.N. Korohodska, S.V. Levadna, O.A. Gamova

Three-component systems CaO–CoO–MoO3, CoO–Al2O3–MoO3 and CaO–Al2O3–MoO3 are characterized in this work. The results of the research of the subsolidus structure of the systems under study are given. Diagrams of the systems in the field of the subsolidus are presented. The calculations of the changes of Gibbs free energy are performed at different temperatures for the model reactions. The thermodynamic and geometric topological calculations based on the developed thermodynamic database allow establishing the direction of solid-phase reactions in the three-component systems CaO–CoO–MoO3, CoO–Al2O3–MoO3 and CaO–Al2O3–MoO3 with the participation of steadily existing compounds; as a result, all conodes in these systems have been determined. The main geometric topological calculations of elementary triangles and phases of systems are performed. Geometric topological system performance is important for the prediction of the accuracy of a dosage of components and the duration of their mixing before synthesis to obtain materials with the specified phase composition. The data on subsolidus structure of the considered three-component systems are essential for further forecasting phase structure of the aluminate cements fabricated with the use of the waste of cobalt catalysts that additionally contain molybdenum oxide.

5-13

Authors: R.D. Apostolova, A.S. Baskevich

Potassium vanadate was synthesized by chemical and electrochemical deposition from a solution of potassium metavanadate to use in cathodes of lithium batteries. After annealing (350C), the deposits contained KV6O15 vanadate mixed with hydrated vanadium oxides. The prepared materials were tested in the electrodes with an electrically conducting additive. The reversible capacity of the synthesized material obtained by chemical deposition in an electrode (11.068.00.25 mm) in the electrolyte containing 1 mol L–1 LiClO4, propylene carbonate and dimethoxyethane was 140–150 mA h g–1 in the voltage range of 3.8–2.4 V. The capacity of the samples with a mass of 30–40 mg cm–2 obtained by deposition on the anode, reached 237 mA h g–1 with respect to the active component in 8–10 cycles. The observed discharge rate (0.1 mA cm–2) of potassium vanadate with particle sizes exceeding the submicron level and with a mass of 30–40 mg cm–2 was comparable to that of a nanometer K2V8O21 vanadate with a mass of 1 mg cm–2 (50 mA g–1). The ability of the synthesized vanadates to genarate more than 200 mA h g–1 in the voltage range of 3.8–2.4 V can provide a higher energy than that of nanomaterials-analogues in the range of 3.8– (1.0–1.5) V.

22-26

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

New Schiff bases were synthesized by the reaction of tetracyclic formyl derivatives of xanthenes with aromatic amines in the presence of a vapor of acetic acid drops. The structures of these compounds were investigated by FTIR, NMR spectroscopies and mass-spectrometric technique. Formyl xanthenes showed absorption and emission in the range of 424–435 nm and 524–559 nm, respectively, in solvents with different polarities. Initial formyl xanthenes were characterized by a sufficiently high Stokes shift of 100–130 nm and a moderate fluorescence quantum yield. The prepared Schiff bases exhibit no fluorescence, with the exception of two products with antranilic acid. These compounds show weakly structured absorption spectra with maxima at 527 nm and 532 nm. Luminescence maxima were found in the range of 582 and 598 nm; as a result, the prepared compounds are characterized by low fluorescence quantum yields in the range of 0.01–0.02 in acetonitrile solution and the Stokes shift of 55 nm and 65 nm.

34-41

Authors: M.M. Zhyhailo, O.I. Demchyna, I.Yu. Yevchuk, B.I. Rachiy, V.V. Kochubey

The synthesis of a series of hybrid polymer-inorganic membranes based on acrylic monomers (acrylic acid, acrylonitrile and 3-sulfopropylacrylate potassium salt) and sol-gel system 3-methacryloxypropyltrimethoxysilane–ethanol–water with various ratios organic/inorganic is reported in this paper. The synthetic procedure includes UV-initiated polymerization of monomers in the presence of photoinitiator and cross-linker and sol-gel process in situ. A high content of gel fraction (>95%) indicates the successful synthesis and formation of cross-linked polymer-inorganic structures insoluble in organic solvents and water. Investigations performed by means of impedance spectroscopy showed high proton conductivity of membranes (10–4–10–2 S cm–1) and its dependence on temperature and material composition. The prepared membranes have relatively good chemical stability in the time interval of testing and high ion-exchange capacity (1.12–1.68 meq g–1). Thermogravimetric study showed the influence of the content of inorganic component on the increase of thermal stability of the membranes. Consequently, taking into account the complex of the characteristics, the synthesized organic-inorganic materials is a potential candidate for DMFC application.

48-53

Authors: Y.I. Koltsova, S.V. Nikitin

The paper is focused on increasing the crystallization degree of porous glass-crystalline materials to improve their mechanical properties. The search for a favorable heat treatment method is one of the ways to achieve this. This study reveals the influence of the temperature-time mode on the samples properties in the course of the roasting process; the procedure includes endurance at the temperature of 600C during cooling. It is determined that the application of the specified roasting mode has a number of advantages in comparison with slow cooling of the samples together with a furnace. The proposed method of roast provides a decrease in the content of a crystalline component and ensures a significant decrease in the coefficient of constructive quality of the studied materials (on average 16.3%). The influence of micro-wollastonite additives in the amount of 1.5–7.5 mass fractions (beyond 100%) on the properties of experimental porous glass-ceramic materials is also investigated. The additive increases the crystallization degree and allows achieving the formation of wollastonite crystals. It is established that the use of the additive under consideration increases the mechanical characteristics of the samples (for instance, coefficient of constructive quality increases from 15.17 to 16.33) due to crystallization of wollastonite in the interporous partitions; this provides a reinforcing effect with respect to the whole material.

58-64

Authors: H. Lavrenyuk, B. Mykhalichko

This paper reports the results of determination of tensile strength, surface hardness, water resistance and chemical resistance of polymer materials based on the self-extinguishing epoxy-amine composites modified with copper(II) carbonate. This allowed forming the basics of a new type of polymer materials with enhanced physicochemical and mechanical properties. The results of the experiments showed that the use of CuCO3, which is considered as a flame-retardant agent of epoxy-amine composites, not only suppresses the spread of the flame, thereby effectively reducing the fire hazard but also improves the performance characteristics of the produced polymer coatings. Due to its exceptional complexing ability, copper(II) carbonate is readily incorporated into the structure of an epoxy polymer, which ensures that the composite materials retain their performance characteristics at an appropriate level. The addition of CuCO3 to epoxy-amine composites in the amount of 20–40 mass parts per 100 mass parts of binder increases the tensile strength and the surface hardness by 67.8–87.2% and 19.7–21.5%, respectively, in comparison with the original composition. It was also found that epoxy-amine composites with CuCO3 additives are characterized by increased water resistance and resistance to aggressive environments.

71-76

Authors: A.M. Makeiev, T.Ie. Keda, L.M. Potiha, O.A. Zaporozhets

New derivatives of [1,2,4]triazoloazines substituted in the amine-rearrangement are synthesized using a novel approach that is based on the cyclization of methyl (E)-4-hydroxy-4H-1,2,4-triazole-4-amine salts with bromo-2-butenoate and methyl 2-(bromomethyl)benzoate. The influence of the solvation shell of dimethyl sulfoxide, acetonitrile, ethanol and their mixture with water on the spectral characteristics of the new compounds in solutions was investigated. The molecules are sensitive to changing the solvate shell in solutions; they are characterized by a positive solvatochromic effect when solvent polarity is increased. Their solutions in dimethyl sulfoxide show intense blue fluorescence (em=460–468 nm), which decays with time. It was shown that water quenches the fluorescence of 1-amino[1,2,4]triazolo[1,5-b]isoquinoline-1-ol-10-olate in organic solvents. The intensity of fluorescence of 1-amino-10-hydroxy-1H,5H,10H-[1,2,4]triazolo[1,5-b]isoquinoline-4-one increases with an increase in the water concentration in dimethyl sulfoxide in the range of 0.05 to 0,5% (v/v). This means that this molecule can serve as a highly sensitive probe for the determination of water level in dimethyl sulfoxide.

84-92

Authors: A.V. Mishchenko, E.V. Mishchenko, E.A. Venger, D.S. Kachuk, T.A. Popovych

The paper reports the results of the study on the hydrolytic stability of films obtained from aqueous dispersions of polyurethane ionomers of sulfonate and carboxylate types, in particular the effect of the process duration of films in aqueous solutions of soda and surface-active substances on the bursting tension during stretching was investigated. This indicator is important when using dispersions as binders in pigment compositions for the printing of textile materials, because the indicators of the stability of colorings to wet treatments, in particular to washing, depend on the properties of dispersions. It was found that the investigated polyurethane ionomers do not provide the stability indicators, which would be expected from a polyurethane nature of the binder. An assumption was made that this results from an insufficient stability of some polyurethanes to hydrolysis. For increasing the polymer stability to hydrolysis and the stability of colorings to wet treatments, we tested the possibility of increasing the density of a three-dimensional structure of polyurethane. To this end, pre-condensates of thermosetting resins, which are widely used in finishing works, were used. An increase in the stability of both films of polyurethane ionomers and the coloring formed was stated when using the binders of the specified type in the presence of pre-condensates of thermosetting resins. The mechanism of the action of the pre-condensates of thermosetting resins was determined in the formation of polyurethane films. It was established that a high efficiency of additives of pre-condensates of thermosetting resins towards the polyurethane binder is ensured by the resin formation and the formation of a composite-type film with increased strength characteristics on the surface of a fabric. The formation of a polymer system of the specified type provides high coloring stability and improves performance characteristics of a textile material.

104-111

Authors: O.V. Perlova, E.I. Tekmenzi, N.А. Perlova, A.P. Polikarpov

Some characteristics of sorption recovery and concentration of uranyl ions from model nitrate solutions by fibrous ion exchangers FIBAN C-1 (a cation exchanger) and FIBAN AC-22V (an amino-carboxyl polyampholyte) under dynamic conditions were established. It was shown that effective recovery and concentration of uranium(VI) is combined with a high rate of uranium sorption. Quantitative characteristics of uranium sorption under dynamic conditions (dynamic exchange capacity, total dynamic exchange capacity, uranium content in the phase of the sorbent and sorption rate) were calculated. It was established that the fibrous cation exchanger FIBAN C-1 manifested better uranium(VI) sorption properties from model nitrate solutions (maximum sorption is equal to 0.23–0.34 mmolg–1) and concentration of these solutions (100–115 times) than polyampholyte FIBAN AC-22V (maximum sorption is equal to 0.011–0.014 mmolg–1, concentration is only 2.5 times). It was shown that a 10-fold increase in the rate of solutions transmission through FIBAN fibrous ion exchangers (from 2.5 to 25 cm3min–1) resulted in an insignificant degradation (~1.2–1.5 times) of the characteristics of sorption process. It was experimentally found that the initial form of the fibrous ion exchangers can be fully restored by passing of 10 and 16 column volumes of a 0.5 M HNO3 solution through the ion exchangers FIBAN C-1 and FIBAN AC-22V (in uranyl form), respectively.

118-125

Authors: A.Yu. Poloz, N.R. Prokopchuk, R.M. Dolinskaya, Yu.R. Ebich

The viscoelastic properties of epoxy resin-based composites ED-20 in a mixture with aliphatic epoxy resin DEG-1 have been determined as functions of the applied industrial polyamine hardener and additional heat treatment (at the temperatures of 60–140С). The differences in the thermomechanical and physical-mechanical properties, and wear resistance of the composites have been stated resulted from the change in the ratio of the energies of elastic and viscous deformation. The ratio of the energies of elastic and viscous deformation of composites in a dynamic loading mode is influenced by the formed spatial cross-linked structure of the epoxy matrix. The effects of the temperature of additional heat treatment on the change in thermomechanical properties and the nature of the destruction of epoxy composites have been shown. It has been proposed to apply a combined heat treatment conditions (80+100C). To achieve optimum viscoelastic properties after hardening at 20C, it is expedient to heat-treat the obtained epoxy composites in a vitreous state at temperatures close to vitrification temperature and use a Polyamine B hardener.

135-142

Authors: L.O. Snizhko, N.L. Gurevina, O.O. Kalinichenko, V.O. Holovenko, K.V. Roienko

Plasma electrolytic oxidation of lightweight metals performed in water-based solutions is usually accompanied by both the release of a large volume of gases (mainly H2 and O2) and heat emission. Today, the existing electrochemical concepts that tend to explain the oxidation mechanisms involved in the metal conversion under the plasma electrolytic oxidation discharge regime do not provide a clear explanation about these phenomena. In this paper, the critical role of the exothermic thermochemical reactions that occur in micro-discharges between the metal particles emitted from the substrate by discharges and the surrounding water vapour (2Al+6H2O=2Al(OH)3+3H2+Q) is considered. This reaction is thermodynamically favourable over a wide temperature range from room temperature to temperatures far in excess of the melting point of aluminium (660C). This means that the main product of the reaction between dispersed aluminium and water is aluminium hydroxide Al(OH)3. At the same time, conditions realised in spark discharges allowed forming also Al2O3, because it is the most stable product at high temperatures. Comparison between the calculated amount of aluminium oxide, performed using the characteristics of individual discharges, and experimental results taken from the literature revealed that the thermochemical reactions is mainly responsible for both the large amount of gas release and heat emission during the plasma electrolytic oxidation of aluminium.

153-159

Authors: A.B. Tarnavskyi, U.V. Khromyak, R.B. Veselivskyy

The data of temperature-modulated differential scanning calorimetry, thermomechanical and microscopic analyses allowed establishing the effects of poly-N-vinylpyrrolidone (PVP) on the suprаmоleculаr structure in the mixtures of PА-6–PVP and PА-66/6–PVP, crystallite sizes, degree of material crystallinity and temperature of physical transitions. The thermodynamic compatibility between the components of polyamide–PVP mixtures in the viscous-fluid state is determined. The compatibility between PА-6 and PVP is manifested as one endo-peak observed in the curves of differential scanning calorimetry. The endо-effect is somewhat blurred for the case of PА-66/6. This is explained by the presence of links with various structures in PА-66/6. An increase in PVP content in the mixtures also leads to the growth of the maximal temperatures of peaks in the processes of melting and crystallization and the expansion of their temperature and time ranges. Thermomechanical study showed that the melting temperature increases with an increase in the content of PVP in the case of PА-6–PVP mixtures, whereas it decreases in the case of PА-66/6–PVP mixtures. A decrease of deformation in the area of highly elastic state is observed. Microscopic study of the structure of the materials based on modified polyamides revealed the growth of the size of suprаmоleculаr formations and significant changes in the interphase layers. However, the size of crystal formations in the mixtures of PА-66/6–PVP is slightly smaller than in PА-6.