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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 185 (1960), S. 683-683 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Uranyl ion undergoes photoreduction when exposed to sunlight in the presence of reducing agents such as alcohol or formic acid. When ammonium carbonate is added to a photochemically reduced solution of uranyl nitrate or formate, a green precipitate is obtained in a fine state, which on washing ...
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 163 (1949), S. 883-885 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] THE slow combusfcfon of hydrocarbons in general takes place bv/Tkinetic process which Semenov1 described as a ofiain reaction showing 'degenerate branching'. Ap^ording to this conception, the hydrocarbon is firac oxidized to a moderately stable intermediate, TOmch is itself oxidized to the final ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 35 (1989), S. 2153-2159 
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Im Temperaturbereich von 653–683 K wurde der Einfluß von Beimengen von Kaliumbromid (2,5% und 5%) auf die thermische Zersetzung von Kaliumbromat untersucht. Die Funktion der zersetzten Menge (α) in Abhängigkeit von der Zeit (t) weist eine anfängliche Gasentwicklung(i), eine beschleunigte(ii) und eine abklingende Stufe(iii) auf. Die Daten wurden auf der Grundlage einer Kinetik erster Ordnung mit den zwei Geschwindigkeitskonstantenk 1 undk 2 durchgeführt, wobeik 1 die Geschwindigkeitskonstante für den einleitenden, langsameren Schritt erster Ordnung ist (0,02, 0,26) undk 2 die Geschwindigkeitskonstante für den darauffolgenden schnelleren Vorgang mit Werten zwischen 0,21 und 0,98. Bei Erhöhung der Konzentration von Kaliumbromid auf 5% betrug der Bereich für den langsameren und den schnelleren Vorgang 0,01 bis 0,16 bzw. 0,10 bis 0,98. Bei gegebener Temperatur steigtk 1 mit zunehmender Kaliumbromidkonzentration an, währendk 2 für reines Kaliumbromat und seine Mischungen mit 2,5% und 5% Kaliumbromid fast identisch bleibt.
    Abstract: Резюме В температурном инте рвале 653–683 К изучено влияние добавок бром ида калия (2,5 и 5%) на термическое разло жение бромата калия. Температурные завис имости степени разло жения показали стадии перв оначального выделен ия газа, ускорения и затухани я реакции. Анализ полученных да нных проведен на осно ве реакции первого порядка с дву мя константами скоростиk 1 иk 2, где пер вая является констан той скорости начального медленного процесса первого порядка (со зн ачениями от 0,02 до 0,26), а вторая-константой ск орости последующего быстрого процесса со значениями в интерва ле 0,21–0,98. При увеличении концентр ации бромида калия до 5% интервал зна ченийk 1 иk 2 становитс я равным, соответствен но, 0,01–0,16 и 0,1–0,98. При данной температу реk 1, увеличивается с увеличением концент рации бромида калия, т огда какk 2 почти одинакова как для чистого брома та калия, так и его смесей (2,5 и 5%) с бр омидом калия.
    Notes: Abstract The effects of admixtures of potassium bromide (2.5% and 5%) on the thermal decomposition of potassium bromate were studied within the temperature range 653–683 K. The fraction decomposed(α) vs. time (t) relations revealed (i) initial gas evolution, (ii) acceleratory and (iii) decay steps. The data were analysed on the basis of the first-order law with two rate constantsk 1 andk 2,k 1 being the rate constant for the initial, slow first-order process (0.02, 0.26), andk 2 being the rate constant for the subsequent faster process, holding within the range 0.21 to 0.98. Upon increase of the concentration of added potassium bromide to 5%, the range for the slow and faster processes became 0.01 to 0.16 and 0.1 to 0.98, respectively. At a given temperature,k 1 increased with increasing bromide concentration, whereask 2 almost identical for pure potassium bromate and its mixtures (2.5% and 5% bromide).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 61 (2000), S. 879-883 
    ISSN: 1572-8943
    Keywords: anion doping ; defects ; isothermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Structural defects were introduced into the potassium bromate (PB) lattice in the form of SO2− 4 and Cl− ions in the process of crystal growth. It was assumed that these doped crystals PB(Cl−) and PB(SO2− 4) are composed of a two phase system, one being the perfect PB lattice and the other distorted regions due to induced defects. Isothermal decomposition of doped and normal PB samples was carried out gasometrically between the temperature range 653–663 K. The α-t plots reveal that the process occurs through initial gas evolution, acceleratory and decay stages. It also confirmed that doping enhances the rate of the reaction, the effect being more pronounced in the case of PB(SO2− 4). The data are found to be well fitted to the Prout-Tompkins and Avrami-Erofe'ev mechanisms.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Исследовали кинетику иодирования п-аминобензойной и о-аминобензойной кислот при различных рН и в различных растворителях. Был определён порядок реакции по концентрации иодирующего реагента и субстрата. Реакция проводилась в буфферных смесях первичных и вторичных фосфатов и определяли каталитические константы. Исследовали влияние температуры и диэлектрической постоянной растворителя. Предлагается вероятный механизм и составной закон скорости.
    Notes: Abstract Kinetics of iodination ofp-aminobenzoic acid ando-aminobenzoic acid at different pH and solvent media has been studied. The order of the reaction with respect to the iodinating agent and substrates was established. Reactions were carried out with buffer mixtures of primary and secondary phosphates and catalytic constants were evaluated. Effect of temperature and dielectric constant of solvents used were studied. Suitable mechanism and composite rate law have been suggested.
    Type of Medium: Electronic Resource
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