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Fine Chemical Technologies

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Vol 8, No 6 (2013)
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9-16 63
Abstract
The dependence of zeolite type in a composite catalyst, namely structural features, presence of alkali metal cation and total acidity, on the composition of Fischer-Tropsch product has been shown in the article. Highly dispersed skeleton cobalt (Raney cobalt) was used as active metal. It was found that the presence of zeolite in Hform in the composition of the catalyst results in the formation of a larger number of unsaturated and branched hydrocarbons. The cobalt composite catalyst based on HBeta zeolite is more active and more productive in the synthesis of C<sup>5+</sup> hydrocarbons from CO and H<sub>2</sub> than the catalyst based on KA zeolite. Assumptions of the role of zeolite acid sites in secondary transformations of hydrocarbons produced from CO and H<sub>2</sub> on skeleton cobalt were done.
17-19 55
Abstract
The article presents the results of research on the preparation of carbon nanofibers from an acetylene-containing gas formed as a result of the disposal of liquid industrial organic waste in the electrocracking process. It is shown that the electrocracking gas can be used for the production of carbon nanofibers. By changing the conditions of the synthesis and modifying the original catalyst it is possible to influence the increase of the output of carbon nanofibers.
20-26 55
Abstract
The process of ethanol dehydrogenation to acetaldehyde upon different copper supported on carbon catalysts has been studied. Different carbon materials – activated carbon Norit, carbon-carbon composite sibunit and activated carbon fibers (ACF) – were used as a support for the catalyst. The BET surface area as well as the porous structure of the materials were determined with the use of N2 adsorption-desorption technique. The catalysts prepared by wetness impregnation contained 5% of Cu. The effect of the carrier texture on the distribution of active metal has been shown using scanning electron microscopy. Copper deposited on ACF was well distributed in comparison with the other supports studied and had an average particle size of 20 nm. This led to higher activity of the 5% Cu/ACF catalyst. Besides, it appeared more selective in the process of dehydrogenation.
27-36 55
Abstract
There are many different methods of petrochemical raw materials activation. This article discusses hydrocarbons mechanoactivation that helps to increase the yield of the key products. This effect shows itself most clearly in the n-alkanes distribution. The main purpose of this study is to attempt to learn whether the energy of a single pulse of cavitation occurring in a disintegrator DA-1 is enough for the destructive transformation of n-alkanes with the number of carbon atoms in the molecule less than 15 and for the formation of compounds with low molecular weights. It was shown that the total decrease in the concentration of reactants (monomethyltridecane, n-tridecane and n-pentadecane) is completely compensated by the higher content of n-tetradecane in the mixtures. The content of iso-alkanes, n-tridecane and n-pentadecane decreased. Other compounds did not appear in the mixtures after the impact of a single pulse of cavitation. It was shown that the energy of a single pulse of hydrodynamic cavitation released in DA-1 is insufficient for the large-scale break of the bonds between the secondary carbon atoms in the chains of C<sub>13</sub>–C<sub>15</sub> alkanes (mostly n-tetradecane, the content of which in the mixture was greater than 97%) and for the diffusion of radicals from the “cage” with the formation of compounds with low molecular weights. A similar effect can be expected especially in respect of n-alkanes having a fewer number of carbon atoms. A possible mechanism of the reversible isomerization reaction in the studied system is discussed in this article.
37-41 49
Abstract
The initiating action of hydrogen peroxide on the catalytical transformation of ethanol into aromatic hydrocarbons was studied. It was shown that the total yield of aromatic hydrocarbons increases with increasing time of contact and temperature, when rapid coking of the surface of the zeolite-containing catalyst HZSM-5 occurs in the absence of hydrogen. The modifying action of hydrogen peroxide by the catalyst surface hydroxylation and initiation of the rate-limiting step of ethylene oligomerization with the participation of peroxide radicals HO2 • was hypothesized.

THEORETICAL BASES OF CHEMICAL TECHNOLOGY

47-53 56
Abstract
In this work we used results of p,Vm,T,x-measurements of water – alcohol mixtures (methanol, ethanol and 1-propanol) with x = 0.2, 0.5, 0.8 in the range of temperatures 613.15–653.15 К and pressures 20–50 MPa for calculation of partial molar volumes. The dependence of molar volume on concentration Vm = f(p,x)T is described by a polynomial equation with relative deviation 0.5%. A characteristic feature for all of three studied mixtures is that an insignificant growth of the partial molar volumes of water and a decrease of the partial molar volumes of the alcohols take place with increasing alcohol concentration. Water – hydrocarbon mixtures in the critical state have a similar character of the dependence of partial molar volume on concentration.
42-46 46
Abstract
By the method of isothermal pressure increasing in a closed system starting temperatures (TS) of thermal decomposition of aliphatic alcohols (methanol, ethanol, 1-propanol and 1-butanol) in their water solutions depending on composition are obtained. Values of TS depending on composition (x) and number of carbon atom (C) are described by the polynomial equation: 544.258 2 28.826 10 3 2 65.617 6.378 10 2 ( , ) 23.622 + − + ⋅ − T x N = x − x + ⋅ N N . It is shown that the rate of alcohol decomposition depends on temperature and concentration (in water-alcohol solution). To estimate rate of thermal decomposition of alcohols we used change of pressure of system in a unit of time at constant temperature and volume (closed system). Reaction rate constant was calculated by formula: dτ dp p k = 1 ⋅ , where k – reaction rate constant; p – pressure; τ – time; dp/dτ – rate of reaction. Values of kinetic and activation parameters of alcohol decomposition in the range of temperatures 583.15–663.15 К are estimated.
54-58 46
Abstract
The values of minimum reflux ratio for distillation of zeotropic ternary mixtures were calculated in case of direct and indirect splits. A comparative analysis of these regimes was carried out using the vapor flow criterion. Depending on the feed composition the areas of more favorable process organization were determined in a concentration simplex. It was concluded that when calculating of minimum reflux it is necessary to consider that the relative volatilities of components are not constant along the apparatus even for ideal mixtures.
59-62 43
Abstract
A method of surface tension calculation used by Sugden is based on the difference in the densities of a liquid and its vapor. A similar result was obtained by Bachynskyi. To expand the field of application of the formula for polar liquids Steele polarity factor was introduced. The experimental data have an error of up to 3%. The generalized processing of the experimental data by the surface tension of hydrocarbons enables to obtain a calculation formula for determining the temperature dependence of the modified surface tension of hydrocarbons. Parameters (temperature and surface tension) corresponding to minimum of free energy for the liquid – vapor phase transition were used as modification scales when constructing the generalized dependencies. The developed method was used to summarize the experimental data by the surface tension of gas condensates of different areas.

CHEMISTRY AND TECHNOLOGY OF ORGANIC SUBSTANCES

63-67 68
Abstract
The results of a research on the influence of activation of carbon fibers in CO2 current on the change in their specific adsorptive surface and porous structure are presented. The fibers under study were produced from viscose and polyacrylonitrile. It is shown that as a result of activation the specific surface of carbon fibers can be increased from 0.3 to 1900 m2 /g, and the volume of porous space, from 0.1 to 400 cm3 /g. It is established that the nature of the initial fiber has an essential influence on the extent of change in specific surface and porous structure. After activation fibers based on viscose have significantly greater values of specific surface and a bigger fraction of micropores in their structure than fibers based on polyacrylonitrile.
68-72 47
Abstract
Serological tests based on an agglutination reaction are commonly applied in clinical laboratories for the diagnosis of various infectious diseases. There is a wide selection of microsphere-based diagnostic agglutination tests (yes/no results) and assays (quantitative results) worldwide. However, due to rapidity and no need for special equipment passive hemagglutination tests are still the most frequently used routine tests in Russia. These hemagglutination tests are run in 96-well microplates with V-shaped bottoms. The substitution of red blood cells for polymer microspheres in such semi-quantitative tests is difficult due to a number of reasons. When choosing the appropriate microspheres for rapid passive latex agglutination tests, it is important to consider such variables as their size (and size distribution), density and colloidal stability. In our study we showed the development of rapid (1-3 hours) passive latex agglutination tests based on the knowledge of sedimentation stability of polymer suspensions. We studied sedimentation rates of sheep and chicken erythrocytes used in passive hemagglutination tests and identified the required intervals of sedimentation rate for polymer microspheres. Based on these dates a theoretical model of polymer microsphere motion within a V-shaped well was proposed, which revealed that the formation of a lattice in the passive latex agglutination reaction takes place not in the volume of the well, but on the surface of the well bottom.
73-77 63
Abstract
The kinetics of oxidative polymerization of 2-methylaniline in hydrochloric acid aqueous solution in the presence of ammonium peroxydisulfate as the oxidant was studied. The presence of autocatalysis was demonstrated, and the reaction mechanism was suggested. On the basis of the mechanism a kinetic model of oxidative polymerization of 2-methylaniline was built. The model is in satisfactory agreement with the experimental results.
78-81 78
Abstract
The organic waste generated in the caprolactam production contains a complex mixture of mono- and dicarboxylic acids. It is shown that using two-step oxidation by aqueous hydrogen peroxide allows to isolate adipic acid of high quality. In case if the yield of acids is up to 95% of the nominal value the production of chemicals with high added value can be up to 10 kilotons per year. Retrieving adipic acid from industrial waste will help to solve both economic and environmental issues.

CHEMISTRY AND TECHNOLOGY OF INORGANIC MATERIALS

82-87 52
Abstract
In spite of the fact that solid solution CdxHg1-xTe is the most sensitive and effective semiconductor material for matrix photodetectors, weak internuclear connection Hg–Cd and high energy диссоциации molecules Tе2 result in formation CdxHg1-xTe epitaxial layers defects in process MBE epitaxial growth of layers which negatively influence on matrix detector device work. The defects and structural imperfections of epitaxial layers essentially worsens uniformity of distribution of photosensitivity of elements and lowers photo-electric parameters of matrix photodetectors. Therefore the problem of CdxHg1-xTe epitaxial layers defectiveness became the basic at manufacturing of matrix photodetectors, in particular, with small (15-20 microns) step of photosensitive elements. Voltage-current characteristics matrix photosensitive elements were investigated. The analysis of the basic components the dark current and the diagram of photo-electric parameters matrix photodetectors were carried out depending on presence structural and large defects in area p-n transition. Influence of defects on the dark current of matrix detector devices was described. It was established correlations between photo-electric defects matrix detector devices and defects heteroepitaxial layers of the solid solutions CdxHg1-xTe on the basis of which photosensitive elements for matrix devices are created.
88-94 44
Abstract
Data on a systematic research of the extraction of nitric and chloride acids from mixed nitric-chloride solutions with neutral oxygen containing compounds – triisoamylphosphate and isoamyldyalkyl (C7–C9) phosphine oxide are presented. The composition of the extracted compounds is determined, the isotherms of the extraction of acids for solutions with different salt composition are obtained. It is shown that from the nitric-chloride mixed solutions of different composition, when used as extractants neutral oxygen containing compounds, in organic phase goes mainly nitric acid.

SYNTHESIS AND PROCESSING OF POLYMERS AND POLYMERIC COMPOSITES

95-98 49
Abstract
In this work the electrospinning of copolymeric polyamide-6/66 in ethanol-water solution is studied and the properties of the obtained fibrous materials are investigated. The principal possibility of obtaining fibrous materials in ethanol-water spinning solutions via electrospinning is shown. The optimal ratio of these solvents in spinning solution is determined. The investigated properties of the obtained fibrous materials include fiber diameters, fiber size distribution and packing density.
99-102 42
Abstract
The process of foaming rigid PVC composites using azodicarbonamide as foaming agent was studied. The effect of this process on the thermal degradation of the polymer and the role of azodicarbonamidat various temperatures were analyzed.
103-107 53
Abstract
The composites of high density polyethylene with carbon black were prepared by melt-blending method. The effect of processing additives on electrical properties of carbon black-filled polyethylene composites was investigated in detail. It was found that viscosity of melts and positive temperature coefficient of electrical resistivity (PTC) were improved by the incorporation of zinc stearate due to the increased distribution of CB. On the other hand, addition of organosilicon oligomers led to a decrease in viscosity and had almost no effect on PTC.
108-110 65
Abstract
The convenient synthesis of the key structure fragments of polyamide nucleic acid mimic (PANAM) monomers according to route using Mitsunobu’s reaction and subsequent thiolysis of protective o-nitrobenzenesulphonyl group is presented. The purification of target secondary amines was occurred after the thiolysis stage by an extraction at various pH, without isolation of fully protected pseudopeptide intermediate derivatives. Thus, it were obtained BocGlyΨAlaOAll, BocAlaΨGlyOMe, BocGluΨGlyOAll, BocGlyΨGlyOMe, CbzAlaΨGlyOMe, CbzGlu(Ot Bu)ΨGlyOMe. It was shown that yields of target compounds are comparable both by the employing of purification stage of intermediates and without it. The key condition of successful applying of presented method is the absence of initial “acid component” in the reaction mixture undertaken to thiolysis.
111-113 50
Abstract
Folate lipoconjugates were synthesized by induction of spacers to 1,2-di-O-tetradecyl-rac-glycerol for future condensation with folic acid. The intermediates hydrophobic compounds were obtained by treatment of 1-О-(4- nitrophenyloxycarbonyl)-2,3-di-O-tetradecyl-rac-glycerol with free diamines (1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, 1,12-diaminododecane) in the presence of triethylamine. Condensation of intermediate compounds (1 eq.) and folic acid (3 eq.) were carried out in the presence of (O-(benzotriazol-1-yl)- 1,1,3,3-tetramethyluronium tetrafluoroborate (3 eq.) and N,N-diisopropylethylamine (5 eq.) and gave targeted folate lipoconjugates. The structures and purity of the compounds synthesized were confirmed by analytic physicochemical methods.


ISSN 2410-6593 (Print)
ISSN 2686-7575 (Online)