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The Competitive dehydrohalogenation of 1,1,1‐trifluoro‐2‐chloroethane in reflected shock waves
Author(s) -
Millward G. E.,
TschuikowRoux E.
Publication year - 1972
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550040510
Subject(s) - chemistry , dehydrohalogenation , torr , hydrogen fluoride , hydrogen chloride , shock wave , thermal decomposition , shock tube , reaction rate constant , shock (circulatory) , decomposition , kinetics , hydrogen , chemical decomposition , analytical chemistry (journal) , inorganic chemistry , thermodynamics , organic chemistry , catalysis , medicine , physics , quantum mechanics
The thermal decomposition of 1,1,1‐trifluoro‐2‐chloroethane has been investigated in the single‐pulse shock tube between 1120° and 1300deg;K at total reflected shock pressures from ∼2610 to 3350 torr. Under these conditions, the major reaction is the α,α‐elimination of hydrogen chloride,\documentclass{article}\pagestyle{empty}\begin{document}$${\rm CF}_{\rm 3} {\rm CH}_{\rm 2} {\rm Cl}\mathop {{\rm \rightarrow}}\limits^{k_1 } {\rm CF}_{\rm 2} {\rm CHF} + {\rm HCl}$$\end{document} with\documentclass{article}\pagestyle{empty}\begin{document}$${\rm log(}k_1^\infty {\rm, sec}^{ - {\rm 1}} {\rm) = 13}{\rm .3} \pm {\rm 0}{\rm .4} - (65.5 \pm 2.2{\rm kcal})/2.303RT$$\end{document} The decomposition also involves the slower α,β‐elimination of hydrogen fluoride,\documentclass{article}\pagestyle{empty}\begin{document}$${\rm CF}_{\rm 3} {\rm CH}_{\rm 2} {\rm Cl}\mathop {{\rm \rightarrow}}\limits^{k_2 } {\rm CF}_{\rm 2} {\rm CHCl} + {\rm HF}$$\end{document} with the first‐order rate constant given by\documentclass{article}\pagestyle{empty}\begin{document}$${\rm log(}k_2^\infty {\rm, sec}^{ - {\rm 1}} {\rm) = 12}{\rm .7} \pm {\rm 0}{\rm .5} - (67.6 \pm 2.7{\rm kcal})/2.303RT$$\end{document} At temperatures above 1270°K, two additional minor products were observed. These were identified as CF 2 CFCl and CF 3 CHCl 2 and suggest CCl rupture as a third reaction channel leading to complicated kinetics.