OH-Initiated Oxidation of P-Xylene Under Atmospheric Conditions

Products of the Gas-Phase Reactions of OH Radicals with p-Xylene and 1,2,3- and 1,2,4-Trimethylbenzene: Effect of NO2 Concentration

“…As shown in Table 2, our present formation yield for p-tolualdehyde of 7.06 ( 0.42% is in general agreement with previous literature values 25,31,41 which are in the range 7.0-10.3% (Becker and Klein 29 have also reported a p-tolualdehyde yield obtained in the presence of NO x of 10%, but few experimental details were reported). Our present and previous 31 studies show that within the experimental errors the p-tolualdehyde formation yield is independent of the NO 2 concentration over the range (0.9-24) × 10 13 molecules cm -3 .…”

“…[6][7][8]45 Photolysis of cis-3-hexene-2,5-dione in the presence of cyclohexane (to scavenge any OH radicals present) showed a <3% loss of 3-hexene-2,5-dione over a 12 min irradiation period. However, in agreement with previous studies, 29,45 cis/trans photoisomerization occurred with conversion of 12% of the cis isomer to the trans isomer over the 12 min irradiation period employed. Because we observed ∼10% trans isomer to be initially present (possibly formed by cis/trans isomerization during the thermal desorption and analysis procedure), we choose to sum the cis and trans isomer products and report them as "3-hexene-2,5-dione".…”

“…Numerous product studies of the reactions of OH radicals with benzene, toluene, the xylenes, and trimethylbenzenes have been carried out. ,,− However, relatively few of these studies determined product yields under conditions where reaction of the OH−aromatic adducts with O 2 clearly dominated, ,,,,,, and product yields have been specifically measured as a function of the NO 2 concentration in only four studies. ,,, In this work, we have measured the formation yields of 2,3-butanedione (biacetyl) and/or 3-hexene-2,5-dione from the OH radical-initiated reactions of p -xylene and 1,2,3- and 1,2,4-trimethylbenzene, and of p -tolualdehyde and 2,5-dimethylphenol from p -xylene, as a function of NO 2 concentration.…”

Products of the OH Radical-Initiated Reaction of 3-Hexene-2,5-dione

“…In this work, we have extended our study of the OH radicalinitiated reactions of selected aromatic hydrocarbons (9) to investigate the products formed from reaction of 3-hexene-2,5-dione with OH radicals in the presence of NO. Using in situ Fourier transform infrared spectroscopic analyses, Becker and Klein (10) and Bierbach et al (12) observed the formation of methylglyoxal in 30-32% yield (as carbon) from the reaction of OH radicals with trans-3-hexene-2,5-dione in the presence of NO, while Tuazon et al (11) reported no evidence for methylglyoxal formation from either the cis-(<10% molar yield) or trans-(<15% molar yield) isomers. While there is an obvious discrepancy between these studies (10)(11)(12) concerning the formation of methylglyoxal, it is clear that formation of methylglyoxal is at most a relatively minor pathway and other products must account for the majority (g70%) of the 3-hexene- difficulty in identifying products from this reaction (10-13), we have used atmospheric pressure chemical ionization tandem mass spectrometry for product analyses.…”

Formation of ring‐retaining products from the OH radical‐initated reactions of o‐, m‐, and p‐xylene

“…The available ring-retaining product data are given in Table IV. The only literature data concern the formation ofp-tolualdehyde [27,30] …”