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  • 1985-1989  (2)
Materialart
Erscheinungszeitraum
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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 18 (1986), S. 907-917 
    ISSN: 0538-8066
    Schlagwort(e): Chemistry ; Physical Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The kinetics of the gas phase reaction between NO2 and CF2CCl2 has been investigated in the temperature range from 50 to 80°C. The reaction is homogeneous. Three products are formed: O2NCF2CCl2NO2 and equimolecular amounts of CINO and of O2NCF2C(O)Cl. The rate of consumption of the reactants is independent of the total pressure, the reaction products, and added inert gases and can be represented by a second-order reaction: \documentclass{article}\pagestyle{empty}\begin{document}$$ - \frac{{d[{\rm NO}_{\rm 2}]}}{{dt}} = - 2\frac{{d[{\rm CF}_{\rm 2} {\rm CCI}_{\rm 2}]}}{{dt}} = k[{\rm NO}_{\rm 2}][{\rm CF}_{\rm 2} {\rm CCI}_{\rm 2}] $$\end{document}However, the distribution of the products is influenced by the pressure of the present gases, which favor the formation of the dinitro-compound in a specific way. The effect of CF2CCl2 is the greatest. In the absence of added gases, the ratio of O2NCF2CCl2NO2 to that of O2NCF2C(O)Cl is proportional to (CF2CCl2 + γP products).The experimental results can be explaned by the following mechanism: P and X represent the products and the added gases: \documentclass{article}\pagestyle{empty}\begin{document}$$ - \frac{{d[{\rm NO}_{\rm 2}]}}{{dt}} = - 2\frac{{d[{\rm CF}_{\rm 2} {\rm CCI}_{\rm 2}]}}{{dt}} = k_1 [{\rm NO}_{\rm 2}][{\rm CF}_{\rm 2} {\rm CCI}_{\rm 2}] $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = 3.16 \pm 0.5 \times 10^6 \exp ( - 10500 \pm 1000{\rm cal/}RT){\rm M}^{{\rm - 1}} {\rm s}^{{\rm - 1}} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm \gamma }_{{\rm CF}_{\rm 2} {\rm CCI}_{\rm 2} } :{\rm \gamma }_P :{\rm \gamma }_{{\rm C}_{\rm 2} {\rm F}_{\rm 5} {\rm CI}} :{\rm \gamma }_{{\rm CCL}_{\rm 3} } :{\rm \gamma }_{{\rm CF}_{\rm 4} } :{\rm \gamma }_{{\rm N}_{\rm 2} } = 1:0.22:0.15:0.14:0.054:0.015 $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm \gamma }_{{\rm NO}_{\rm 2} } 〈 0.01 $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ k_3 = 1.4 \pm 0.3 \times 10^8 {\rm s}^{{\rm - 1}} $$\end{document}
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 18 (1986), S. 1323-1331 
    ISSN: 0538-8066
    Schlagwort(e): Chemistry ; Physical Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The thermal addition of CF3O3CF3(T) to CF2CCl2(E) has been investigated between 49.6 and 69.5°C. The initial pressure of CF3O3CF3 was varied between 7 and 240 torr and that of CF2CCl2 between 4 and 600 torr. Four products of formula CF3O(E)j OOCF3, where j = 1 → 4 are formed. The sum of the products Σi = 14 CF3O(E)jOOCF3 is equal to the amount of trioxide decomposed.The reaction is homogeneous. Its rate is not affected by the total pressure and the presence of inert gas. It is a free radical telomerization with four basic steps: thermal decomposition of CF3O3CF3 into CF3O. and CF3O2., chain initiation by addition of CF3O. to olefin incorporated in, and telomeric radicals termination.The consumption of alkene is well represented by the equation: \documentclass{article}\pagestyle{empty}\begin{document}$$ - d[E]/dt = k_1 [T]\left\{ {1 + \sum\limits_{j = 1}^3 {\prod\limits_{i = 1}^j {[1 + (k_{t_1 } k_1^{1/2} /k_{gi} } k_t^{1/2})([T]^{1/2} /[E])]^{ - 1} } } \right\} $$\end{document} where (d[E]/d[T]) = \documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document} is the mean chain length of telomerization. \documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document} varies from 1.45 at 1.5 torr of E to 3.3 at 400 torr of E. Above this pressure E has no influence on \documentclass{article}\pagestyle{empty}\begin{document}$$ \bar n $$\end{document}.The estimated value of the constant for the addition of telomeric radicals to alkene is:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_g \simeq 8.6 \pm 6.0 \times 10^4 \exp ( - 2300 \pm 200{\rm col mol}^{{\rm - 1}} /RT){\rm M}^{{\rm - 1}} {\rm s}^{{\rm - 1}} $$\end{document}
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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