TY  - JOUR
AU  - Nehr, S.
AU  - Bohn, B.
AU  - Wahner, A.
TI  - Promt HO2 Formation Following the Reaction of OH Aromatic Compounds under Atmospheric conditions
JO  - The journal of physical chemistry  / A
VL  - 116
IS  - 24
SN  - 1089-5639
CY  - Washington, DC
PB  - Soc.
M1  - PreJuSER-22452
SP  - 6015 - 6026
PY  - 2012
N1  - We thank M. Bachner, H. Fuchs, A. Hofzumahaus, F. Holland, and S. Lou for useful discussions and technical support. S.N. thanks the Deutsche Forschungsgemeinschaft for a Ph.D. studentship under grant BO 1580/3-1.
AB  - The secondary formation of HO(2) radicals following OH + aromatic hydrocarbon reactions in synthetic air under normal pressure and temperature was investigated in the absence of NO after pulsed production of OH radicals. OH and HO(x) (=OH + HO(2)) decay curves were recorded using laser-induced fluorescence after gas-expansion. The prompt HO(2) yields (HO(2) formed without preceding NO reactions) were determined by comparison to results obtained with CO as a reference compound. This approach was recently introduced and applied to the OH + benzene reaction and was extended here for a number of monocyclic aromatic hydrocarbons. The measured HO(2) formation yields are as follows: toluene, 0.42 ± 0.11; ethylbenzene, 0.53 ± 0.10; o-xylene, 0.41 ± 0.08; m-xylene, 0.27 ± 0.06; p-xylene, 0.40 ± 0.09; 1,2,3-trimethylbenzene, 0.31 ± 0.06; 1,2,4-trimethylbenzene, 0.37 ± 0.09; 1,3,5-trimethylbenzene, 0.29 ± 0.08; hexamethylbenzene, 0.32 ± 0.08; phenol, 0.89 ± 0.29; o-cresol, 0.87 ± 0.29; 2,5-dimethylphenol, 0.72 ± 0.12; 2,4,6-trimethylphenol, 0.45 ± 0.13. For the alkylbenzenes HO(2) is the proposed coproduct of phenols, epoxides, and possibly oxepins formed in secondary reactions with O(2). In most product studies the only quantified coproducts were phenols whereas only a few studies reported yields of epoxides. Oxepins have not been observed so far. Together with the yields of phenols from other studies, the HO(2) yields determined in this work set an upper limit to the combined yields of epoxides and oxepins that was found to be significant (≤0.3) for all investigated alkylbenzenes except m-xylene. For the hydroxybenzenes the currently proposed HO(2) coproducts are dihydroxybenzenes. For phenol and o-cresol the determined HO(2) yields are matching the previously reported dihydroxybenzene yields, indicating that these are the only HO(2) forming reaction channels. For 2,5-dimethylphenol and 2,4,6-trimethylphenol no complementary product studies are available.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:22195640
UR  - <Go to ISI:>//WOS:000305444100029
DO  - DOI:10.1021/jp210946y
UR  - https://juser.fz-juelich.de/record/22452
ER  -