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

4-19

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

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

26-32

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

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

38-43

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

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

50-58

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

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

69-74

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

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

83-90

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

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

99-105

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

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

115-123

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

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

134-141

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

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

151-158

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

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

165-170

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

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

3-10

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

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

18-23

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

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

30-35

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

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

46-52

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

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

63-67

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

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

73-80

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

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

88-97

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

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

104-111

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

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

5-15

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

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

31-37

Authors: Assaf H. Tawfeeq, Bushra B. Qassim

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

43-54

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

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

60-65

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

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

72-79

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

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

88-95

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

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

106-114

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

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

121-127

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

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

134-139

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

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

148-156

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

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

163-171

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

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

177-186

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

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

194-200

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

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

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.