ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The kinetics of the gas phase pyrolysis of dimethyl sulfide (DMS) was studied in a static system at 681-723 K by monitoring total pressure-time behavior. Analysis showed the pressure increase to follow DMS loss. The reaction follows two concurrent paths: with a slow, minor, secondary reaction: In a seasoned reactor the reaction follows a 3/2 order rate law with rate coefficient given by \documentclass{article}\pagestyle{empty}\begin{document}$$ \log [k({\rm L}^{{\raise0.7ex\hbox{${\rm 1}$} \!\mathord{\left/ {\vphantom {{\rm 1} {\rm 2}}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${\rm 2}$}}} /{\rm mol}^{{\raise0.7ex\hbox{${\rm 1}$} \!\mathord{\left/ {\vphantom {{\rm 1} {\rm 2}}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${\rm 2}$}}} {\rm s})] = 13.84 \pm 0.21 - (51.4 \pm 0.7)/\theta $$\end{document} with θ = 2.303 RT in kcal/mol. A free radical mechanism is proposed to account for the data and a theoretical rate coefficient is derived from independent data: \documentclass{article}\pagestyle{empty}\begin{document}$$\log [k({\rm L}^{{\raise0.7ex\hbox{${\rm 1}$} \!\mathord{\left/ {\vphantom {{\rm 1} {\rm 2}}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${\rm 2}$}}} /{\rm mol}^{{\raise0.7ex\hbox{${\rm 1}$} \!\mathord{\left/ {\vphantom {{\rm 1} {\rm 2}}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${\rm 2}$}}} {\rm s})] = 12.8 \pm 0.3 - (47 \pm 1.5)/\theta $$\end{document} which agrees well with the experimental one over the range studied. The reaction is initiated by Me2S → Me + MeS⋅ and propagated by metathetical radical attack on Me2S. C2H4 is formed by an isomerization reaction which may in part be due to a hot radical: Thermochemical data are listed, many from estimations, for both molecular and radical species of interest in the present system.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550170705
