Chemistry of the cyclopentoxy and cyclohexoxy radicals at subambient temperatures
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.
- Research Organization:
- National Center for Atmospheric Research, Boulder, CO (US)
- OSTI ID:
- 20075892
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 104, Issue 21; Other Information: PBD: 1 Jun 2000; ISSN 1089-5639
- Country of Publication:
- United States
- Language:
- English
Similar Records
Modeling–Experiment–Theory Analysis of Reactions Initiated from Cl + Methyl Formate
A Theoretical Investigation of the Structure and Reactivity of the Molecular Constituents of Oil Sand and Oil Shale