Proc. of the Natl. Academy of Sciences of Belarus, Ser. Chemical Sci., 2007, No.1
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Proc. of the Natl. Academy of Sciences of Belarus, Ser. Chemical Sci., 2007, No.1
| Proceedings of the National Academy of Sciences of Belarus
(Vestsi Natsiyanalnai Akademii Navuk Belarusi)
SERIES OF CHEMICAL SCIENCESPublished by The Belaruskaya Navuka Publishing House, Minsk, Republic of Belarus |
Number 1, 2007
CONTENTS
INORGANIC CHEMISTRY
Shauchenka S. V., Bashkirau L. A., Petrov G. S.
Thermogravimetric investigations of high temperature phase transitions in LaCoO3 and solid solutions La1-xNdx ÑîÎ3, La1-xGdx ÑîÎ3. pp. 5--9
Summary: Analysis of DTA, TG-curves (obtained in air) of LaCoO3 and solid solutions La1-xNdx ÑîÎ3, La1-xGdx ÑîÎ3 having structure of rhombohedrally and orthorhombically distorted perovskite as well as cobalt oxide Co3O4 was conducted. It is found that all investigated cobaltites have small endothermic effects at 1013 and 1208 K accompanied by mass loss (less than 0.2%), which corresponds to the temperature of end of overstoichiometric oxygen evolution by Co3O4 and its thermal decomposition with formation of CoO and O2. An assumption is made that the endothermic effect at 1208 K is due to thermal decomposition of clusters having composition close to that of Co3O4 and forming at 648--1210 K as a result of electron exchange between three-valent cobalt ions. It is not excluded that observed small endothermic effects and mass loss (less than 0.5% mas.) at 1013 and 1208 K are caused by the presence of Co3O4 in the cobaltite samples investigated.
Ivanova Y. A., Ivanou V. N., Ivanou D. K, Streltsov E. A.
Tellurium electrodeposition onto n-Si and photoelect-rochemical properties of n-Si/Te heterostructures. pp. 10--14
Summary: The process of cathodic deposition of Te from 0.05 mM TeO2 + 0.1 M HNO3 aqueous solutions onto n-type Si(100) wafers was studied. Analysis of current-time transients shows that Te deposition occurs via progressive 3D nucleation. Being electrodeposited onto n-Si wafers, tellurium particles do not undergo anodic stripping because Schottky barrier forms on n-Si/Te interface. The barrier is responsible for photo-generated electron-hole pairs separation and their further photoelectrochemical reactions. Tellurium particles serve as effective hole acceptors inhibiting in such a way n-Si substrate oxidation. The cathodic deposition of Te and its photoelectrochemical anodic stripping occur with nearly 100% yield.
COLLOID CHEMISTRY
Komarov V. S., Leonenko L. L, Rat'ko A. I.
Synthesis of carbon adsorbents on the basis of cellulose modified with saccharose. pp. 15--18
Summary: Modification of cellulose-containing materials with saccharose followed by active carbon preparation has been studied. It was found that sorption capacity, porosity and specific surface of the formed carbons increase with increasing saccharose contents. The influence of modifying solution temperature on porosity of the carbon obtained is discussed.
Komarov V. S., Leonenko L. L, Rat'ko A. I.
Synthesis of active carbons in the presence of inorganic templates -metal hydroxides. pp. 19--22
Summary: A dependence of structural parameters of prepared carbons on pH values of salt solutions used for cellulose modification has been found. Acidic solutions of aluminum, zinc, manganese salts inhibiting the development of carbon sorption volume bring a smaller contribution to the sample structure formed. In contrast, in the case when salt solution of magnesium salt was used as an impregnating agent, the samples having the greatest values of sorption volume are formed.
Stotskaya O. A., Poddenezhny E. N., Boiko A. A., Bogatyrov V. M., Borysenko N. V.
Rheology of colloidal systems on the basis of modified fumed silica. pp. 23--27
Summary: The rheological behavior of composite colloidal systems containing aerosil modified with chromium, vanadium and phosphorus compounds has been studied. The influence of silica particles surface modification on rheological behavior of composite colloidal systems formed on the basis of TEOS hydrolysate and fumed silica has been shown.
PHYSICAL CHEMISTRY
Azarko V. A., Agabekov V. E., Kalechyts G. V., Olkhovik V. K, Shirokii O. V.
Photochemical and spectral properties of thermal vacuum deposited films of 3-cynnamoyl-4-hydroxyquinol-2-on derivatives. pp. 28--31
Summary: Kinetics of photostimulated transformation of 3-cynnamoy1-4-hydroxyquinol-2-one derivatives in thin film state have been studied by UV and IR spectroscopy. It has been shown that photobleaching of the compounds in vacuum deposited films follows a first-order reaction equation. The estimated values of reaction rate constants vary in the range of (2.4 -- 4.7) • 10-4 s-1 and correlate with the values of induction factors (s*) of para-substitutes H, N(CH3)2, OCH3, C(O)OCH3 and Cl in the cynnamoyl fragment.
Toropova N. L, Davydov D. Yu., Toropova V. V.
State of Th(IV) in ethylenediaminetetraacetic acid solutions. pp. 32--35
Summary: The influence of EDTA anions on polynuclear forms of Th(IV) in solution at its fixed concentration and various pH has been studied. It has been found that the presence of EDTA anions results in decay of polynuclear hydroxocomplexes of Th(IV) in solution.
Bekish Y. N., Haevskaya T. V., Ivashkevich L. S., Tsybulskaya L. S.
The influence of boranes and aminobo-ranes on composition and structure of electroplated cobalt films. pp. 36--40
Summary: The influence of nature and concentration of various boron-containing compounds on electrodepositing characteristics, chemical and phase composition and structure of cobalt-boron films was studied.
Shachenkova L. N., Potapova L. L., Cherches B. Kh., Yermolenko Ye. N., Yegiazarov Yu. G.
Kinetic regularities of methyl-tert-amyl ether synthesis in the presence of fibrous and granular sulfonic cation exchangers. pp. 41--45
Summary: Kinetic regularities of MTAE synthesis over fibrous gel-structured sulfonic cation exchanger FIBAN K-1 and granular macroporous sulfonic cation exchanger DOWEX msm 31 have been determined and values of the kinetic constants have been defined. The reaction rate over FIBAN K-l has been shown to exceed the rate for the granular catalyst at reaction temperature >75 °C (applicable in industry).
ORGANIC CHEMISTRY
Khripach V. A., Zhabinskii V. N., Ivanova G. V., Khripach N. B.
Sharpies asymmetric hydroxylation of D22-steroids of the stigmastane series. pp. 46--51
Summary: Sharpies asymmetric hydroxylation of stigmastane D22-derivative (I) has been studied in details to elucidate the influence of catalyst type, reaction time, and amounts of some other ingredients on the ratio of 22R,23R- and 22S,23S-diols (II) and (III) as well as the overoxidation product - 6,22,23-triketone (IV). The choice of catalyst has been found to be of particular importance for preparation of natural 22R,23R-diols (II). The obtained oxidation products (II-IV) proved to be good model compounds for NMR studies of 22,23-functionalized stigmastane steroids.
Dikusar E. A., Kozlov N. G., Potkin V. L, Yuvchenko A. P.
Amine and phosphyne salts of aromatic azomethyne carboxylic acids - derivatives of vanillin and vanillal. pp. 52--53
Summary: A method of synthesis of amine and phosphyne salts of aromatic azomethyne carboxylic acids, derivatives of vanillin and vanillal, has been described.
BIOORGANIC CHEMISTRY
Survilo L. I., Nezhinets E. A., Kuprina N. S., Scherban A. L, Matveyentsev V. D., Kiseleva E. P., Pryadko A. G., Sviridov O. V.
Biochemical characteristics and analytical parameters of an enzyme immunoassay system for the determination of txyroxin in human serum. pp. 54--61
Summary: A construction has been developed and components have been obtained of a solid phase enzyme immunoassay system for thyroxine determination intended for use in thyroid diagnostics. The system enables to perform the whole analysis during a working day and to obtain analytical data in a working range of 25--400 nmol/l. The assay results correspond to clinical characteristics of the disease and have a variation coefficient less than 10%, and both the linearity and recovery in a range of 80--120%, while a detection limit does not exceed 12.5 nmol/l.
Potapovich M. V., Eryomin A. N., Rubinov D. Â., Metelitza D. I.
Activity of glucose oxidase Aspergillus niger and pair glucose oxidase -- peroxidase in reversed micelles of Aerosol ÎÒ in heptane in the presence of tralkoxydime. pp. 62--68
Summary: The catalytic activity of individual glucose oxidase Aspergillus niger (GO) and pair GO -- horseradish peroxidase (HRP) has been determined at 25 °C in aqueous medium and reversed micelles of Aerosol OT (AOT) in heptane. The D-glucose oxidation in the AOT micelles was monitored via H2O2 consumption in the peroxidase-catalyzed oxidation of tetramethylbenzidine (TMB). The use of o-phenylenedi-amine (PDA) as a reducing substrate of HRP was purposeless since the PDA abundance inhibited the enzymatic process. The application of toluene in a micellar medium to increase tralkoxydime solubility significantly decreases the rate of D-glucose, TMB and PDA oxidation catalysed by pair GO -- HRP. Tralkoxydime decreases the toluene action on the process and shortens the induction period in the TMB product accumulation. It may be used for development of an enzymatic test-system on tralkoxydime in the reversed AOT micelles aiming for determination of millimolar concentrations of this herbicide.
GEOCHEMISTRY
Aksamentova N. V., Tolkachikova A. A., Levitsky V. I.
Geochemical peculiarities of mafite-ultramafite rocks of the Argelovschina complex of Belarus. pp. 69--73
Summary: The revealed geochemical features of mafite-ultramafite rocks of the crystalline basement of Belarus (Argelovschina complex) gave a possibility to define their probable genetic origin and to determine geochemical specialty of the rocks in nickel, chromium and cobalt.
Ryabova L. N., Veremchuk S. N.
About areal distribution of metals in covering deposits of the Belarusian part of the Dnieper river basin. pp. 74--80
Summary: It was found that in deposits of the Dnieper river basin from north to south, the pH and base saturation values decrease and the leaching degree increases. Deposits of various parts of the basin are described geochemically. Northern sediments are characterized by the maximum concentrations of Ca, K, Pb, Mn and Cu, those from the central part -- by the highest content of sesquioxides, southern sediments -- by reduced concentrations of all macroelements and trace elements and a high Cr concentration.
CHEMISTRY OF HIGH-MOLECULAR WEIGHT COMPOUNDS
Yermalinskaya T. M., Fen'ko L. A., Bil'dyukevich A. B.
Phase separation in three-component systems F-42-DMF-nonsolvent and its influence on filtration characteristics of resulting membranes. pp. 81--86
Summary: The influence of non-solvent additives on properties of F-42 solutions and filtration characteristics of resulting films has been studied. Electronic microscopic measurements of the membrane surfaces have been made.
TECHNICAL CHEMISTRY AND CHEMICAL TECHNOLOGY
Shewtsuk W. W., Markin A. D., Shlomina L. E, Dikhtievskaya L. V.
Collective properties of polyamide-polyamine-epychlorhydrine resin in slime flotation of potassium ore. pp. 87--90
Summary: Possible application of polyamide-polyamine-epychlorhydrine resin as a collector of clay-carbonate admixture under slime flotation of potassium ore has been shown.
Kuzmenkov M. I., Bogdanovich I. A.
Preparation of biocompatible stomatological cement. pp. 91--94
Summary: A liquid phase preparation method of a bioactive additive, hydroxyapatite, has been developed. It is intended to introduce into stomatological cement compositions used to fill in the root channels to increase biocompatibility with tooth texture. It has been established that such technological parameters as duration of precipitate exposure to uterine solution and the temperature of hydroxylapatite thermoprocessing influence in the highest degree on bioactive admixture properties. The properties of developed stomatological cement are developed and found that the material corresponds to all requirements of technical standards.
Kozlov N. G., Karpunin V. I.
Optimization of wood alkaline brewing process in the presence of copper (II) sulfate. pp. 95--100
Summary: The wood alkaline brewing process in CuSO4 solutions has been optimized with a mathematic modulation method. The optimal conditions of fiber semiproduct preparation from various types of wood have been found.
Lamotkin S. A., Shpak S. I., Lamotkin A. I., Skakovski E. D.
Dependence of chemical composition of pine essential oil on degree of aerotechnogenic pollution of coniferous woods. pp. 101--107
Summary: The contents of toxic and radioactive elements in the needles of pines growing in various regions of Belarus has been investigated. Composition of the essential oils isolated from selected samples of the needles has been analyzed. The dependence of chemical composition of pine essential oils on the degree of territory contamination by toxic elements and radionuclides is demonstrated.
REVIEWS
Sokolov Yu. A.
Application of quantum-chemical methods in search of quantitative structure-activity relationships. pp. 108--121
Summary: The current state of research on the problem of quantum-chemical methods application in search of quantitative structure-activity relationships (QSAR) has been analyzed. Principal quantum chemical descriptors and trends of quantum chemical methods application to search for QSAR and to predict biologically active compounds are described. The publications appearing in the last decade and dedicated to some concrete results of QSAR researches with application of quantum chemical methods are adduced.
SCIENTISTS OF BELARUS
Lesnikovich A.I., Krutko N.P., Bil'dyukevich A. B. et al.
Nikolai Artemyevich Maier (To the 75th Anniversary). pp. 122--123
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