High-temperature reactions of phenyl oxidation
- Deutsche Forschungsanstalt fuer Luft-und Raumfahrt, Stuttgart (Germany). Inst. fuer Physikalische Chemie der Verbrennung
The reactions of phenyl radicals with molecular and atomic oxygen have been studied in the temperature range 900--1,800 K behind reflected shocks. The total pressure ranged from 1.3 to 2.5 bar. Phenyl radicals were generated by the fast thermal decomposition of nitroso- or iodobenzene. Resonance absorption was used to record the temporal concentration profiles of H, O, and I atoms and of CO molecules. This sensitive technique allowed study of the reaction systems under favorable conditions by applying very low initial concentrations (0.5--250 ppm). Due to the complexity of the system, it was necessary to study in a separate series of experiments the dissociation reactions of intermediates like phenoxy radicals and p-quinone. For the initiation reaction C{sub 6}H{sub 5} + O{sub 2}, two product channels were found: C{sub 6}H{sub 5} + O{sub 2} = C{sub 6}H{sub 5}O + O (R1) and a fast channel, producing H-atoms, C{sub 6}H{sub 5} + O{sub 2} = C{sub 6}H{sub 4}O{sub 2} + H (R2) with a branching ratio k{sub 1}/k{sub 2} of about 3 in the investigated temperature range. Reaction (R2) seems plausible; however, it presently has the status of a working hypothesis. For C{sub 6}H{sub 5} + O = C{sub 5}H{sub 5} + CO (R5) a rate constant of about 10{sup 14} cm{sup 3}/mol times s was deduced. From the evaluated data, a reaction scheme for phenyl radicals is given, which is expected to improve the modeling results of practical flames containing benzene or other aromatics.
- OSTI ID:
- 93230
- Report Number(s):
- CONF-940711--
- Country of Publication:
- United States
- Language:
- English
Similar Records
INVESTIGATION OF THE CONTRIBUTION OF PHENYL RADICALS TO REACTIONS IN SOLUTION WITH THE HELP OF DEUTERIUM
Reactions of phenoxy radicals in the gas phase