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

12-22

Authors: R.I. Havryliv, V.V. Kochubei, I.V. Lutsyuk

On the basis of the analysis of known literature data on CaCO3 thermal decomposition, it is concluded that the development of a compact engineering CFD model (computational fluid dynamics) for limestone calcination is a topical issue. This model can be based on thermogravimetric data and standard mathematical approximation algorithms. Experiments on thermal decomposition of finely dispersed limestone waste particles of different fractions less than 315 m were carried out using a Q-1500 D derivatograph (system F. Paulik, J. Paulik and L. Erdey) under non-isothermal conditions. Based on differential equations of topochemical solid-state kinetics and the asymmetry of differential thermogravimetry (DTG) curves, the values of activation energy, pre-exponential factor in Arrhenius equation were calculated and the reaction mechanism of the thermal decomposition of particles was determined from the results of non-isothermal experiments performed at the heating rate of 10C/min in a temperature range of 600 to 900C. A new engineering approach was developed to the CFD simulation of the thermal decomposition of limestone wastes by means of a two-step mechanism of solid-state kinetics using commercial CFD code ANSYS Fluent. The findings could be used in chemical engineering to produce new highly efficient equipment.

29-33

Authors: V.F. Zinchenko, V.P. Sobol, I.R. Magunov, O.V. Mozgova

We showed that germanium monoxide can be used for the fabrication of thin-film coatings by thermal (resistive) vacuum evaporation and condensation on substrates made of different materials. To stabilize germanium (II) valent state in its monoxide, the introduction of boron oxide additives is proposed and justified. H3BO3 is used as an initial substance which undergoes high-temperature annealing in the mixture with GeO. Thin-film coatings fabricated from the specified composite exhibit high mechanical durability and climatic resistance; they are transparent in a wide range of spectrum (from 0.6 to 11 m) and have a refractive index of about 2.2. Tests performed in real optical elements (optical sensor element and cutting filter) demonstrated that stabilized germanium monoxide is a promising material for interference optics.

42-48

Authors: H. Lavrenyuk, B. Mykhalichko

The thermochemical parameters (the sum energy of all chemical bonds, the formation enthalpy, and the combustion heat) of burning processes of self-extinguishing epoxy-amine composites modified by copper(II) sulfate occurring in the DGEBA – deta – CuSO4 – O2 system (where DGEBA is bisphenol A diglycidyl ether and deta is diethylenetriamine) have been determined by DFT method. The DFT analysis (the restricted Hartree-Fock (RHF) method with a 6-31G orbital basis set) was performed at the B3LYP level using HyperChem program (version 8.0.6). The calculations confirmed the experimentally established fact that the incorporation of even a little of anhydrous copper(II) sulfate into the framework of epoxy-amine composites ensures a very efficient decrease of their combustibility. The results of the performed thermochemical calculations are in good agreement with the data of thermogravimetric analysis and experimental determination of ignition point and self-ignition point measured for the DGEBA/deta-CuSO4 polymer composite. Thus, anhydrous CuSO4 is a good flame retardant additive that can efficiently suppress the epoxy-amine polymers combustibility.

56-62

Authors: I.P. Olyshevets, V.V. Dyakonenko, S.V. Shyshkina, V.O. Trush, T.Yu. Sliva, V.M. Amirkhanov

Novel anionic coordination compounds of lanthanides with sulfonylamidophosphate (SAPh) ligand of general formula Cs[LnL4] (Ln = La, Nd, Eu, Tb, L- = [C6H5(SO2)N(PO)(OCH3)2]) have been synthesized. The obtained complexes have been investigated by means of 1H NMR, IR, electronic spectroscopies and X-ray diffraction analysis. The compound Cs[NdL4] has been obtained in monocrystalline form. The polymer structure of the complex built from [LnL4]− anions and cesium cations functioning as linkers has been established by the X-ray diffraction analysis and the coordination of ligands in the acidic form via the phosphoryl and sulfonyl group oxygen atoms has been confirmed. The coordination polyhedron of Nd3+ ion was interpreted as a distorted dodecahedron. Based on the analysis of absorption and diffuse reflection spectra, the structures of the closest environment of a central atom in the solution of the complex in acetonitrile and the crystalline state were concluded to be similar.

72-76

Authors: A. Slipkan, N. Shtemenko, R. Bray, H. Obarska-Pempkowiak, A. Shtemenko

One of the important areas of modern science is the selection of the right forms of drug delivery. Layered inorganic nanoparticles, such as zirconium phosphate, have proven themselves well in this area. The study of the properties of these systems and methods of their preparation makes it possible to determine a rational technology of their manufacture, storage conditions as well as suggest a possible mechanism of therapeutic action. The physical dimensions of the formed aggregates, morphology and structure are often the most influential factors for controlling the active surface area, reactivity, bioavailability and toxicity of nanoparticles. Aggregation properties of zirconium phosphate nanoparticles loaded with cluster rhenium(III) compounds with propionate ligands of different structure types (di-, tri- and tetra-carboxylates) and cisplatin were investigated by laser diffraction method in water. It was shown that the quantity and orientation of propionate ligands affect the aggregation properties of the investigated compounds. However, the presence of cisplatin in the composites reduced the aggregation abilities of the nanoparticles which indicate the formation of new complexes on their surfaces. After sonication, cisplatin-rhenium compound composites had practically the same size-distribution curves. Our findings showed that the formation of different complexes with ZrP occurs on the surfaces depending from the structure of the rhenium substances.

84-90

Authors: E.K. Trunova, A.M. Mishchenko, A.A. Rogovtsov, T.A. Makotryk

Due to their valuable properties, coordination compounds of 3d transition metals with aminocarboxylic acids are perspective bioactive compounds. In the present work, potassium (ethylenediamine-N,N'-disuccinato)cobaltate(II) dihydrate was prepared and structurally characterized by single-crystal X-ray diffraction analysis. Structure determination was performed by a least-squares fit of 6669 reflections of highest intensity and refined with the full-matrix least squares procedure. Present compound is a closed-type binuclear Co(II) complex of ethylenediaminedisuccinic acid composed of [(C10H12N2O8)2Co2] moieties bridged via potassium atoms in a zig–zag fashion and possesses the monoclinic Р21/с space group. Each Co(II) ion has a distorted octahedral environment formed by sets of three 5–membered and one 6–membered chelate cycles. One of the positions in the [CoO4N2] octahedron is occupied by oxygen atom of the neighboring ligand molecule. The acetate branches of ligand are situated in the axial positions of the distorted Co(II) octahedron on the contrary to previously studied sodium-containing complex of analogous composition. Each potassium atom has a seven-fold coordination involving three oxygen atoms of water molecules, two oxygen atoms from the nearest carboxyl group and two additional oxygen atoms from two adjacent ligand molecules. The complex under study also displays a developed system of inter–ligand N–HO, C–HO and hydration O–HO bonds.

99-106

Authors: M.V. Chayka, Z.F. Tomashyk, V.M. Tomashyk, G.P. Malanych, A.A. Korchovyi

The chemical dissolution of the CdTe and ZnxCd1-xTe and CdxHg1-xTe solid solutions single crystals in K2Cr2O7–HBr–C4H6O6 (tartaric acid) aqueous solutions has been investigated under reproducible hydrodynamics conditions for the first time. The diagrams "solution composition vs. dissolution rate" have been plotted and the concentration limits of polishing etchant have been determined. The effects of organic component and the nature of the semiconductors on the rate and character of the chemical dissolution were determined. According to the results of kinetics study, the dissolution process of these materials is limited by diffusion stages. The rate of single crystals dissolution grows with increasing the speed of the disk rotation and the etchant temperature. The surface state of the studied semiconductors after chemical dissolution was characterized by means of metallography and atomic force microscopy. The etchants compositions and conditions for realization the chemical-dynamic polishing of these semiconductor single crystals were optimized.

113-119

Authors: D.O. Yelatontsev, V.I. Suprunchuk, A.V. Ivanchenko

The kinetics of adsorption of resinous substances on bentonite clay has been investigated. Natural bentonite clay (NB) was used both without any activation and with the addition of the cationic flocculant Extrafloc P 70 (NB+F). Also, bentonite clay was activated by HCl (AcB) or by NaOH (AlB). It was established that the rate of the adsorption of resinous substances on bentonite clay from the coke wastewaters is determined by external diffusion mass transfer in the initial period of time (1...10 min); then, the kinetics of the process corresponds to the internal diffusion region. The coefficients of external mass transfer of resinous substances to the surface of bentonite clay are stated to be 2.79102 m/s, 2.81102 m/s and 3.17102 m/s for AcB, AlB and NB, respectively. It was shown that the duration of the adsorption of resinous substances significantly depends on the hydrodynamic regime of mechanical mixing of wastewater by clay. It is advisable to carry out the adsorption process at Re10,000, since the desired degree of mixing of wastewater by clay is not achieved at lower values of the Reynolds criterion and there is no further reduction of the purification time at higher values of Re. It is possible to extract 96% of resinous substances from wastewater in static conditions during 3...4 min at optimal doses of bentonite clay (100 mg/dm3) and Extrafloc P 70 (4 mg/dm3).

125-132

Authors: O.V. Perlova, Yu.S. Dzyazko, I.S. Ivanova, О.О. Malinovska, A.V. Palchik

Composite sorbents were prepared by the insertion of inorganic fillers into ion exchange resins. The cation exchange resin was modified by zirconium hydrophosphate; hydrated zirconium dioxide was used to modify anion exchange resin. By means of the method of transmission electron microscopy, it was shown that the fillers are mainly in the form of non-aggregated nanoparticles in the polymer phase. Their sizes are 3–6 nm and 4–20 nm for anion-exchanger and cation-exchanger, respectively. Such inorganic nanomaterials as hydrated zirconium dioxide and the composite, which is based on it and includes also cobalt hexacyanoferrate(II), were also synthesized. These sorbents are characterized by highly developed surface (350–380 m2g–1). It has been found that in all cases the result of modifying is the enhancement of removal of soluble uranium (VI) compounds from nitrate and sulfate solutions where they are in cationic or anionic forms, respectively. The modified sorbents are also characterized by higher sorption rate in comparison with pristine materials. The two-component sorbents were shown to be regenerated more completely and faster. The time of desorption has been found (90–180 min) and the constants of desorption rate for uranile-ions (0.23–5.68)10–4 s–1) have been calculated for regeneration with 0.01–1 М solutions of NaHCO3 and Trilon B. It has been experimentally proved that the initial form of the organic-inorganic cation-exchanger can be restored to 99.5% by 0.1–0.5 М NaHCO3 solution and to 86% by 0.05 М Trilon B solution. The regeneration degree of the organic-inorganic anion-exchanger and modified inorganic sorbents reaches 80 and 90%, respectively, when 1 М NaHCO3 solution is used. The organic-inorganic cation- and anion-exchangers save their high sorption ability towards uranium (VI) compounds during 10 cycles of sorption–regeneration.

139-147

Authors: O.Yu. Fedorenko, L.O. Bilostotska, K.B. Bohdanova, K.S. Polukhina, L.V. Pavlova

The article is devoted to the main features of surface painting of clinker ceramic products by their impregnation with solutions of Co, Mn and Cu metal salts. The intensity of the ceramics color is determined by the type of chromophore (metal cation), the composition and solubility of the salts, the method of solution application and the composition of the furnace environment. It is established that the coloring of clinker ceramic surface is associated with the formation of CoFe2O3, MnFe2O3, CuFe2O3 spinel phases in the course of the firing of products at 1070C. An increase in the microhardness (by 15–20%) indicates that newly formed crystallines contribute to the consolidation and hardening of the surface layer. The analysis of chromaticity coordinates of dark-colored ceramic samples in the system CIE-L*a*b* showed that the color is perceived as really black if the brightness index L<10%. If L10%, then the following tints are visually perceptible: black-brown, smoky-black and black-olive. In order to fabricate clinker products of saturated smoky-black color, it is recommended to impregnate the surfaces of dried semi-finished products with saturated solutions of salts MnCl24H2O, Co(NO3)2 or Co(NO3)26H2O and perform the firing of products under the conditions of a reducing environment.

159-164

Authors: V.L. Cherginets, T.V. Ponomarenko, T.P. Rebrova, A.G. Varich, A.L. Rebrov, Yu.N. Datsko

The behavior of sodium, potassium, rubidium and thallium admixtures during multiple low-temperature crystallization (LTC) of technogenic aqueous solutions of cesium iodide is studied. The effective purification coefficients of cesium iodide solution from alkali metal admixtures () are lower than unity which means the displacing of the said admixtures from the product during LTC. A decrease of sodium and potassium concentrations leads to approaching β values to unity, a similar trend is also observed for the thermodynamic purification coefficients (). High concentrations of sodium admixture result in a decrease in the purification efficiency of cesium iodide solutions from admixtures of alkali metals by LTC method. Rubidium admixture is that which can be most easily removed from the solution of cesium iodide by LTC method. The  value exceeds unity for thallium admixture which indicates the accumulation of this admixture in the product at increasing the number of LTC cycles. Based on the data obtained during 30 LTC cycles of cesium iodide solution, the limit of purification of cesium iodide from potassium admixture is estimated to be 10-5 wt.%. A decrease in the temperature in the freezing chamber from –12C to –14C results in an increase in  values and, hence, in the reduction in the efficiency of the purification of aqueous CsI solutions by LTC method.

12-22

Authors: L. Dubenska, S. Plotycya, M. Pylypets, S. Pysarevska

We have determined that diazonium salts of anaesthesin and novocaine are suitable derivatives for the polarographic determination of these anesthetics. The dependence of the current of the reduction peak of diazonium salts and azo compounds on the concentration of anesthetics is linear with good metrological characteristics. The individual polarographic determination of anaesthesin and novocaine in their mixture in the form of diazo- or azo compounds is not possible because of overlapping the reduction peaks related to individual anesthetics. However, it is possible to determine the total amount of the investigated local anesthetics by summing the heights of the peaks or peak areas of the anaesthesin and novocaine derivatives using the calibration plot as well as the method of additives. The developed methods of polarographic determination of anaesthesin and novocaine in the form of their derivatives were checked by analyzing model solutions and pharmaceuticals (a solution for the injections of novocaine, a combined antiseptic drug "Farysil"). The metrological characteristics of lidocaine determination in the form of 2,6-dimethylaniline diazonium salt are poor, and the method of derivatization is complicated and long-continued.

31-36

Authors: P.О. Nekrasov, О.М. Piven, О.P. Nekrasov, О.M. Gudz, N.О. Kryvonis

The enrichment of fats with omega-3 polyunsaturated acids increases the nutritive value of fats and makes them more health promoting by boosting the immune system and reducing blood coagulability, the level of neutral lipids and the risk of coronary heart disease and atherosclerosis. That is why it is important to develop scientific basis of the synthesis of these lipid systems. There have been created the mathematic model of kinetics of enzymatic glycerolysis of triacylglycerols enriched with omega-3 polyunsaturated fatty acids, enabling quantitative and qualitative assessment of the reaction composition. For the mathematic modelling of the process, a system of nonlinear differential equations has been created which describes the change in the content of the resulting substrates and reaction products through time. To determine acylglycerol composition of the reaction systems, the high temperature gas-liquid chromatography method was used. The simulation was performed using Mathcad 15 environment via the identification of the parameters of the model by means of a random multivariable search algorithm being called a method of complexes, in the course of which the errors between experimental and model data were minimized. The Runge–Kutta method with a variable step of the fourth order of accuracy was used as a numerical procedure for differential equations modelling. As a result of the calculations, the numerical values of the constants of direct and reverse reactions rates and the corresponding equilibrium constants were determined. Based on the received constants of homogeneous substrates mixtures the values of thermodynamic parameters and activation energies of the studied process have been calculated. The conclusions have been drawn about the contribution of each reaction, occurring during biocatalytic glycerolysis of triacylglycerols, to the process under consideration.

46-52

Authors: T. Panchenko, M. Evseeva, А. Ranskiy, Н. Didenko, V. Baumer

The template synthesis of complex compounds has some advantages over other methods, because it allows producing new macrocyclic coordination compounds with valuable practical properties. At the same time, the composition, structure and properties of the final complex compounds depend both on the nature of the metal cation and the presence of reactive centers of the organic ligand. The purpose of this work was to establish the main features of the formation of copper(II) and cadmium(II) complexes with salicylidenesemicarbazone and determine the composition and spatial structure of the synthesized coordination compounds. The paper reports the data on the synthesis of coordination compounds [Cd(Н2L)(H2O)Cl2] (І), [Cu(НL)Cl]2H2O (ІІ), Ba[Cu(L')]2 (ІІІ) and salicylaldazine (ІV) (where Н2L and Н3L' represent salicylic aldehyde semicarbozone and N,N'-bis(salicylidene)semicarbazide, respectively). The synthesis of the investigated coordination compounds was carried out by the interaction of hot ethanol solutions of salicylic aldehyde semicarbazone, МCl2хH2O (M2+=Cd, Cu; х=0; 2) and salicylic aldehyde in a molar ratio of 1:1:1 at the pH value of 9–10 which was adjusted by the addition of Ba(OH)2 dissolved in a water-ethanol mixture (1:1). The composition and structure of the synthesized complex compounds I–III were confirmed by elemental analysis and IR spectroscopy; X-ray diffraction analysis was also used in the case of compounds I, II and IV. The complexation of copper (II) and cadmium (II) salts with salicylidenesemicarbazone under the conditions of template synthesis was investigated. It was shown that the reaction proceeds rapidly with the formation of chloro (salicylidenesemicarbazone) copper(II) dihydrate in the case of copper(II) as a template center; the reaction yields cadmium (II) dichloroaquasalicylidenesemicarbazone complex in the case of cadmium (II). This is due to the template effect of the copper (II) cation, namely, a very significant change in the charge component at potential centers of complexation, which was confirmed by quantum chemical calculations. For salicylaldazine which was separated under the conditions of template synthesis of cadmium (II) complex, the mechanism of its formation with the use of initial salicylidenesemicarbazone and salicylic aldehyde was established.

62-68

Authors: V.S. Farafonov, A.V. Lebed, N.O. Mchedlov-Petrossyan

Properties of the standard solvatochromic Reichardt's dye 4-(2,4,6-triphenylpyridinium-1-yl)-2,6-diphenylphenolate in micelles of n-dodecyltrimethylammonium bromide were investigated by means of molecular dynamics simulations. The characteristics of the location and orientation of the dye molecule as well as the nature of its microenvironment were obtained. These characteristics were compared with those in micelles of cetyltrimethylammonium bromide (CTAB). Deeper immersion of the triphenylpyridium moiety in DTAB micelle was revealed, in accordance with the experimental data. Also, the characteristics of the dye in CTAB micelles of two sizes were compared. They were found slightly different: in bigger micelles, the dye is immersed deeper into the micelle, and is hydrated weaker. The ET(30) polarity parameter of the studied micellar solutions changes in the same order as the hydration of the oxygen atom of dye molecule in corresponding micelles.

76-86

Authors: R.D. Apostolova, Yu.V. Polishchuk

In this article, the results of the research on MnO2 polymorphs as suitable magnesium-inserting cathodic material for the secondary high energy magnesium batteries are critically reviewed. It is shown that MnO2 magnesiation differs from classic type of Li intercalation. Magnesiation of MnO2 can proceed by intercalation or conversion. Conversion with quick loss of the discharge capacity at cycling in "dry" non-aqueous electrolytes is observed in most of MnO2 polymorphs (α-, δ-, closed to γ- phases and OMS-5). Intercalation is more probable in spinel phase. The lack of the electrolyte suitable for effective MnO2 magnesiation is one of the major issues affecting successful realization of high energy Mg battery. Another challenge is slow Mg2+ diffusion in the cathodic host. Water addition to "dry" electrolyte improves MnO2 magnesiation. In this case, magnesiation proceeds through an intercalation-type reaction. However, the water is incompatible with Mg anode. New strategy for increase of the Mg2+ mobility is required. Dual Mg/Li electrolyte and some proposed solutions that could be successful strategies for further development of high energy magnesium batteries are presented.

92-96

Authors: V.I. Goleus, Yu.S. Hordieiev

The lead silicate system underlies many compositions of optical glasses with a high refractive index. Such expensive and rare earth oxides as GeO2, La2O3, Ga2O3, Bi2O3, etc. are also introduced into the composition of these glasses, besides the conventional oxides. The development of new compositions of optical glasses is most frequently carried out by a pilot and experimental method being a labor-intensive process and requiring the considerable material expenses for performing the experimental research. It is possible to appreciably decrease the scope of experiments using the calculation methods of preliminary estimation of the glasses properties. The purpose of this work was to develop the mathematical models of calculation for PbO–B2O3–SiO2–GeO2 based glasses, depending on their composition and optical constants (refractive index nD, mean dispersion (nF–nC) and dispersion coefficient D). In order to establish the interrelation between the optical constants and the composition of multicomponent oxide glasses, the development of mathematical models was carried out using an experimentally statistical method. The developed mathematical models are adequate to the experimental data and allow calculating the optical constants of glasses with the following mean-square deviations: nD=±0.014, (nF–nC)=±11.1•10-4, and D=±0.4. The specified accuracy is sufficient for solution of different practical tasks, which are connected with the selection of compositions of the optical glasses with a preset complex of the optical properties.

102-110

Authors: Ya.A. Kalymon, Z.O. Znak, A.B. Helesh, L.V. Savchuk

The paper presents the results of theoretical and experimental studies on the determination of kinetic characteristics of the absorption process of air oxygen by water in a bubbling mode. As a result of theoretical studies it is shown that the resistance of the mass transfer from the liquid phase exceeds the resistance of the gas phase (2.53...3.42)106 times in a bubbling mode. Therefore, the absorption factor (i.e. mass transfer coefficient) of the oxygen from the gas phase to the liquid phase is equal to the mass transfer coefficient from the liquid phase. With a decrease in the diameter of bubbles from 0.008 m to 0.002 m, the mass transfer rate increases 2.0 times. At low concentrations of oxygen in water (0.1 mol/m3), the rate of absorption increases with increasing the temperature and it decreases at higher concentrations (more than 0.1 mol/m3). It is experimentally determined that the dependences of some kinetic quantities (coefficients of mass output and mass transfer, absorption rates etc.) on the technological parameters correlate with those calculated by criterion equations, but their values are 16…30 times smaller. For slightly acidic waters (pH≤5.5), the rate of the absorption of air oxygen by water in a bubbling mode is higher than the rate of oxidation of Fe2+ ions; therefore, a simple apparatus with a continuous bubbling layer and an average diameter of bubbles of 0.003 m would be effective to remove iron from water. The degree and rate of absorption of oxygen increase in direct proportion to the increase in bubbling height. The findings are of practical importance because they can be used to develop economically feasible methods for the treatment of natural and waste waters, in particular for the removal of iron compounds.

116-124

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

The paper summarizes the results of the study devoted to the use of a new type of film formers, self-dispersing aqueous dispersions of polyurethane ionomers, as binders in pigment compositions for the textile materials printing. A distinctive feature of the polymers of this type is that their macromolecules contain various ionic groups introduced into the main chain of the urethane block-copolymer or the chain extender, in particular, the sulfo- or carboxyl groups. The colloid-chemical properties of aqueous dispersions of polyurethane ionomers of anionic and cationic types were investigated in terms of the physical and mechanical characteristics of polymer films and the quality indicators of printing by pigment compositions in which the dispersions under study were used as binders. It has been shown that polymers from the group of ion-containing polyurethanes having anionic character can be recommended as pigment binding agents. Polymers containing carboxyl groups are more effective as binders among the polyurethanes of the anionic type, because these polymers provide greater resistance to dyes by wet treatments, a milder stamp of printed textiles and stable printing results. A higher intensity of colors was observed which are formed with the use of carboxyl-containing polymers due to the lower polymer ability to microphase separation. This property is manifested in the heat treatment of printed textile material by the clouding of polymer films, which results in a decrease in the intensity of coloration. It has been shown that more intense and stronger colors are formed by using of cationic polymers as compared with the anionic ones (but the latter cannot be used due to their high coagulation ability as binding agents). Cationic polyurethanes can be recommended to be used with special equipment, for example, when printing on fabrics using airbrushes.

131-139

Authors: S.P. Rogalsky, V.V. Davydenko, O.V. Dzhuzha, O.P. Tarasyuk, L.G. Lyoshina, O.V. Bulko, V.I. Parkhomenko, O.A. Aksenovska

In this work, imidazolium ionic liquid was tested as a potential plasticizing and antimicrobial additive to polyvinyl chloride (PVC). The new hydrophobic liquid salt 1,3-dihexylimidazolium dioctyl sulfosuccinate (C6C6IM-DOSS) was synthesized. The composite PVC films containing 20, 30 and 40 wt.% of ionic liquid were prepared. According to thermal gravimetric analysis data, PVC/C6C6IM-DOSS composite is thermally stable to at least 190С that indicates its availability for the processing by conventional methods. It was found by differential scanning calorimetry that the ionic liquid has a noticeable plasticizing effect on PVC, decreasing its glass transition temperature from 83.5С to 44.8С at the content of 20 wt.%. An increase in content of ionic liquid to 30% did not cause further changes of glass transition temperature. Thus, the results of differential scanning calorimetry indicated the availability of the ionic liquid as a secondary plasticizer for PVC. It was revealed that C6C6IM-DOSS possesses excellent migration resistance that was about 1% after 42 days. The results of microbiological study showed high antibacterial activity of PVC films containing 3–4 wt.% of the ionic liquid against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria.

149-153

Authors: V.G. Sozontov, B.M. Shukaylo, V.M. Moskalyk, V.V. Kazakov, O.V. Suvorin

This report summarizes the results of the study devoted to the main features and mechanism of the fabrication nitrogen oxides by various methods and their interaction with water solutions of urea (carbamide) and ammonium nitrate. The results of thermodynamic calculations revealed that the interaction of carbamide with ammonium nitrate proceeds with the heat release under certain conditions and the reaction equilibrium is shifted to the right side. The degree of transformation of initial reagents into the final products reached 100%. To create favorable conditions for the beginning of the interaction of urea with ammonium nitrate, the catalysts, nitrogen oxides, should be introduced into the mixture, these oxides being prepared by the reaction of copper with nitrate acid. The equilibrium constants of the decomposition reactions of ammonium nitrate were calculated, their values indicated shifting the equilibriums to the right side; the degree of decomposition of components reached 100% at the temperature of 2703500C. It was theoretically established that the interactions of nitrogen (I), (II) and (IV) oxides with urea occur with the release of a large amount of heat and their chemical equilibriums are completely displaced to the right side.

161-167

Authors: Khlibyshyn Yu.Ya., Pochapska I.Ya., Grynyshyn O.B., Gnativ Z.Ya.

This work reveled the effects of the ratio of acid tar coupled with straight-run petroleum tars, the temperature of the process, the specific delivery rate of acid tar to the reactor, the rate of temperature elevation in the reactor the final heating temperature of the bitumen mass in the reactor and the stirring intensity of the reaction mixture in the reactor on the quality and properties of the bitumen prepared from the acid tar. The experimental findings confirmed that sulfur compounds, particularly sulfonic acids, are reduced to elemental sulfur. However, an intermediate product (i.e. hydrogen sulfide) was found only in small quantity. It was determined that the maintenance of a certain delivery temperature of reagents and a speed of their movement allows avoiding vigorous vapor evolution and excessive growth of the reaction volume, especially due to foaming. It has been shown that the initial temperature in the reactor has a little effect on the main quality factors of bitumen (such as the softening point, ductility, penetration, solubility in benzene, and the content of water-soluble compounds, acids and alkalis in bitumen); however, it significantly influences the process flow.

14-18

Authors: A.A. Kityk, Y.D. Rublova, N.G. Bannyk, V.S. Protsenko, F.I. Danilov

The paper describes the effect of electropolishing on the corrosion rate of mild steel in a deep eutectic solvent Ethaline (a eutectic mixture of choline chloride and ethylene glycol). Electrochemical polishing was carried out both in "pure" solvent Ethaline and in Ehtaline with the addition of water (10 vol.%). The rate of steel corrosion was measured using electrochemical impedance spectroscopy. It was shown that electropolishing of steel leads to a decrease in its corrosion rate. The influence of the polishing current density and bath temperature on the corrosion rate was determined. An analysis of the obtained results showed that the rate of corrosion was decreased both by reducing the true surface area of the samples and by reducing the reactivity of the metal surface in the anodic half-reaction. Optimal electropolishing conditions were established under which the highest reduction of the rate of corrosion of mild steel in Ethaline was achieved.

27-35

Authors: T. Luk'yanenko, A. Velichenko, V. Knysh, O. Shmychkova

It is shown that the process of lead dioxide electrodeposition can be described by a four-stage kinetic scheme in which the electroactive particles are methanesulfonate complexes of lead with different composition. The initial stage of the process is the electrooxidation of water with the formation of oxygen-containing particles of radical type OH•ads on the electrode surface. Considering the water concentration in aqueous solutions and the fact that the hydroxylation of the electrode surface occurs at much lower potentials than the processes of oxygen evolution and oxidation of lead compounds, this stage is fast. Then the chemical stage of oxidation of [Pb(CH3SO3)]n(2n)+ by oxygen-containing radicals OH•ads occurs with the formation of the unfixed on the electrode surface Pb(III) hydroxo complexes [Pb(CH3SO3)n(OH)](2-n)+, which are subsequently oxidized in the electrochemical stage of charge transfer. At low polarization, this stage is rate-determining. The extremal dependence of the reaction rate on the concentration of methanesulfonate ions observed in this case is due to the simultaneous action of two oppositely directed factors: a decrease in the charge of electroactive particles and the surface of the electrode on the one hand, and the effect of inhibition by specifically adsorbed methanesulfonate ions, on the other. In the last stage of the process, the hydroxo complexes of tetravalent lead decay by chemical mechanism with the formation of lead dioxide. At high polarization, the rate-determining step of the process is the delivery of lead complex ions to the electrode.

43-47

Authors: E.V. Potapenko, P.Y. Andreev, I.P. Isayenko

A process of catalytic oxidation of 4-nitrotoluene with ozone was studied in the system (CH3CO)2O – CCl3CO2H in the presence of Co(II) acetate. It is shown that 4-nitrobenzaldehyde can be obtained in the form of acylale at 20C with a yield of up to 78%. The kinetic parameters of the main stages of the catalytic cycle have been established and a reaction mechanism has been proposed according to which ozone initially reacts with Co(II) acetate, and the direct oxidation of the methyl group of the substrate occurs in the reaction with the oxidized form of the metal. The optimal ratio [ArCH3]/[Co (II)] = 2 was determined experimentally. A further increase in the concentration of the catalyst influences neither the rate of oxidation nor the selectivity of the reaction. The role of trichloroacetic acid is not limited to the catalysis of the acylation reaction of alcohols and aldehydes that are formed during the oxidation process, but significantly affects the reactivity of Co(III). An increase in temperature promotes a real increase in the selectivity of oxidation. However, there is an increase in the depth of oxidation under these conditions and the main product of the reaction is 4-nitrobenzoic acid.

59-68

Authors: O.Ya. Smirnova, I.P. Polyuzhyn, Yo.Yo. Yatchyshyn

This paper investigates the chromatographic characteristics of seven amino acid derivatives of 3-chloro-1,4-naphthoquinone under conditions of normal-phase thin-layer chromatography. The dependences of the retention parameters of compounds on the composition of the binary mobile phase are obtained; the mobile phase is based on benzene, and chloroform, acetone, acetonitrile, methanol and propan-2-ol are used to enhance the elution ability at concentrations ranging from 2.5 to 10% v/v. It is shown that the experimental data on the retention of the investigated compounds as functions of the concentration of the polar component in the eluent are well described in logarithmic coordinates of the linear Soczewinski equation. The slope of these dependencies satisfactorily correlates with the area occupied by the adsorbed analyte molecule on the stationary phase, and the intercept also depends on the nature of polar component of the mobile phase. The calculation of the area occupied by the adsorbed analyte molecule on the stationary phase is performed according to the Snyder scheme.

77-81

Authors: N.Yu. Strutynska, O.V. Livitska, N.S. Slobodyanik

The features of the formation of cesium-containing calcium phosphates were investigated in the course of their precipitation from aqueous solutions in the presence of sodium or potassium cations with the subsequent heating of the obtained samples at 700C to convert them to the form of ceramic materials. According to the results of energy dispersion X-ray spectroscopy, CHN analysis and powder X-ray diffraction, the formation of apatite-related Cs+, MI, CO32- -containing calcium phosphates (MI – Na, K) was observed. It was determined that the content of Cs+ cations in prepared samples increased with increasing the amount of carbonate ions and in the presence of potassium cations in the initial solutions. The results of the thermal analysis confirmed the stability of Cs+,K+,CO32--containing calcium phosphates as regards the losing of carbonate at their heating to 900C. The established conditions of the preparation of cesium-containing apatite-type phases can be assumed as a basis of the development of the processes of the removal of radioactive cesium from aqueous solutions and its immobilization into stable phosphate matrices.

92-96

Authors: V.I. Goleus, Y.S. Hordieiev, A.V. Nosenko

Low-melting lead borosilicate glasses are used in electrical engineering and instrument making to manufacture hermetic ceramic-metal junctions. Thus, there is a need for the development of glass cements to produce junction at temperatures lower than 450C. In this regard, the formation conditions and the properties of glasses were investigated, the content of the components was as follows (mol.%): PbO 30–56, ZnO 5–20, B2O3 15–40, and SiO2 5–25%. The glasses of this composition were melted in platinum crucibles at a temperature of 850–900C for 30 minutes. The initial materials included silica sand, boric acid, zinc oxide and lead oxide. Glasses obtained in this system possess physicochemical properties varying in a quite wide range. The dilatometric softening temperature of glass varied in the range of 290–430C, the coefficient of linear thermal expansion varied in the range of (78–117)10-7 К-1 and the density varied from 4.9 to 6.7 g/cm3. The generalization of the dependence of the properties of glasses on their chemical composition was carried out using additive formulas for which the partial contributions of oxides to the values of the corresponding properties have been determined by experimental and statistical methods. It was found that very good wettability and spreadability at temperatures of 450–500C on the surface of aluminum oxide ceramics are typical of the glasses with a dilatometric softening temperature of no more than 340C and with the lowest crystallization ability. The chemical composition of the glasses, which are the most promising for obtaining ceramic-metal junctions at a temperature of 450°C, is limited to the following contents (mol.%): PbO 48–55, ZnO 5–14, B2O3 25–35, and SiO2 5–15.

103-109

Authors: V.A. Kucherenko, Yu.V. Tamarkina, I.B. Frolova

The thermolysis (≤500C) of five anthracites ANs (C 94.6–95.6%) impregnated with hydroxides MOH (M = Li, Na, K, Rb, and Cs) at MOH/AN ratios of RМOH≤20 mmol/g was investigated. Using the thermoprogrammed gravimetry (5 deg/min, OD-103 MOM derivatograph), the weight loss (Δm) was determined as the yield of volatile products and the rate of their formation (ωm) was estimated. It has been established that the thermal dehydration (≤200°С) and the formation (>250°С) of volatile organic products (VOPs) are observed as a result of parallel thermal and alkaline destruction when heating AN and "AN-MOH" compounds. The thermodehydration does not depend on the AN type, but is influenced by MOH and manifested by three peaks at 82–92°C, 138–147°C and 158–160°C related to H2O associated with the following: (1) organic coal substance, (2) MOH molecules, and (3) complexes "M+--system of polyarene". For all ANs, the effect of MOH is observed at 250–500°C (RMOH≤2 mmol/g) and results in an increase in the VOPs yield (from 1% to 5–6%) and a decrease in the effective activation energy (from 230–250 to 110–170 kJ/mol). It was proposed to estimate the alkaline thermal destruction contribution as the following difference in rates: Δm=m(AN-MOH)–ωm(AN). The obtained data allowed drawing the following conclusions: (1) the alkali promotes thermal destruction, (2) the maximum of Δωm value and the beginning of the VOP formation decrease by 50–80°C, and (3) the alkali reactivity increases in the range: LiOH

120-128

Authors: N.V. Nikolenko, I.S. Samchileev, A.V. Dubenko

The kinetics of ammonical leaching of molybdenum from the spent iron-molybdenum catalyst of Perstorp Formox under mechanical and ultrasonic conditions is studied. The process is shown to proceed in the intradiffusion mode, as in a fixed-bed flow reactor. The mechanical influence on the catalyst particles was modeled by continuously mixing of the suspension by the propeller stirrer (with a surface area of 2 cm2) at a rotation speed of 300 min-1 in a round-bottomed flask. The flask was placed in an ultrasonic bath filled with water at a frequency of 22 kHz and an intensity of 0.4 W cm-2. We used the "shrinking core" model which was modified for low-dissociation reagents by us as a mathematical model of the investigated process. The rate-determining step of the leaching process is the diffusion of hydrated ammonia molecules through the layer of the reaction product, ferric hydroxide. To confirm this conclusion, the apparent activation energies of the leaching process were determined using ammonia, soda and alkali, which were 21.3, 6.0 and 1.5 kJ mol-1, respectively. The difference in the values of activation energies is well explained by the fact that the rate-determining step of the process is the diffusion of hydroxide ions in solutions of alkali and carbonate ions in soda solutions. The effect of increasing the time of complete conversion of the catalyst particles for concentrated ammonia solutions is established, which can be caused by decreasing the diffusion coefficient of ammonia molecules or increasing the molar density of the iron hydroxide film. According to this effect, we conclude that an increase in the concentration of ammonia solution at the decomposition of iron molybdate above 2 mol L-1 has no significant advantages. For example, when using 13.5 M ammonia solution, the total conversion time is 39 minutes. But when using 2 M solution, the time is 52 minutes, i.e. only 1.33 times more. Therefore, the use of highly concentrated solutions of ammonia is not rational for the leaching of molybdenum from a raw material containing ferric irons.

135-141

Authors: U.V. Khromyak, V.Ye. Levytskyi, K.V. Stepova, V.Y. Skorokhoda

The influence of monomer nature (vinyl acetate, methyl methacrylate and styrene), concentration factors, temperature and mixing rate on the kinetics of the emulsion polymerization of vinyl monomers in the presence of polyvinylpyrrolidone has been investigated. The rational technological parameters of copolymer synthesis have been established. It has been determined that the properties of emulsion polymerization of latexes (surface tension, pH and particle radius) depend on the conditions of the process; the ratio of monomer to aqueous phase, temperature, concentration of monomer and initiator, and also the amount of polyvinylpyrrolidone. The polyvinylpyrrolidone-grafted copolymers that have been synthesized by emulsion polymerization have been used as a polymer matrix for the preparation of methyl methacrylate-copolymer compositions. Block polymerization of methyl methacrylate in the presence of polyvinylpyrrolidone copolymers occurs at a high rate and, depending on the nature of the polymer matrix, the monomer conversion rate of 70–90% is achieved within 10–15 minutes. The highest polymerization rate and the maximum degree of conversion are observed when using a grafted copolymer of polyvinylpyrrolidone with methyl methacrylate. The modified materials obtained on the basis of the developed compositions are characterized by sufficiently high operational properties, such as surface hardness, heat resistance and strength of adhesive bonds to supports of different nature.

148-152

Authors: Ya.O. Shablovsky, V.V. Kiselevich

The possible solution of the classical problem of correct determining the glass transition temperature of polymers is proposed. The equation for the correlation between the glass transition temperature and the cooling rate of polymeric glass-forming media is suggested on the basis of combination of thermodynamic formalism and the ideas of relaxation kinetics. The parameters of that kinetic equation are determined and tabulated for a number of glass-forming substances covering sufficiently wide class of pure and modified polymers, in particular polyvinyls, polyesters, and polydienes. The possibility of the manifestation of an anomalous dependence of the glass transition temperature on the cooling rate is substantiated. It is suggested that the observable anomalies in the kinetics of the glass transition arise from considerable inertance of the segments of polymeric macromolecules, i.e. are of threshold nature.

14-17

Authors: V.A. Galaguz, S.M. Malovanyi, E.V. Panov

Raman spectra were obtained for two samples of the composite based on synthesized lithium iron phosphate powders. The first sample contained some traces of the reaction medium, and the second one was a thoroughly washed powder. In the obtained experimental spectra, well-visible D and G bands were observed which are characteristic for disordered carbon. The decomposition of the spectra into the Gaussian-Lorentz components allowed assessing the quality of the carbon coating of a LiFePO4/C composite obtained by pyrolysis of glucose and organic components of the reaction medium. The estimation of the ratio of peak intensities of the D and G bands of the powdered composite (ID/IG = 0.77) and the powder with residues of the reaction medium (ID/IG = 1.56) as well as the approximate calculation of the sp2/sp3 carbon ratio (3.95 and 1.35, respectively) shows the negative effect of the products of pyrolysis of the organic reaction medium on the quality of the carbon coating of the composite. The electrodes fabricated from the LiFePO4/C composite based on the washed powder with a carbon coating obtained after glucose decomposition demonstrate the reversibility of the process of lithium intercalation/deintercalation, and a stable plateau on the charge/discharge curves is observed. The material capacity is 135 mAhg-1 for 0.1 C. This is a quite satisfactory index and it confirms the presence of a conductive carbon coating on the surface of the LiFePO4 crystals.

25-30

Authors: S.V. Zubkov, А.V. Mazepa, V.O. Gelmboldt

Iron (II) coordination compounds with Schiff bases exhibiting different types of biological activity are of interest as potential drugs. The results of synthesis and study of the structure of iron (II) complexes with aminoguanizone of isatin (L1H) and nitroaminoguanizone of isatin (L2H) are discussed. The Schiff bases were obtained by the reaction of condensation of isatin with the corresponding guanidine derivatives. Iron (II) complexes were synthesized by the interaction of FeCl24H2O with Schiff bases L1HHCl and L2H in ethanol medium; the synthesis was carried out in neutral and alkaline media. The product of the reaction of iron (II) with the molecular form of the L2H ligand was not obtained, which was due to the electron-withdrawing effect of the nitro group of the ligand. The composition and the probable structure of the synthesized complexes [Fe(L1Н2)2Cl2]Cl2 (yellow), [Fe(L1)2] and [Fe(L2)2] (both green, the yields are 46% and 54%, respectively) are determined by elemental analysis, conductivity, IR and electron spectroscopies, and the data on static magnetic susceptibility. Coordination compound [Fe(L1Н2)2Cl2]Cl2 was also characterized by FAB mass-spectroscopy. From the obtained data of spectral and magnetochemical measurements, one can conclude that the complexes have a bis-chelate structure with an octahedral and square-planar configuration of the coordination polyhedra FeN2O2Cl2 and FeN2O2, respectively. It is planned to study the pharmacological activity of the synthesized compounds.

37-43

Authors: M.I. Nagornyak, V.V. Oleksa, S.I. Vynnytska, I.A. Dron, B.O. Chekh, V.Ya. Samaryk, S.M. Varvarenko

This article describes the results of our research of the modifications of polysaccharides by N-derivatives of glutamic acid using Steglich esterification. It is known that the modifiers of polysaccharides are widely used as polymers of medical and biomedical applications. Among them, the modifiers with the structured architecture of macromolecules have an important place. The use of N-derivatives of glutamic acid as a structuring agent allows obtaining biodegradable and non-toxic polymeric materials without any toxicity of biodegradation products. The dependence of the efficiency of this process was considered and the structure and composition of the obtained reaction products were investigated. It was shown that the reaction successfully proceeds with the participation of both carboxyl groups of N-derivatives of glutamic acid which leads to the structuring of macromolecules of polysaccharides under mild conditions. The study of the properties of the obtained modifiers as well as the investigation of their structure and composition by NMR spectroscopy showed that two different structure-based polymers–macromolecules with branched and spatially structured architecture are formed in the reaction mass. On certain conditions of obtaining, these products are microhydrogels, when they are being dispersed in water. Polymers with branched-chain of macromolecules forms self-stabilized dispersions in aqueous media. Thus, the article gives the results of the research of new polymers of medical purpose.

50-57

Authors: O. Shmychkova, T. Luk'yanenko, L. Dmitrikova, A. Velichenko

The electrochemical oxidation of 4-chlorophenol on lead dioxide anodes micromodified by ions of iron group has been investigated. As follows from the data obtained, the rate of oxidation of organic substances on the anode materials involved is proportional to the number of reactive oxygen species in the near-electrode zone (OH–radicals) formed during the electrolysis as intermediates in water oxidation and participating in subsequent homogeneous chemical reactions with organic substrates in the bulk. The O1s peak on X–Ray photoelectron spectra was used to evaluate the amount of inert and labile oxygen-containing particles on undoped and doped PbO2. Doping of lead dioxide with nickel leads to a significant increase in the number of labile oxygen-containing particles on the surface of the electrode, while iron modification leads to the opposite effect − an increase in the amount of inert oxygen-containing particles. The anodic oxidation of 4-chlorophenol yields a rather large number of intermediate products. The main intermediates include benzoquinone and maleic acid which was confirmed by high-performance liquid chromatography. The micromodification of lead dioxide with metal ions of iron group leads to a significant change in the electrocatalytic activity of oxide materials. The activity grows in the following sequence of modifying ions: PbO2  Co-PbO2  Fe-PbO2  Ni-PbO2.

64-69

Authors: Z.O. Znak, Yu.V. Sukhatskiy, R.V. Mnykh, Z.S. Tkach

The authors analyzed the data concerning the process of water sonolysis in cavitation fields, according to which the radicals generated in the cavitation fields are recombined with the formation of hydrogen, oxygen, water, hydrogen peroxide, etc. It was established that water saturation by oxygen occurs during cavitation, and oxygen plays an important role in the purification of water heterogeneous environment from organic compounds; the degree of saturation of water by oxygen was 67.2% of the maximum possible value after 450 s, which corresponds to the concentration of oxygen in water of 6.48 mg dm-3. The amount of energy consumed for the formation of free radicals was calculated on the basis of the results of cavitation saturation of water by oxygen and thermochemical calculations of the process of water sonolysis (in particular, using the Kirchhoff formula and the Meyer-Kelly equation). A fraction of the energy from the aqueous environment in the form of acoustic oscillations, which is spent directly on the sonolysis of water was estimated by the value of the chemical-acoustic coefficient of utility which was equal to 2.55810-3 for water sonolysis in a hydrodynamic jet cavitator. It was found that this value is at least 1.7 times greater than that of ultrasonic emitters, which indicates a higher energy efficiency of hydrodynamic cavitators compared to ultrasonic ones.

79-89

Authors: V.I. Ovcharov, К.М. Sukhyy, L.А. Sokolova, V.L. Kalinyuk, O.A. Tertyshnyy, L.R. Yusupova, E.A. Belyanovskaya

The characteristics of the products of rice husk (RH) after its thermal treatment are determined, these products being fine dispersed silicon- and carbon-containing powders with amorphous-crystalline structure. The comparative evaluation and experimental verification of possible application of wide range products produced during various conditions of the thermal treatment of crashed rice husk as fillers of elastomeric compositions based on carbon-chain diene rubber are performed. The introduction of 20 phr (parts per hundred rubber) of either the product of carbonized or silicon dioxide obtained by the thermal treatment of rice husk is shown to have a positive effect on both plastic and viscous properties of rubber mixtures based on butadiene-styrene rubber SKS-30 ARK, as well as on the relative extent of cross-linking, the formation of cross-links between rubber and filler during vulcanization and the kinetic parameters of sulphuric vulcanization. This positive effect is observed in this case as opposed to the known semi-enforcing compositions. The semi-enforcing effect of fillers obtained from RH is stated to provide the vulcanizates with high values of equilibrium shear modulus, temperature and heat resistivity as concerns the resilient strength properties relative to the effects of known fillers. The complex of the properties of elastomeric compositions is strongly affected by time-temperature regime of the production of RH.

96-104

Authors: O.V. Savvova, S.M. Logvinkov, O.V. Babich, А.R. Zdorik

The paper characterizes the topical issue of the development of competitive high-strength lightweight mullite-cordierite glass-crystalline materials as hinged armor elements for increasing the reliability of the protection of special equipment which is exploited under conditions of high temperatures and mechanical loads. The aim of this work is to establish the characteristics of the change in the phase composition of magnesium aluminum silicate glass ceramic materials under heat treatment; this will allow selecting the optimum temperature-time conditions for the heat treatment and synthesizing glass ceramic materials with enhanced thermal parameters. The work substantiates the choice of a system, crystallization catalysts and modifying components to obtain high-strength magnesium aluminum silicate glass ceramic materials based on crystalline phases of mullite and cordierite. The compositions of model glasses based on MgO– Al2O3–SiO2 system in the temperature range of 1550 to 1600С were synthesized and the area of glass formation was investigated. The dependence of the crystallization ability on the content and the type of phase-forming components in glass materials is experimentally determined. A sequence of the formation of metastable crystalline phases and temperature-time conditions for the formation of solid solutions based on -cordierite and(or) mullite is established. The factors are revealed that determine the formation of the glassceramic structure of magnesium aluminum silicate glass ceramic materials under the conditions of low-temperature two-stage thermal treatment.

113-120

Authors: М.І. Skiba, О.А. Pivovarov, А.К. Makarova, V.D. Parkhomenko

A simple method has been developed for the preparation of silver nanoparticles (Ag NPs) based on the use of discharged plasma in the presence of a stabilizer (polyvinyl alcohol, PVA). The UV–vis spectrum of AgNPs/PVA exhibited a broad surface plasmon absorption around 400–440 nm which originated from the formation of Ag NPs. The effects of different Ag+ concentration, the amount and the molecular weight of PVA and the duration of treatment with plasma discharge upon UV-visible absorption spectral characteristics of silver nanoparticles have been studied. The content of PVA in the reaction medium (1.25–10.0 g L-1) is sufficient for nanoparticles stabilization, depending on the initial concentration of Ag+ (0.04–0.5 g L-1). The obtained results show that the average size of the silver nanoparticles decreases with increasing the amount of PVA in the solution, but increases with increasing its molecular weight. Plasma action during 5–6 minutes provides formation of silver nanoparticles for the investigated range of Ag+ concentration. Characterization of AgNPs was made using scanning electron microscopy, X-ray diffraction and zeta potential analysis. The results indicated the formation of spherical, nanometer-sized particles. XRD analysis revealed that the particles were face-centered cubic. Nanoparticles thus prepared are found to be stable in aqueous solution over a period of two months at room temperature.

127-133

Authors: J. Tamilarasi, C. Joseph Kennady, K. Velmurugan

Newly synthesized 3-(1H-benzo[d]imidazol-2-yl) quinolin-2-thiol derivative (BIQTH) was studied as a corrosion inhibitor by using a weight loss method and electrochemical methods. The weight losses of mild steel samples proved that BIQTH is an efficient corrosion inhibitor for mild steel in 1 M HCl at the temperature of 28C. The corrosion rate of mild steel in 1 M HCl was decreased with increasing concentration of inhibitor. Potentiodynamic polarization studies indicated that BIQTH inhibitor displays predominantly a cathodic type of inhibition. AC impedance measurements showed that larger values of charge transfer resistance and lower values of double layer capacitance with change in the concentration of the inhibitor resulted from the adsorption of the inhibitor molecules and the formation of a protective layer on the mild steel surface. The adsorption of inhibitor obeyed Langmuir isotherm. The surface morphology of the mild steel in the presence of the inhibitor was studied by means of scanning electron microscopy.

16-23

Authors: L. Dmitrikova, O. Shmychkova, S. Zagorulko, T. Luk'yanenko, A. Velichenko

The electrochemical oxidation of substituted phenoxy acetic acids on lead dioxide anodes micromodified by bismuth has been investigated. It has been established that the polarity of the substituents in phenoxyacetic acids does not affect the efficiency of the hydroxylation process. Electron-acceptor substituents as well as electron-donors direct the attack of hydroxyl radicals into para-positions. The conversion time required for the oxidation of the herbicides to the aliphatic compounds in most cases depends on the number of substituents in the aromatic ring and is almost independent of their nature. Oxidation occurs according to the radical mechanism of ipso-substitution in aromatic compounds when attacked by OH radicals and proceeds through the formation of corresponding phenol; subsequent oxidation leads to the formation of corresponding benzoquinones through hydroquinones that has been confirmed by high-performance liquid chromatography. Subsequent hydroxylation of the aromatic ring is accompanied by its cleavage and the formation of aliphatic carboxylic acids, which is further completely mineralized to CO2 and H2O.

30-38

Authors: S.B. Meshkova, N.T. Pokhodylo, P.G. Doga, O.Y. Shyyka

In this paper, the conditions for the formation and luminescence of Eu3+ and Tb3+ complexes with synthesized pyrazolin-5-one derivatives containing β-diketone groups was investigated. The evaluated values of the triplet level energy of ligands (ET1) revealed the possibility of its transfer to the central Eu3+ ion from all ligands in the excited state, while this transfer to the Tb3+ ion is possible only in complexes with two ligands in which ET1 values are higher than the emitting level of Tb3+ ion. It was determined that the 4f luminescence intensity of Eu3+ and Tb3+ complexes depends on the energy gap (E) between ET1 and the energy of the emitting level of the lanthanide ion. The luminescence intensity of Eu3+ and Tb3+ complexes decreases as compared with the optimal energy gap both at low values of E and at very high values of E. An increase in the luminescence of the solutions of Eu3+ and Tb3+ complexes by an order of magnitude and more was established when the second ligand, 1,10-phenanthroline, has been added to them. The addition of triphenylphosphine oxide and trioctylphosphine oxide is less effective possibly due to the higher steric hindrances that they create for coordination with the central ion. The coordination of Ln3+ ions with the functional groups of the ligands was confirmed by IR spectra of complexes in a solid state.

46-50

Authors: N.V. Toropin, Y.V. Trush, B.V. Murashevich, K.S. Burmistrov

New reactions of arenalazines 1,4-benzoquinones with potassium thiocyanate in acetic acid were investigated. It was established that the reactions proceed via the 1,8-addition scheme, similar to that described earlier for hydrohalogens and amines of different nature and in contrast to other type of quinoneimines which react with hydrochloric acid, potassium thiocyanate and other nucleophilic agents according to the 1,4-, 6,3-, 1,6- or 6,1-addition scheme. The addition product of potassium thiocyanate is spontaneously cyclized with the formation of the derivatives of 5-mercapto-1,2,4-triazoles with a good yield. The alkylation of these triazoles with equimolar quantity of dimethylsulfate leads to S-methyl derivative; a threefold excess of dimethylsulfate yields dimethylated product. The structures of the obtained compounds were confirmed by 13C, 1H NMR and IR spectroscopies. The synthesized mercaptotriazoles can be used as inhibitors of metal corrosion, as well as components of drugs with cytostatic, antibacterial, immunopotentiating and hepatoprotective activities.

60-69

Authors: R.D. Apostolova, R.P. Peskov

The analysis of galvanostatic curves, cyclic voltammograms and impedance parameters was performed in order to determine and interpret the key factors responsible for the decrease of the discharge characteristics of thin-layer composite Co-doped LiMn2O4 spinel–carbon nanotubes (CNT) electrodes in redox reaction with lithium during continuous cycling at low temperature and high charge-discharge rate. The comparison of galvanostatic curves and cyclic voltammograms obtained by using three-electrode and two-electrode experimental cells was carried out; the impedance spectra as functions of temperature and charge-discharge rate were considered too. This allowed following the evolution of degenerative electrode processes without the usage of research techniques which are complicated and not accessible enough. The charge transfer through the solid-electrolyte interface between solid-electrolyte film/spinel composite, complicated by diffusion of Li+ ions in composite bulk, plays a key role in decreasing the discharge characteristics of Co-doped LiMn2O4 spinel composition with CNT at low temperatures and continuous cycling. It was established that the processes of anodic decomposition of the electrolyte starting at 4.13 V vs. Li/Li+-electrode and low conductivity of electrolyte EC, DMC, 1 mol L-1 LiClO4 at low temperatures (258 K) have a negative influence on the effective electrochemical performance of accumulator system LiCo0.04Mn1.96O4, CNT-electrodes/electrolyte/Li. A further optimization of the electrolyte with the use of some efficient additions to the developed spinel composite can be a possible way to improve the electrode performance. A decrease in the conductivity of LiMn2O4 spinel results in a decrease in the capacity at low temperature (258 K). The modification of the spinel composite seems to be very promising to suppress its low-temperature phase transitions. The elimination of the established reasons for decreasing the capacity will facilitate the realization of new promising LiCo0.04Mn1.96O4–CNT electrode material in lithium ion accumulators.

79-85

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

The effects of temperature-time conditions of the heat treatment (the temperatures of loading, sintering and removal from the furnace and the duration of exposure at a maximum temperature) of porous glass-crystalline materials containing 15% loam as a gas-forming agent on their structure were investigated in this work. The change in volume of the burned samples was determined and the diameters of the pores were measured. The coefficients of bloating and inhomogeneity of the structure were calculated, and the type of structure, which depends on the average diameter of the prevailing pores, was analyzed. In order to obtain materials with a medium porous structure (prevailing pore size of 0.5–1 mm), when loam is used as a gas-forming additive, the temperature of their placing in the furnace should be 600C, followed by its raising to a maximum value (750C) and a further isothermal exposure for 60 minutes. The advantages of the application of the chosen gas-forming agent were shown; they are due to its influence on the rheological properties of the pyroplastic glass-mass and the stabilization of the porous structure of the material during the cooling process. These allow avoiding the stage of sharp cooling after the firing and simplifying the manufacturing technology.

95-100

Authors: Ryzhova O.P., Kislichnaya R.I., Nagornaya T.I.

A review of the literature on colorimetry showed that color is one of the indicators of aesthetic evaluation of the quality of materials and products used for various purposes. At the same time, the accuracy of determining the color characteristics enable to more objectively evaluate the quality of the material. In connection with this, the improvement of metrological support for color measurements is very relevant both for the production of colored materials themselves and for assessing their color stability in the maintenance under the influence of various factors. It is expedient and promising to use new materials to create reference sets of color and chromaticity measures, such as enamel plates of different color tones. As a result of our study, new reflecting measures of color based on various types of glass-enamel coatings on metal designed have been developed which are appropriate to the calibration of colorimeters and comparators. Optimum concentrations of coloring components and other mill additives have been established to obtain glass-enamel coatings with the specified color characteristics. The permissible absolute errors of the sets of measures were determined to be ±0.3 (with respect to the color coordinates) and ±0.002 (with respect to the chromaticity coordinates).

109-114

Authors: A.L. Sokolskii, K.G. Kovalenko, V.I. Sivetskii, E.P. Kolosova

In this paper, we present the procedure and results of refined design calculations of die (extrusion) heads intended for shaping profile products of polymeric materials. The effects associated with the change in shape and size of the profile after exiting the die head are taken into account in calculations. The polymer is considered as a viscoelastic fluid. The aim of the simulation is to determine the geometric shape of the head channel, which will result in a balancing of the outflow costs from the head and ensuring the condition for obtaining the given product profile. The modification of the channel shape by using the optimization algorithm allows calculating the geometry of the forming channel of the heads for the given sizes of the extruded articles. To solve the inverse extrusion problem, the Fletcher-Reeves algorithm is implemented, which is used in determining the geometry of the head forming channel to provide the desired shape of the extruded profile. To describe the dependence of the shear rate on the viscosity of the material being processed, the Berd-Carro model is used. The developed method allows solving the inverse problem of the process of extrusion molding of continuous products; that is to say, it makes it possible to design the necessary configuration of the die head if the properties of the thermoplastic material to be processed and the geometric parameters of the extruded product are known. The obtained results of the performed studies allow obtaining analytical dependencies and calculating the most expedient design parameters of the die heads, as well as choosing the optimal technological parameters of the process of products manufacture, including those with complex shapes originating from both existing and new polymer compositions.

122-127

Authors: I.V. Trembus, Ju.S. Trophimchuk, V.V. Galysh

Wood fibers are the most common material for the production of paper and cardboard. However, forest resources are decreased rapidly nowadays due to their use in cellulose and papermaking industry and in some competing industries, such as building and furniture productions. It is necessary to propose new resources of raw materials and new environmentally friendly methods for obtaining pulp to produce different paper products. In this study, the methods for the cooking of sunflower stalks were developed using peracids, in particular peracetic and performic acids. The chemical and physical properties of pulps were investigated. High-quality pulps were obtained with a yield in the range from 46 to 94% and with the content of residual lignin from 1.2 to 9.6%. The effects of temperature and duration of the delignification process on the quality indices of the obtained pulp were investigated. The lignin-carbohydrate diagram of delignification of sunflower stalks by different methods was developed. The regression equations for the process of peracetic cooking of sunflower stalks were derived. The optimal parameters of the oxidative-organosolv delignification of sunflower stalks were obtained with the application of Harrington's desirability function.