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

5-11

Authors: V.G. Vereschak, A.S. Baskevich, E.M. Brodnikoskyi

We investigated the process of stabilizing high-temperature tetragonal and cube modifications of zirconia by yttrium (III) with the use of heterometalic methanesulfonate complexes of zirconium (IV) and yttrium (III). Heterometalic methanesulfonate complex of zirconium (IV) Zr(1-х)YхO(CH3SO3)24H2O (x=0.01–0.1) was prepared by the method of the concurrent crystallization of ZrO(CH3SO3)24H2O and Y(CH3SO3)34H2O aqueous solutions. The fabricated complex salts were exposed to a vacuum drying and calcining at the temperatures in the range of 150 to 750С. According to the data of physicochemical analysis, powder-like diffractometry and differential scanning calorimetry, the thermolysis of the complex compounds of Zr(1-х)YхO(CH3SO3)24H2O occurs via a complicated chemical mechanism and ends at the temperature of 540–550С with the formation of nanocrystalline zirconia powders with tetragonal or cube structures; the sizes of primary nanoparticles are ca. 20–30 nm, the sizes of aggregates are equal to 100–200 nm and the specific surface is 32 m3 g-1. The formation ether tetragonal or cube structure is determined by the amount of yttrium (III) that is introduced into the composition of initial Zr(1-х)YхO(CH3SO3)24H2O complex.

23-28

Authors: T.A. Dontsova, G.V. Krimets, O.V. Melnichuk

It is known that the method of synthesis directly affects the surface chemistry and the structural and adsorption properties of metal oxides. Thus, the purpose of the work was to synthesize nanostructured SnO2 powders by sol-gel and solvothermal methods in different media and compare their structural-adsorption properties. The main task was to investigate the structural and adsorption properties of obtained powders of tin (IV) oxide by X-ray, IR spectroscopy and low-temperature adsorption-desorption of nitrogen. As a result, it was established that using the sol-gel method yields mesoporous powders of tin (IV) oxide and the solvothermal synthesis allows obtaining mesoporous, microporous and macroporous powders depending on the medium of synthesis. It was shown that the powders of tin (IV) oxide prepared by the solvothermal synthesis are characterized by smaller crystallite sizes, higher specific surfaces and more diverse texture characteristics than the powders of tin (IV) oxide fabricated by the sol-gel method. The differences in the IR spectra of powders obtained by these two methods were revealed.

34-41

Authors: E.S. Ivantsova, S.V. Radio, G.M. Rozantsev, E.N. Shved

The results of mathematical modeling of chemical equilibrium in solutions containing orthotungstate-anion WO42– and cation Zn2+ (С(WO42–)=10–2 mol/L, С(Zn):C(W)=1:6 and ionic strength I=0.1) showed the presence of the following anions: hexatungstate-anions [W6O20(OH)2]6– in the acidity range Z=(H+)/(WO42–)=0.00–1.20; paratungstate B–anions [W12O40(OH)2]10– if Z=1.17; and its two protonated forms H[W12O40(OH)2]9–, H2[W12O40(OH)2]8– at Z=1.25 and Z=1.13, respectively, which are formed from hexa-anions. A model with a low criterion function value CF=32.6 and a global adequacy criterion 2=10.03<<2f,=0.05=63.99 was accepted as adequate to the experiment results. There are no heteropolytungstate–zincates of any compositions, including the Anderson–Evans structural type, in the acidity range of Z1.00. At an increased acidity (Z>1.30), the formation of metatungstate anions is observed, principally in the monoprotonated form H[W12O38(OH)2]6–. The synthesis conditions were determined and aquapolytungstates salts of d-metals were synthesized that contain cations with a maximum filling of d-orbitals and (n–1)d8–10ns0 electronic configuration. In the acidity range Z=0.80–1.00, two-charged cations of these metals form either Anderson-Evans hexatungsten metallates Zn2[Ni(OH)6W6O18]20H2O (Z=1.00; (Ni):(W)=1:6), where zinc is a counterion, or mixed paratungstate B–metal hydroxide [Me5W12O40(OH)2][Me(OH)2]mH2O (Z=0.80–1.00; (Me):(W)=1:6), where Ме=Co, Cu, Zn or Cd. The compositions of the obtained salts were confirmed by the methods of chemical analysis and vibrational spectroscopy. The identification of anion in compounds was performed using IR bands, which are characteristic in terms of their intensity and position. It has been found that the value Z=1.07 is the boundary acidity which allows obtaining mixed salts. New methods of fabrication of salts with paratungstate B–anions were described, which can be used for the synthesis of compounds with d-metals cations.

49-55

Authors: E.E. Martsinko, E.A. Chebanenko, O.V. Pirozhok, I.I. Seifullina, V.V. Dyakonenko, S.V. Shishkina

The introduction of 1,10-phenantroline into the structures of hexaaquacations of cobalt(II) and manganese(II) of different-metal bis(citrato)germanates(IV) results in the formation of complexes [М(H2O)2(phen)2]2[Ge(Cit)2]•nH2O (where M=Co or Mn, Cit4 is citric anion, and phen is 1,10-phenantroline) that were characterized by means of elemental analysis, IR-spectroscopy and X-ray structure analysis. According to the results of X-ray structure analysis, the synthesized substances are cation-anionic coordination compounds which contain bis(citrato)germanate(IV) anion [Ge(Cit)2]4- and complex cations [Co/Mn(H2O)2(phen)2]2+ in their composition. As compared with bis(citrato)germanates(IV) with the hexaaquacations of 3d-metals, the deprotonation of the third carboxylic group in citric acid occurs and this leads to the changes in the charge of the anion and in the molar ratio Co/Mn:Ge in the compounds. The coordination polyhedron of germanium atom does not change; it is a distorted octahedron which is formed from six oxygen atoms of three types of two thridentate chelating citric ligands. Two of six water molecules in the cation, which are coordinated to d-metal, are not displaced with 1,10-phenantroline. The frame crystalline structure of new complexes is different from the previously synthesized ones; the general feature of their structures is the formation of hydrogen bonds with the molecules of coordinated water.

63-71

Authors: O.L. Paiuk, N.Ye. Mitina, A.O. Riabtseva, V.M. Haramus, L.V. Dolynska, Z.Ya. Nadashkevych, A.S. Zaichenko

The synthesis of comb-like homo- and copolymers with terminal peroxide fragment was investigated by polymerization of polyethylene glycol (PEG)-containing macromeres in the presence of functional peroxide-containing chain transfer agent. The dependence of kinetic and material polymeric chains lengths on chain transfer agent concentration was stated as a result of its weakly inhibitory effect. The copolymerization rate constants of PEG-methacrylate (PEGMA) with dimethyl maleate (DMM) were determined. The parameters of microstructure of copolymers were calculated. It was found that DMM crumbles blocks with PEGMA units and the copolymeric microstructure approach to the alternate sequence at a certain content of DMM. The structures of copolymers were confirmed by the results of elemental and functional analyses and IR-spectroscopy. The dependences of solubility and colloidal-chemical properties of comb-like PEG-containing polymers on their microstructure were established. The explanation of the solubility dependences and colloidal-chemical properties of comb-like PEG-contained polymers via PEG side chains weak interaction was confirmed. It was shown that the fragmentation of blocks with PEG-macromere units in the consequence of PEGMA and DMM copolymerization is the reason for significant changes in colloidal-chemical properties.

77-83

Authors: О.V. Sukhova, V.А. Polonskyy, К.V. Ustinоvа

The microstructure of quasicrystal Al–Cu–Fe alloys doped with 4 to 7 at.%. of silicon or/and with 1 to 3 at.%. of boron has been investigated in this work using metallographic, X-ray fluorescent and X-ray diffraction analyses. The influence of alloying elements on the relative phase content in the structure has been determined. The highest amount of quasicrystalline icosahedric -phase is reached in the structure of the Al55Cu25Fe12Si7В1 alloy. Alloying with silicon and boron favors a decrease in the content of iron-rich phases of the alloys structure. Corrosion behavior in aqueous acidic solutions of HCl, H2SO4, HNO3 and H3PO4 (рН 1.0) was studied by means of gravimetric method. The alloys surface affected by acidic solutions was investigated using electron scanning microscopy. After 4 hours of tests, the highest mass loss per unit area for the investigated samples was observed in sulfuric and hydrochloric acid solutions, and the least mass loss per unit area was detected in nitric acid solution. The corrosion resistance in the acids also depends on the relative phase content of the alloys structure. The corrosion stability increases with increasing -, - and -phases content and decreasing iron-rich -phase content. The corrosion mainly occurs in the areas where -phase or – and –(,) interfaces are located. Al55Cu25Fe12Si7В1 alloy shows the highest corrosion resistance in the investigated acidic solutions. As compared with other alloys, the surface of the Al55Cu25Fe12Si7В1 alloy corrodes more homogeneously. This alloy can be used as corrosion-resistant coating to protect the surface of the parts of rocket-and-space complex working in aggressive acidic media.

91-98

Authors: T.V. Khokhlova, Yu.A. Chertihina, B.Zh. Mutalieva, D.E. Kudasova, K.V. Yanova, A.V. Prosyanik

The methods of the synthesis of aminofumaric acid derivatives RO2CCH=C(NH2)CO2R (R=Me, Et, Bu, Dec), MeO2CCH=C(NHR)CO2Me (R=Me, Et, Bu, Oct, Dec, C15H31, Bzl), MeO2CCH=C(NHR)CO2K (R=H, Bu, Oct, Dec), RO2CCH=C(NH2)CONH2 (R=Me, Et) and MeO2CCH=C(NH2)CONHR (R=Me, HOCH2CH2) have been developed. The monosaponification and monoammonolysis of diesters are regiospecific and occur with the participation of -ester group. This is due to low electrophilicity of the -ester group because of its effective conjugation with amino group, which is confirmed by the computational data for dimethyl ester of aminofumaric acid using DFT method (PBE/6-311+G(d,p) in terms of NBO. Screening tests of the growth-regulating activity of the synthesized compounds on the seeds of wheat, alfalfa, beet and buckwheat showed that dimethyl ester of aminofumaric acid and its monoamides at the concentration of 10–4% are the most effective stimulators of root system development. The aminofumaric acid derivatives in high concentrations are retardants. With an increase in the length of the alkyl substituents at the nitrogen and in the ester groups, stimulating properties diminish. The potassium salts of aminofumaric acid promote the development of plant stems and, to a lesser extent, the development of root system.

107-112

Authors: S.І. Avina, О.Y. Loboyko, N.B. Маrkova, O.L. Sincheskul, I.V. Bahrova

The paper deals with the characterization of platinum-based tailings derived from a recovery boiler of the production of nitric acid. The composition of the tailings was determined and the calcination process was investigated in order to improve the extraction of platinum group metals (PGM) into concentrate. According to the results of the research, the size of the majority (81.6%) of particles of the tailings is less than 0.1 mm. The results of X-ray diffraction and laser mass-spectral analyses indicate that the tailings contain 7.82 wt.% of platinum, 1.56 wt.% of palladium and 0.09 wt.% of rhodium. It also contains carbon and ferromagnetic iron. It is shown that magnetic separation used as a preparatory stage allows extracting about 20 wt.% of ferromagnetic iron from platinum-based tailings of nitric acid production. The influence of various technological parameters on calcination of PGM tailings from recovery boiler was investigated in the temperature range of 1023 to 1173 K. The largest mass loss of the tailings is up to 9 wt.% at 1123 K during 60 min of calcination. X-ray structural analysis of calcinated samples of PMG tailings from recovery boiler of nitric acid production revealed that palladium oxide decomposes and carbon is burned out in the course of calcination. The mass loss of carbon is 1.34 wt.% during 60 min of the heat treatment. It was found out that calcination leads to cracking of PGM which improves extracting process of platinum-based tailings of nitric acid production.

120-124

Authors: А.V. Zaichuk, А.А. Amelina

The paper establishes the conditions of preparation and patterns of change of the ceramic pigment color indices in the system CaO–MgO–Al2O3–SiO2–СоО–Cr2O3. Granulated blast-furnace slag was used as a basic component, it is characterized by high content of oxides of calcium, magnesium, aluminium, and silicon(IV) oxide (in total, about 97 wt.%) and chiefly represented by an active vitreous phase. It is shown that the replacement of the part of chromium(III) oxide in the composition of experimental pigments by cobalt(II) oxide contributes to widening their color range. Low-temperature (with a firing temperature of 1200С) pigments of dark-green (=501–502 nm) and turquoise (=493–495 nm) coloring were synthesized. The main phases which determine the color of such pigments are calcium-chromium garnet (uvarovite) formed via direct involvement of minerals of the blast-furnace slag and spinel (cobalt chromite). The developed pigments are characterized by high chemical stability (water resistance of 99.62–99.64%; 1 N HCl acid resistance of 92.33–92.38%; and 1 N NaOH alkali resistance of 91.34–91.53%). Their use ensures production of high-quality glass coatings in blue-green color range (=492–540 nm).

133-138

Authors: V.I. Sitar, V.М. Anisimov, N.B. Mitina, S.М. Garmash

In this work, we investigated the effect of microorganism in vermicompost on the biodegradation of linear block copolyurethanes which contain starch. The surface structure of composite specimens with different polyurethane and starch ratios was studied. Optical studies of the surface of polyurethane samples at various ratios of polyurethane/starch showed that the surface relief of the samples significantly changes with increasing the starch content. That indicates the processes of biodegradation of polyurethane occur and its physical properties change. The results of research showed that the number of microorganisms' colony formations on the surface of composite samples increases when the starch content increases. These microorganisms affect both starch and matrix polyurethane. The optimal ratio of polyurethane/starch (50:50) has been established at which the mass of samples decreased by 20%. This indicates the initiation of biodegradation by starch, which is a nutrient for the microorganisms. An increase in the content of starch is accompanied by a decrease in the density of the investigated materials. This is due to a decrease in the molecular weight of the polymer resulting from the destructive action of microorganisms. Increasing the exposure of samples of polyurethane and starch content contributes to a decrease in the viscosity of solutions of polyurethane compositions by 27%. The products of biodegradation of polyurethane after their assimilation by microorganisms and microbes enrich the soil with useful elements and serve as additional fertilizers.

148-158

Authors: O.B. Tselishchev, M.H. Loriya, S.V. Boichenko, P.Y. Yelisieiev, Matvieieva I.V.

The subject of research was the process of direct cavitation conversion of gasoline hydrocarbons into the components of motor fuels in the mixture with aqueous solution of hydrogen peroxide. The effect of process parameters on the degree of conversion of alkanes into methanol has been determined. The analysis of technological process of direct cavitation conversion of gasoline hydrocarbons into motor fuel components as a control object was performed. The output, regulating and perturbation parameters of the process have been established. The process of direct cavitation conversion of hydrocarbons into the components of motor fuels, for example into methanol and toluene, was investigated using aqueous solution of hydrogen peroxide. The developed technology allows increasing the octane number of gasoline. It was established that the processes of paraffin isomerization and toluene formation occur in the course of cavitation treatment of gasoline without hydrogen peroxide which allows increasing the octane number of gasoline by ~4 units. However, the octane number increases by ~10–12 units when the cavitation treatment of gasoline is carried out with the solution of hydrogen peroxide. The optimal parameters of the cavitation treatment of gasoline were determined which ensure an increase in the octane number. The parameters were determined, beyond which methanol and toluene are not discovered in the products of the cavitation treatment. The reason is the lack of the conditions for the cavitation and, consequently, for the formation of proper radicals. The process installation of the cavitation treatment of hydrocarbons into methanol is characterized by relatively high efficiency, a small number of devices, and low energy, material and metal consumption; the process parameters are completely accessible in industry.