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Title: Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures

Abstract

The Cl-atom initiated oxidation mechanisms of both cyclopentane and cyclohexane have been studied as a function of temperature using an environmental chamber/FTIR technique. The oxidation of cyclohexane leads to the formation of the cyclohexoxy radical, the chemistry of which is characterized by a competition between ring-opening (R5) and reaction with O{sub 2} (R6) to form cyclohexanone. The yield of cyclohexanone is shown to increase the decreasing temperature, and a rate coefficient ratio {kappa}{sub 6}/{kappa}{sub 5} = (1.3 {+-} 0.3) x 10{sup {minus}27} exp(5,550 {+-} 1,100/T) cm{sup 3} molecule{sup {minus}1} is obtained. The energy barrier to ring-opening is estimated to be 11.5 {+-} 2.2 kcal/mol. The dominant fate of the cyclopentoxy radical, formed in the Cl-atom initiated oxidation of cyclopentane, is ring-opening under all conditions studied here (230--300 K, 50--500 Torr O{sub 2}), with only a minor contribution from the O{sub 2} reaction at the lowest temperatures studied. The barrier to ring-opening for the cyclopentoxy radical is probably less than 10 kcal/mol.

Authors:
; ;
Publication Date:
Research Org.:
National Center for Atmospheric Research, Boulder, CO (US)
OSTI Identifier:
20075892
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory
Additional Journal Information:
Journal Volume: 104; Journal Issue: 21; Other Information: PBD: 1 Jun 2000; Journal ID: ISSN 1089-5639
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CHLORINE; ATOMS; OXIDATION; CHEMICAL REACTION KINETICS; CYCLOHEXANE; CYCLOALKANES; RADICALS; TEMPERATURE DEPENDENCE

Citation Formats

Orlando, J.J., Iraci, L.T., and Tyndall, G.S. Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures. United States: N. p., 2000. Web. doi:10.1021/jp0002648.
Orlando, J.J., Iraci, L.T., & Tyndall, G.S. Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures. United States. doi:10.1021/jp0002648.
Orlando, J.J., Iraci, L.T., and Tyndall, G.S. Thu . "Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures". United States. doi:10.1021/jp0002648.
@article{osti_20075892,
title = {Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures},
author = {Orlando, J.J. and Iraci, L.T. and Tyndall, G.S.},
abstractNote = {The Cl-atom initiated oxidation mechanisms of both cyclopentane and cyclohexane have been studied as a function of temperature using an environmental chamber/FTIR technique. The oxidation of cyclohexane leads to the formation of the cyclohexoxy radical, the chemistry of which is characterized by a competition between ring-opening (R5) and reaction with O{sub 2} (R6) to form cyclohexanone. The yield of cyclohexanone is shown to increase the decreasing temperature, and a rate coefficient ratio {kappa}{sub 6}/{kappa}{sub 5} = (1.3 {+-} 0.3) x 10{sup {minus}27} exp(5,550 {+-} 1,100/T) cm{sup 3} molecule{sup {minus}1} is obtained. The energy barrier to ring-opening is estimated to be 11.5 {+-} 2.2 kcal/mol. The dominant fate of the cyclopentoxy radical, formed in the Cl-atom initiated oxidation of cyclopentane, is ring-opening under all conditions studied here (230--300 K, 50--500 Torr O{sub 2}), with only a minor contribution from the O{sub 2} reaction at the lowest temperatures studied. The barrier to ring-opening for the cyclopentoxy radical is probably less than 10 kcal/mol.},
doi = {10.1021/jp0002648},
journal = {Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory},
issn = {1089-5639},
number = 21,
volume = 104,
place = {United States},
year = {2000},
month = {6}
}