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2004 year, number 6

1.
Radical Generation during Pyrolysis of n-Undecane on BaCl2 and Imperfect Magnesium Oxides

N. A. Vasilieva and R. A. Buyanov
Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Lavrentyeva 5, Novosibirsk 630090 (Russia), E-mail: Nel@catalysis.nsk.su
Pages: 641-647

Abstract >>
The kinetics of ethyl radical generation during the pyrolysis of n-undecane on barium chloride (accelerating the heterogeneous constituent of the process) and on defect-bearing magnesium oxides (accelerating the homogeneous constituent of the process) was investigated by means of freezing out in the cavity of the EPR spectrometer. It was shown that the activation energy of radical generation on barium chloride (E = 192 kJ/mol) is lower than the activation energy of thermal pyrolysis (E = 322 kJ/mol). The phenomenon of ignition of the surface is observed with the catalysts that accelerate the homogeneous constituent of the process and create the «catalysis sphere.» Below the critical temperature, in spite of the presence of catalysts, ordinary thermal pyrolysis goes on between the catalyst granules. At a higher temperature, the catalyst generates radicals with the activation energy characteristic of the radical reactions (E = 4 kJ/mol). The possibility to increase the productivity and to control the selectivity of pyrolysis of hydrocarbons by including non-conventional heterogeneous catalysts into the process is demonstrated.



2.
Solubility of Uranium Dioxide during Underground Disposal of Radioactive Wastes and Spent Nuclear Fuel

O. L. Gaskova1 and M. B. Bukaty2
1Institute of Mineralogy and Petrography, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Koptyuga 3, Novosibirsk 630090 (Russia), E-mail: gaskova@uiggm.nsc.ru
2Institute of Gas and Petroleum Geology, Tomsk Affiliation,
Siberian Branch of the Russian Academy of Sciences,
Pr. Akademicheskiy 3, Tomsk 634055 (Russia)
Pages: 649-655

Abstract >>
The problem of reliable prediction of the safety of burial of the spent nuclear fuel in the environmental components is connected with the reliability of quantitative models describing solubility/precipitation of uranium dioxide UO2(s) as the major component, depending on a number of physicochemical parameters, such as temperature, Eh-pH, salt composition and concentration of electrolyte solutions. In the present paper we report on the free Gibbs' energy of formation of this phase and the accompanying complexes in the solutions of different composition. The reported values of Gibbs' energy allow reliable model reproduction of the experimental results on solubility and the concentrations of dissolved uranium observed in nature. In addition, the reasons that may cause local non-equilibrium fluctuations of the concentrations of this element under the conditions conjugated with the radioactive decay of short- and medium-lived isotopes are discussed.



3.
Thiokol-Like Polymers Based on By-Products of Epichlorohydrin Production

Yu. K. Dmitriev1, N. A. Loktionov1, Yu. A. Sangalov2, S. G. Karchevskiy3, I. O. Maidanova3 And S. N. Lakeev3
1"Caustic» Company, Ul. Tekhnicheskaya 32, Sterlitamak 453110 (Russia), E-mail: irina-m@anrb.ru
2Institute of Petrochemistry and Catalysis, Russian Academy of Sciences,
Pr. Oktyabrya 141, Ufa 450075 (Russia)
3"Sodeystviye» Bashkir Innovation Centre, Pr. Oktyabrya 69, Ufa 450054 (Russia)
Pages: 657-662

Abstract >>
The issue of the use of mixtures of organochlorine products from epichlorohydrin production wastes to yield the commercially valuable sulphur-containing polymers, thiokols, is considered. It has been demonstrated that carrying out the reactions of mixtures of organochlorine compounds of various composition with sodium polysulphide in non-aqueous media (methanol) allows one to obtain powdered solid polymers, namely, polyorgano polysulphides, with 66-90 % yield and with high content of sulphur, up to 82 %. The analysis of possible ways of formation of polymers is performed; their physicochemical and structural properties are studied; suggestions are given concerning the ways of putting to work.



4.
Regeneration of Catalysts Based on Aqueous Solutions of Mo-V-Phosphoric Acids under Increased O2 Pressure

E. G. Zhizhina, M. V. Simonova, V. F. Odyakov and K. I. Matveev
Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Lavrentyeva 5, Novosibirsk 630090 (Russia), E-mail: zhizh@catalysis.nsk.su
Pages: 663-668

Abstract >>
Oxidation of the 0.2 M solutions of H7+mP(VIV)m(VV)4-mMo8O40 (HmHPA-4) by oxygen at temperatures from 373 to 433 K under O2 pressure up to 8 atm (810 kPa) is investigated. The maximal reaction rate is observed at 433 K. At a higher temperature, partially oxidized 0.2 M solutions of HmHPA-4 are thermally unstable. With an increase in the extent of oxidation of HmHPA-4 solutions, the apparent activation energy increases.



5.
Determination of Zinc in Whole Blood and Its Fractions by Means of Stripping Voltammetry Using Modified Thick-Film Carbon-Containing Electrodes

N. F. Zakharchuk1, O. I. Sudaeva1, S. Yu. Saraeva2, L. I. Kolyadina2 and Kh. Z. Brainina2
1Pr. Akademika Lavrentyeva 3, Novosibirsk 630090 (Russia), E-mail: nzak@che.nsk.su
2Ural State University of Economics,
Ul. 8-go Marta 62, Yekaterinburg 620219 (Russia), E-mail: baz@usue.ru
Pages: 669-680

Abstract >>
A rapid method to analyze the whole blood and its fractions for zinc content involving stripping voltammetery with the use of the modified thick-film carbon-containing electrodes is proposed. The method allows one to make the analysis free from metal mercury and its soluble salts, preliminary deproteinization of samples, and also to decrease the sample necessary for analysis to 5-50 ml. The measurable range of zinc concentration in blood and in its fractions is 100-20 000 mg/l.



6.
Development of Materials and Coatings Based on Polytetrafluoroethylene

N. V. Kornopoltsev, V. E. Rogov, E. V. Lenskaya and V. N. Kornopoltsev
Baikal Institute of Nature Management, Siberian Branch of the Russian Academy of Sciences,
Ul. Sakh'yanovoy 8, Ulan Ude 670047 (Russia), E-mail: polymer@binm.baikal.net
Pages: 681-686

Abstract >>
Results concerning the development of the new polymeric composite materials and coatings based on PTFE are presented. Experimental results obtained testify that application of such composites allows one to enhance operating performance and reliability of machines and mechanisms.



7.
Investigation of Oxidized and Modified Carbon Materials as Mercury Sorbents

L. M. Levchenko, V. N. Mitkin, I. M. Oglezneva, B. M. Shavinskiy, A. A. Galitskiy and V. E. Kerzhentseva
Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Lavrentyeva 3, Novosibirsk 630090 (Russia), E-mail: luda@che.nsk.su
Pages: 687-700

Abstract >>
An investigation of the oxidized and modified carbon materials and sorbents around them has been carried out by physicochemical methods (electron microscopy, thermoanalysis, X-ray diffraction, and IR spectroscopy). The processes of mercury sorption to the new modified carbon sorbents under static and dynamic conditions are studied with model solutions and processing media. It has been found that adsorption capacity for mercury depends on oxidation state of the carbon surface and on the properties of the introduced modifier.



8.
Realizing the Sulphur-Closed Technological Processes of Metallurgical Production

A. I. Oruzheynikov1, V. F. Borbat2 and A. G. Anshits3
1Omsk Scientific Centre, Siberian Branch of the Russian Academy of Sciences,
Ul. Neftezavodskaya 54, Omsk 644040 (Russia), E-mail: oruzh@incat.okno.ru
2Omsk State University, Pr. Mira 55a, Omsk 644040 (Russia)
3Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences,
Ul. K. Marksa 42, Krasnoyarsk 660049 (Russia), E-mail: anshits@icct.ru
Pages: 701-708

Abstract >>
The approach based on the use of sulphur dioxide from metallurgical off-gases as a reagent in the technologies of processing of the crude ore is considered, which allows, in specific cases, a sulphur closed cycle to be set up. The expedients are demonstrated, which enable one to reduce the body of sulphur ingress to processing with a feed stock, and to enhance the efficiency of sulphur productions now in operation.



9.
Carboxylic acids in the products of hydrothermal decomposition of barzassite

N. N. Rokosova1, Yu. V. Rokosov1, A. P. Kozlov1 and N. V. Bodoev2
1Institute of Coal and Coal Chemistry, Siberian Branch of the Russian Academy of Sciences,
Sovetskiy Pr. 18, Kemerovo 650099 (Russia), E-mail: han@kemnet.ru
2Baikal Institute of Nature Management, Siberian Branch of the Russian Academy of Sciences,
Ul. Sakhyanovoy 8, Ulan Ude 670047 (Russia)
Pages: 709-712

Abstract >>
The results of the experiment on hydrothermal decomposition of Barzas sapromixite aimed at obtaining carboxylic acids are reported and discussed. Normal mono- and dicarboxylic acids with 9 to 25 and with 10 to 23 carbon atoms, respectively, were identified in decomposition products. The yield of carboxylic acids from sapromixite turned out to be 2-4 times lower than for the majority of sapropelites investigated earlier.



10.
Fe-Montmorillonites in the Reaction of Organic Dyes Oxidation

S. Ts. Khankhasaeva1, L. V. Bryzgalova1, E. Ts. Dashinamzhilova1 and A. A. Ryazantsev2
1Baikal Institute of Nature Management, Siberian Branch of the Russian Academy of Sciences,
Ul. Sakh'yanovoy 8, Ulan Ude 670047 (Russia), E-mail: shan@bsc.buryatia.ru
2Siberian Transport University, Ul. D. Kovalchuk 191,
Novosibirsk 630049 (Russia), E-mail: raastu@irs.ru
Pages: 713-717

Abstract >>
Regularities in catalytic oxidation of "Acid chrome dark blue" dye in water solutions are studied under the effect of Fe-montmorillonite catalyst obtained by intercalation of iron polyhydroxocomplexes into the montmorillonite clay from Mukhortalinskoye deposit (Buryatia). An impact of the initial concentrations of reagents, temperatures, and ðÍ on the reaction rate is studied. The outcomes of organic dyes oxidation bear witness to the possibility of practical application of Fe-montmorillonite catalyst in the processes of sewage decontamination from dyes.



11.
Investigation of Thermal Transformations of the Barzas Sapromixite under Autoclave Conditions

V. I. Sharypov1, B. N. Kuznetsov1, N. G. Beregovtsova1, S. V. Baryshnikov1 and N. Yu. Vasilieva2
1Institute of Chemistry and Chemical Technology, Siberian Branch of the Russian Academy of Sciences,
Ul. K. Marksa 42, Krasnoyarsk 660049 (Russia), E-mail: sharypov@icct.ru
2Krasnoyarsk State University, Pr. Svobodny 79, Krasnoyarsk 660041 (Russia)
Pages: 719-725

Abstract >>
Thermal transformations of sapromixite from the Barzas deposit are investigated under the conditions of pyrolysis processes in an inert atmosphere, hydropyrolysis in the atmosphere of hydrogen, thermal dissolution in the residue from oil refining and catalytic hydrogenation. It is shown that sapromixite can be transformed with a high yield into liquid hydrocarbon products. The main products of this transformation is the fraction of liquid hydrocarbons with boiling point above 180 oC; its yield from sapromixite is substantially (up to 7.7 times during pyrolysis) higher than the corresponding value for brown coal. The highest degree of sapromixite conversion into liquid and gaseous products was achieved for its pyrolysis in the atmosphere of hydrogen and for hydrogenation in the presence of mechanically activated iron-ore catalyst. For hydrogenation, maximal conversion of sapromixite reaches 94-97mass % at a temperature within 400-430oC. For hydropyrolysis of sapromixite, the degree of conversion increases with an increase in the process temperature and reaches 78-80mass % at 430-460oC. Further temperature rise causes a sharp increase in the amount of gas formed and a decrease in the yield of liquid products. The application of iron-ore catalyst during hydrogenation allows one to increase the sapromixite conversion degree by 21-23% and to achieve total yield of liquid products of hydropyrolysis up to 58 mass % with rather low gas formation.



12.
Some Ecological and Economic Aspects of the Use of Sorption Heat Facilities in Russia

Yu. I. Aristov
Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Lavrentyeva 5, Novosibirsk 630090 (Russia), E-mail: aristov@catalysis.nsk.su
Pages: 727-730

Abstract >>
Ecological and economic aspects of the use of sorption heat facilities (refrigerators and thermal pumps) under the conditions existing in Russia are considered, along with their competitiveness in comparison with traditional systems. It is shown that sorption refrigerators are preferable in comparison with compression ones if waste heat (or solar energy) is used. If regeneration is carried out by burning natural gas, sorption devices can be more ecologically pure only in exclusive cases, so, in order to decrease emissions of greenhouse gases, is it reasonable to develop compression devices with high coefficient of performance (COP ³ 4). Sorption heat pumps with the coefficient of amplification COA>1 are ecologically safer and economically more efficient that gas heaters. In the case of COAabs=1.7, consumption of natural gas decreases by 41 %; for COAabs=1.5 - by 33%, which means substantial practical interest. Analysis may be useful either for the determination of the promising character of various sorption devices followed by elaboration of the corresponding technical policy or for choosing the economic parameters affecting the competitiveness of technologies, including those for separate regions of Russia.



13.
One of the Aspects of Chemical and Thermodynamic Simulation in Solving the Complex Problems of Description of the States of Water Systems

V. I. Belevantsev1, V. I. Malkova1, A. P. Ryzhikh1, B. S. Smolyakov1 and G. N. Anoshin2
1Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Lavrentyeva 3, Novosibirsk 630090 (Russia), E-mail: L311@che.nsk.su
2Trofimuk United Institute of Geology, Geophysics, and Mineralogy,
Siberian Branch of the Russian Academy of Sciences,
Pr. Akademika Koptyuga 3, Novosibirsk 630090 (Russia), E-mail: anosh@uiggm.nsc.ru
Pages: 731-741

Abstract >>
The generalized approach and methodology of formulating and solving a series of direct problems of chemical equilibrium aimed at estimating the real state of substances in aqueous solutions as subsystems of natural and technological water is presented. A minimal set of the key terms is outlined in brief (locality and partial character of equilibrium, physicochemical decomposition, initial system, system under investigation and so on); these terms are necessary to master the approach and the procedure, and also to use correctly the corresponding results in solving the complex problems connected with the description of the state of water systems. Examples of two implementations (estimation of the consumption and evolution of carbon dioxide during photosynthesis, breathing of hydrobionts, oxidative destruction of organic matter in surface water, partial analysis of the local states of mercury in the environment) illustrate the technology of applying this approach and the procedures, and also their self-descriptiveness. Specific results obtained within these examples are of independent interest.