ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The kinetics of the H2-OF2 reaction was studied in the temperature range of 160°-310°C at 1 atm total pressure in a magnesium stirred-flow reactor. Initial concentration ranges were 1/2-1/2 mol·% OF2, 3/16-5 mol·% H2, and 1/4-5.0 mol·% O2; helium was used as the diluent. When the reactants were in a mole ratio of 3/2 (H2/OF2), the rate of disappearance of H2 was 1.5 times that of OF2, consistent with the previously reported stoichiometry. The rate of disappearance of OF2 was strongly influenced by OF2 concentration, weakly influenced by H2 concentration, and inhibited by the oxygen formed in the reaction. An increase in the surface area did not produce a significant change in the rate of reaction. These concentration dependencies led to a proposed ten-step mechanism from which was derived the following rate equation: \documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{- d(\rm {OF}_2)}}{{dt}} = \frac{{k_0 (\rm {OF}_2)^2}}{{(\rm {O}_2)^{1/2}}}\left(1 + \frac{{\alpha (\rm {OF}_2)}}{{\alpha (\rm {OF}_2) + \beta (\rm {H}_2)}}\right) $$\end{document} where k0 is a complex combination of elementary rate constants and α and β are elementary rate constants. An Arrhenius treatment of k0 gave \documentclass{article}\pagestyle{empty}\begin{document}$$ k_0 = 10^{8.41 \pm 0.24} \exp (- 17,300 \pm 500/RT)(\rm {l}./\rm {mol})^{1/2} /\sec $$\end{document}These experimental Arrhenius parameters are lower than those predicted from reported and estimated elementary rate constants. The possibility of heterogeneous contributions is discussed.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550100710
