Premium
Kinetics and equilibria of the reaction between bromine and ethyl ether. The CH bond dissociation energy in ethyl ether
Author(s) -
Kondo Osamu,
Benson Sidney W.
Publication year - 1984
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.550160802
Subject(s) - chemistry , ether , kinetics , bond dissociation energy , bromine , activation energy , kinetic energy , dissociation (chemistry) , atmospheric temperature range , medicinal chemistry , reaction rate constant , thermodynamics , organic chemistry , physics , quantum mechanics
Abstract The kinetics and equilibria of the reaction:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm Br} + {\rm CH}_{\rm 3} {\rm CH}_{\rm 2} {\rm OCH}_{\rm 2} {\rm CH}_{\rm 3} {\rm}\mathop {{\rm \rightleftharpoons}}\limits^{\rm 1} {\rm HBr} + {\rm CH}_{\rm 3} {\rm CHOCH}_{\rm 2} {\rm CH}_{\rm 3} $$\end{document}have been studied in the temperature range 298–333 K by using the very low pressure reactor (VLPR) technique. Combining the estimated entropy change of reaction (1), ΔS ° 1= 8.1 ± 1.0 eu, with the measured ΔG ° 1 , we find ΔH ° 1= 4.2 ± 0.4 kcal/mol; ΔH ° f (CH 3 CHOC 2 H 5 ) = −20.2 kcal/mol, and DH° [ Et OCH(Me)‐H] = 91.7 ± 0.4 kcal/mol. We find:\documentclass{article}\pagestyle{empty}\begin{document}$$ \log k_1 (1/{\rm mol s)} = 10.8(\pm 0.7) - (3.9 \pm 4.0)/\theta $$\end{document}where θ = 2.3 RT in kcal/mol. It has been shown that the reaction proceeds via a loose transition state and the “contact TS ” model calculation gives a very good agreement with the observed value.