ISSN:
0538-8066
Schlagwort(e):
Chemistry
;
Physical Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The kinetics of the thermal reaction between CF3OF and C3F6 have been investigated between 20 and 75°C. It is a homogeneous chain reaction of moderate length where the main product is a mixture of the two isomers 1-C3F7OCF3 (68%) and 2-C3F7OCF3 (32%). Equimolecular amounts of CF3OOF3 and C6F14 are formed in much smaller quantities. Inert gases and the reaction products have no influence on the reaction, whereas only small amounts of oxygen change the course of reaction and larger amounts produce explosions.The rate of reaction can be represented by eq. (I): The following mechanism explains the experimental results: Reaction (5) can be replaced by reactions (5a) and (5b), without changing the result: Reaction (4) is possibly a two-step reaction: \documentclass{article}\pagestyle{empty}\begin{document}$$ E_1 = 15.90 \pm 0.45{\rm kcal}\,{\rm mol}^{ - 1} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 = \left( {7.60 \pm 0.68} \right)10^8 {\rm exp}\left( { - 15,900\,\, \pm \,\,450\,\,{{{\rm cal}} \mathord{\left/ {\vphantom {{{\rm cal}} {RT}}} \right. \kern-\nulldelimiterspace} {RT}}} \right)M^{ - 1} \cdot s^{ - 1} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ E^ * \, = \,12.30\, \pm \,0.25\,{\rm kcal}\,{\rm mol}^{ - 1} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ k^ * \, = \,\left( {6.11\, \pm \,0342} \right)10^7 \,{\rm exp}\left( { - 12,300\, \pm \,250\,{{{\rm cal}} \mathord{\left/ {\vphantom {{{\rm cal}} {RT}}} \right. \kern-\nulldelimiterspace} {RT}}} \right)M^{ - 1} \, \cdot \,{\rm s}^{ - 1} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {E^ * \, - \frac{1}{2}E_1 \, = \,4.35\,{\rm kcal}\, = \,E_3 \, - \,\frac{1}{2}E_4 ;} & {E_3 \,} \\ \end{array} 〉 \,4.35\,{\rm kcal} $$\end{document} \documentclass{article}\pagestyle{empty}\begin{document}$$ \nu \,\left( {{\rm chain}\,{\rm length}} \right)\, = \,1 + \,\frac{{k_3 }}{{k_1 ^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} \left( {2k_4 } \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} }}\left( {\frac{{\left| {{\rm CR}_{\rm 3} {\rm OF}} \right|}}{{\left| {{\rm C}_{\rm 3} {\rm F}_{\rm 6} } \right|}}} \right)^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} $$\end{document} For ∣CF3 = ∣C3F6∣, ν20°C = 36.8, ν50°C = 24.0, and ν70°C = 14.2.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/kin.550160203
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