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  • 1
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mit einer Strömungsapparatur wurde die Kinetik der katalytischen Eliminierung C2H5Cl→C2H4+HCl an MgSO4 und Al2O3 zwischen 280 und 430°C und bei Drucken zwischen 2 und 35 Torr mit Helium als Trägergas untersucht. Störungen durch Diffusion sowie die Rückreaktion wurden dabei weitgehend ausgeschaltet. Durch Variation der Verweilzeit bei konstantem Anfangsdruck kann gezeigt werden, daß die Reaktion über den ganzen Umsatz nach erster Ordnung verläuft. Die Geschwindigkeitskonstante nimmt jedoch mit steigendem Anfangsdruck ab. Vorliegen einer Adsorption vomLangmuirtyp erklärt dieses Verhalten. Die spezifische Aktivität von MgSO4 (Aktivierungsenergie 28 kcal/Mol) ist rund 1000mal höher als die von Al2O3 (Aktievierungsenergie 21 kcal/Mol), was durch den höheren Häufigkeitsfaktor von MgSO4 bedingt ist.
    Notes: Abstract The kinetics of the catalytic elimination C2H5Cl→C2H4+ +HCl over MgSO4 and Al2O3 was studied at pressures between 2 and 35 torr and in the temperature range 280° to 430° C. A flow apparatus was used with He as carrier gas. Influences of diffusion and back reaction were avoided. At a given initial pressure the reaction obeys a first order kinetic law over the whole conversion. However, the rate constant decreases with increasing initial pressure. This is interpreted with aLangmuir type adsorption. The specific activity of MgSO4 (activation energy 28 kcal/mol) is roughly 1000 times higher than that of Al2O3 (activation energy 21 kcal/mol). This is due to a higher frequency factor of MgSO4.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 102 (1971), S. 22-32 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract The dynamics of the catalysis of hydrogenation and oxidation reactions are interpreted on the basis of the principle of chemical functions. It is shown that the electron population of the catalyst must meet the following conditions: (1) to enable the exhibition of either a donor or an acceptor function, (2) to achieve hereby the reversal of the function of the reactant, and (3) to attain finally the initial electron population.
    Notes: Zusammenfassung Die Dynamik der Katalyse von Hydrierungs- und Oxidationsreaktionen wird unter Zuhilfenahme des Prinzips der chemischen Funktionsfolge1 interpretiert. Es wird gezeigt, daß die Elektronenpopulation am Katalysator so beschaffen sein muß, daß sie 1. zur Ausübung entweder einer Donor- oder einer Acceptorfunktion gegenüber einem der Reaktanten befähigt ist, 2. dadurch dem Reaktanten die Umkehr der dem Katalysator gegenüber ausgeübten Funktion aufzwingt, wodurch die Reaktion mit dem Reaktionspartner ermöglicht wird und 3. die unter 1. bezeichnete Veränderung der Elektronenpopulation die Umkehrung der dem Reaktanten gegenüber ausgeübten Funktion des Katalysators ermöglicht, der hiedurch in den Anfangszustand zurückkehrt.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Reaction kinetics and catalysis letters 21 (1982), S. 479-483 
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Добавление малых количеств меди к никелю Ренея увеличивает его активность в гидрогенизации кротонового альдегида и его селективность в гидрогенизации связи C=O. Повышенные количества приводят к повышенной селективности, но к пониженной активности. Для обьяснения этого был использован подход химической координации на катализаторе.
    Notes: Abstract Addition of small amounts of copper to Raney Ni increases its activity for hydrogenation of crotonaldehyde and its selectivity for C=O bond hydrogenation. Higher amounts lead to higher selectivity but lower activity. The coordination chemical approach to catalysis was used to explain this result.
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  • 4
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Изучалось влияние активности смешанных окислов MgO−Al2O3 на распад диацетоналкоголя. Измерения проводились в микрореакторе, который позволял проводить предварительную обработку катализатора непосредственно в реакторе. Скорость реакции была использована как характеристика прочности основных поверхностных центров. Наблюдался первый порядок реакции и у меньщении скорости реакции от MgO к Al2O3.
    Notes: Abstract The activity of MgO−Al2O3 mixed oxides in the decomposition of diacetonealcohol was studied using a micro slurry reactor, which allowed pretreatment of the catalyst in situ. The rate constant was used to characterize the strength of the basic surface sites. A reaction order of one and a decrease of the rate constant from MgO to Al2O3 was observed.
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  • 5
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Исследованы активность и селективность медно-железных катализаторов синтеза легких спиртов из моноксида углерода и водорода. Определены благоприятное соотношение меди к железу и оптимальный химический состав катализатора.
    Notes: Abstract The activity and selectivity of copper-iron catalysts for the synthesis of light alcohols from carbon monoxide and hydrogen were studied. The suitable ratio of copper to iron and optimal chemical composition of the catalyst were determined.
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  • 6
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Распределение компонентов в катализаторе HG-1, промотированном окисями редкоземельных металлов (успешно разработанный авторами) и используемом в синтезе аммония, определяли на основе электронной микропробной фотографии. Объяснено влияние примесей на активность, а также исключительно большое время жизни катализатора.
    Notes: Abstract The distribution of components in the HG-1 ammonia catalyst promoted by rare earth oxide (successfully developed by the authors) was analyzed by electron microprobe photography. The results enable us to explain the effect of additives upon the activity as well as the remarkably high lifetime of catalyst.
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  • 7
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Обнаружен кислотный характер ZnO в спекроскопических измерениях (полоса Zn−H при 1708 см−1, XPS O 1s связывающая энергия имеет значение 530/532 э.в., Люисова полоса пиридина при 1452 см−1), а также основной характер в реакциях спиртов (98% дегидрования). Это объясняется высокой чувствительностыо катализатора к условиям эксперимента.
    Notes: Abstract Acidic behavior of ZnO is observed in spectroscopic experiments (Zn−H band at 1708 cm−1, XPS O 1s binding energy 530/532 eV, pyridine Lewis band at 1452 cm−1), basic behavior in catalytic reactions of alcohols (98% dehydrogenation). This is ascribed to a high sensitivity to experimental conditions.
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 216 (1967), S. 1181-1185 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The protein sub-unit of glyceraldehyde 3-phosphate dehydrogenase consists of a single chain of 333 amino-acid residues, corresponding to a molecular weight of 36,000. Amino-acid sequence studies show that the active enzyme-NAD complex with a molecular weight of 146,000 is composed of four protein ...
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  • 9
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Vacuum 22 (1972), S. 404 
    ISSN: 0042-207X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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