Premium
Hydrogen/deuterium abstraction by chlorine atoms from gaseous ethyl chlorides. Secondary kinetic isotope effects in the system CH 3 CH 2 Cl, CH 3 CHDCl, CH 3 CD 2 Cl
Author(s) -
Niedzielski J.,
TschuikowRoux E.,
Yano T.
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.550160602
Subject(s) - chemistry , deuterium , kinetic isotope effect , arrhenius equation , reaction rate constant , chlorine , atmospheric temperature range , hydrogen , chlorine atom , kinetic energy , hydrogen atom abstraction , methane , chemical kinetics , analytical chemistry (journal) , kinetics , activation energy , thermodynamics , atomic physics , medicinal chemistry , organic chemistry , physics , quantum mechanics
The abstraction of hydrogen/deuterium from CH 3 CH 2 Cl, CH 3 CHDCl, and CH 3 CD 2 Cl by photochemically generated ground‐state chlorine atoms has been investigated over the temperature range of 8–94°C using methane as a competitor. Rate constant data for the following reactions have been obtained:The temperature dependence of the relative rate constants k i / k j was found to conform to the Arrhenius rate law, where the stated error limits are one standard deviation:\documentclass{article}\pagestyle{empty}\begin{document}$$ k_1 /k_2 = (1.099 \pm 0.015)\exp [(429 \pm 2)/T] $$ $$ k_1 /k_r = (1.422 \pm 0.026)\exp [(1113 \pm 3)/T] $$ $$ k_2 /k_r = (1.295 \pm 0.029)\exp [(684 \pm 3)/T] $$ $$ k_3 /k_r = (1.177 \pm 0.025)\exp [(717 \pm 4)/T] $$ $$ k_4 /k_r = (1.115 \pm 0.023)\exp [(732 \pm 2)/T] $$ $$ k_5 /k_r = (0.978 \pm 0.020)\exp [(985 \pm 2)/T] $$\end{document}and k r is the rate constant for the reference reaction (CH 4 + Cl → CH 3 + HCl). The β secondary kinetic isotope effects (k 2 /k 3 /k 4 ) are close to unity and show a slight inverse temperature dependence. Both preexponential factors and activation energies decrease as a result of deuterium substitution in the adjacent chloromethyl group. The trends are well outside the limits of experimental error.