The effect of O2 and NO2 on the ring retaining products of the reaction of toluene with hydroxyl radicals

Moschonas, Nektarios; Danalatos, Demetrios; Glavas, Sotirios

doi:10.1016/s1352-2310(98)00134-4

Cited by 22 publications

(26 citation statements)

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“…The sum of the yields is somewhat less than 100%, which could be due to unquantified products or an overestimate of toluene reactivity. As discussed above, while the cresol, dienedial, and the epoxide products appear to be the result of primary OH/O 2 chemistry only, the final benzaldehyde product yield depends on both on 13 8.4 9.0 Klotz et al 14 5.8 17.9 Smith et al 15 6 15 23.8 16.7 Becker et al 16 7.1 3.7 4.4 Seuwen et al 17 5.3 52.9 4.1 5.5 Atkinson et al 18 12.3 Atkinson et al 19 6.45 25.2 Dumdei et al 20 5 2 7 1 4 Tuazon et al 21 10.5 14.6 Gery et al 22 9.8 10.6 Bandow et al 23 11 15 14 Shepson et al 24 5.4 8 7.5 Tuazon et al 25 11 the HO 2 and NO levels in the experiment. In light of this, it is perhaps not surprising that the present NO-free yield for benzaldehyde is lower than all of the previous measurements, most of which involved the presence of NO.…”

Section: Resultsmentioning

confidence: 89%

Primary Atmospheric Oxidation Mechanism for Toluene

et al. 2008

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The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique at temperatures ranging from 228 to 298 K. A major dienedial-producing pathway was detected for the first time for toluene oxidation, and glyoxal and methylglyoxal were found to be minor primary oxidation products. The results suggest that secondary oxidation processes involving dienedial and epoxide primary products are likely responsible for previous observations of glyoxal and methylglyoxal products from toluene oxidation. Because the dienedial-producing pathway is a null cycle for tropospheric ozone production and glyoxal and methylglyoxal are important secondary organic aerosol precursors, these new findings have important implications for the modeling of toluene oxidation in the atmosphere.

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Section: Resultsmentioning

confidence: 89%

Primary Atmospheric Oxidation Mechanism for Toluene

et al. 2008

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“…The recombination of the OH-adduct radical 1 and • NO2 is a fast reaction (77). Although this may subsequently lead to the formation of the nitrobenzene 17 with the expulsion of a water molecule (reaction 39) (78)(79)(80), it is conceivable that the hydroxynitrocyclohexadiene 16 reacts also in other ways (80). Its oxidation by, for example, • NO2 (reaction 40), might explain the formation of nitrophenol 19 (reaction 41), traces of which were observed earlier (78) in gas-phase work.…”

Section: Reactions In the Presence Of • No2mentioning

confidence: 99%

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

Mark

Schuchmann

et al. 2002

Environ. Sci. Technol.

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As a model for the electron-beam degradation of volatile aromatics (benzene, toluene, ethylbenzene, xylenes, BTEX) in groundwater strip gas, to be reported in Part 2, the gamma-radiolysis of benzene has been studied in aqueous solutions. Addition of *OH to the aromatic ring gives rise to hydroxycyclohexadienyl radicals which either dimerize or disproportionate. The various dimers undergo acid-catalyzed water elimination yielding biphenyl. Phenol is formed upon disproportionation directly, but also via dihydroxycyclohexadiene which subsequently undergoes acid-catalyzed water elimination. Co-radiolysis of benzene with nitrite generates *NO2 in addition to the hydroxycyclohexadienyl radical. These not only interact with one another (product: nitrobenzene via nitro-hydroxycyclohexadienes) but the *NO2 radical is also capable of abstracting cyclohexadienylic hydrogens. This reaction leads to the formation of 2- and 4-nitrophenol and to further nitrated products that were not identified. These are suggested to be formed in an analogous reaction of *NO2 with the hydroxycylohexadienyl dimers. The effect of O2 on these reactions and the relevance for the gas-phase radiolysis of BTEX is discussed.

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“…However, this results in lower benzaldehyde yields than observed under low-NO x conditions. The lack of observed NO x -dependence in the benzaldehyde yield may reflect a short lifetime of benzyl hydroperoxide, a high incidence of RO 2 + RO 2 reactions (Moschonas et al, 1999), a non-hydroperoxide-forming channel in the benzyl peroxy + HO 2 reaction (Baltaretu et al, 2009), or another pathway altogether (Salta et al, 2020). Regardless, to fit observations and further simplify the mechanism, we bypass the benzyl peroxy intermediate and form benzaldehyde directly from the reaction of toluene and xylene with OH with a fixed yield of 6%, consistent with most experimental results at both high and low NO x .…”

Section: Oxygenated Voc Yieldsmentioning

confidence: 99%

Development and evaluation of a new compact mechanism for aromatic oxidation in atmospheric models

Bates

Jacob

et al. 2021

Preprint

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Abstract. Aromatic hydrocarbons (mainly benzene, toluene, and xylenes) play an important role in atmospheric chemistry but the associated chemical mechanisms are complex and uncertain. Spare representation of this chemistry in models is needed for computational tractability. Here we develop a new compact mechanism for aromatic chemistry (GC13) that captures current knowledge from laboratory and computational studies with only 17 unique species and 44 reactions. We compare GC13 to six other currently used mechanisms of varying complexity in box model simulations of environmental chamber data and diurnal boundary layer chemistry, and show that GC13 provides results consistent with or better than more complex mechanisms for oxygenated products (alcohols, carbonyls, dicarbonyls), ozone, and hydrogen oxide (HOx ≡ OH + HO2) radicals. GC13 features in particular increased radical recycling and increased ozone destruction from phenoxy-phenylperoxy radical cycling relative to other mechanisms. We implement GC13 into the GEOS-Chem global chemical transport model and find higher glyoxal yields and net ozone loss from aromatic chemistry compared to other mechanisms. Aromatic oxidation in the model contributes 23 %, 5 %, and 8 % of global glyoxal, methylglyoxal, and formic acid production respectively, and has mixed effects on formaldehyde. It drives small decreases in global tropospheric OH (−2.2 %), NOx (≡ NO + NO2; −3.7 %) and ozone (−0.8 %), but a large increase in NO3 (+22 %) from phenoxy-phenylperoxy radical cycling. Regional effects in polluted environments can be substantially larger, especially from photolysis of carbonyls produced by aromatic oxidation, which drives large wintertime increases in OH and ozone concentrations.

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The effect of O2 and NO2 on the ring retaining products of the reaction of toluene with hydroxyl radicals

Cited by 22 publications

References 0 publications

Primary Atmospheric Oxidation Mechanism for Toluene

Primary Atmospheric Oxidation Mechanism for Toluene

Electron-Beam Treatment of Aromatic Hydrocarbons That Can Be Air-Stripped from Contaminated Groundwater. 1. Model Studies in Aqueous Solution

Development and evaluation of a new compact mechanism for aromatic oxidation in atmospheric models

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