Journal
JOURNAL OF PHYSICAL CHEMISTRY A
Volume 113, Issue 25, Pages 6979-6986Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jp902458d
Keywords
-
Funding
- U.S. Air Force Phase II STTR program [FA8650-06C-2658]
Ask authors/readers for more resources
The kinetics of benzoxyl radical decomposition was studied using ab initio computational chemistry and RRKM rate theory. The benzoxyl radical is an important but short-lived intermediate in the combustion of toluene and other alkylated aromatic hydrocarbons. A theoretical study of the thermochemistry and kinetics to products over a range of temperatures and pressures for benzoxyl decomposition is reported. Ab initio calculations with the G3X theoretical method reveal low-energy pathways from the benzoxyl radical to benzaldehyde + H and the phenyl radical + formaldehyde (CH2O), as well as a novel mechanism to benzene + the formyl radical ((HCO)-O-center dot). RRKM simulations were performed for benzoxyl decomposition as a function of temperature and pressure. Benzaldehyde formation constitutes more than 80% of the total reaction products at temperatures below 1000 K, decreasing to around 50% at 2000 K. Formation of benzene + (HCO)-O-center dot and phenyl + CH2O is of similar importance, each accounting for 5-10% of the decomposition products at around 1000 K, increasing to 20-30% at 2000 K. The results presented here should lead to improved kinetic models for the oxidation of alkylated aromatic hydrocarbons, particularly for the formation of benzene as a direct oxidation product of toluene. Re-evaluation of the phenyl radical heat of formation leads us to suggest a benzene C-H bond dissociation energy in the range of 113.5-114.5 kcal mol(-1).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available