Hydroxide radical oxidation of isoprene

Gu, Chee Liang; Rynard, Carolyn M.; Hendry, Dale G.; Mill, Theodore

doi:10.1021/es00132a007

Cited by 96 publications

(72 citation statements)

References 13 publications

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“…lo-'' cm3 molec-' s -' from the isoprene and NOz data, respectively, yielding an average value of 1.8 x lo-'' cm3 molec-' s-'. This result is in good agreement with the results of previous studies, which range from k. = 1.0 X lo-'' to k. = 1.8 x lo-'' cm3 molec-' s-l [6,. The reaction is quite slow, and, hence, may suffer some contamination from other radicals that form in small quantities; for example HOZ and subsequently OH, explaining the somewhat higher rate constant derived from the isoprene data relative to that derived from the NOz data.…”

Section: Ground State Atomic Oxygen-isoprene Reactionsupporting

confidence: 93%

“…Atkinson's work [16] indicates that OH reaction rate constants correlate very well with O(3P) rate constants for a wide range of compounds, hence the uncertainty in this and other estimated O(3P) rate constants is relatively small. While OH and NO2 may lead to roughly the same products, the product distribution from the 0(3P)-isoprene reaction (discussed below) is dramatically different from that which has been previously observed from the OH-isoprene reaction [6,7].…”

Section: Formation Of O F P ) In the Methyl Nitrite-high No Systemmentioning

confidence: 65%

“…The remaining alkyl radicals undergo various isomerizations to form 3-methyl furan, the multisubstituted compounds found in the aerosol phase, and in all likelihood several other minor products. It is unlikely that the studies of the OH-isoprene reaction carried out as part of this work, Tuazon and Atkinson [7], and Gu et al [6], which have collectively included GC/MS, GC/FID, and FTIR analyses, have failed to identify other major reaction products (e.g., more than 5-10% each). One possible reaction pathway for the remaining carbon is via the same allyl radical intermediate that leads to the formation of 2-methyl 2-butenal from the 0(3P)-isoprene reaction, discussed below, and has been proposed as one of the pathways to explain the formation of 3-methyl furan [6].…”

Section: Calculations Of Carbonyl and Furan Yieldsmentioning

confidence: 86%

“…The results of our two laboratories are therefore in excellent agreement as to the yields of methacrolein and methyl vinyl ketone, and 3-methyl furan. The methacrolein, methyl vinyl ketone, and 3-methyl furan yields of Gu et al [6] at about 0.23, 0.17, and 0.032, respectively, show the same proportions as those from this work and Tuazon and Atkinson [7], but are lower, probably due to O(3P) or possibly other artifacts in the Gu et al a These species are unidentified peaks that elute from the GC between 2-ethenyl 2-methyl oxirane and 2-(l-methylethenyl) oxirane.…”

Section: Calculations Of Carbonyl and Furan Yieldsmentioning

confidence: 96%

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Atmospheric photooxidation of isoprene part I: The hydroxyl radical and ground state atomic oxygen reactions

Paulson

Flagan

Seinfeld

1992

Int J of Chemical Kinetics

204

186

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The OH reaction with isoprene is studied. Methyl nitrite photolysis experiments were carried out in an outdoor smog chamber in a n attempt to identify as completely as possible OHisoprene product distribution. Emphasis was placed on identification and quantification of oxygenated products. A Tenax-based cryo-trap thermal desorber used to trap, concentrate, and dry chamber samples for identification on a GC/MS is described. Analysis of the products revealed that O(3P) can form in reaction systems designed to study OH reactions that include high concentrations of NO, and consequently NOz, hence, this reaction is also examined. The yields of methacrolein and methyl vinyl ketone are determined as 25 t 3 and 35.5 t 4%, respectively, with an additional 4 t 2% as 3-methyl furan, totaling 65 t 4%. These results, combined with those of previous studies allow 80% of isoprene's products to be explicitly identified, and the general structure of the remaining products to be ascertained. The O(3P) reaction produces 84 5 8% epoxides, and 8 t 3% species which result in production of HOa, and subsequently, OH. A heretofore unidentified product of the O(3P) reaction, 2-methyl2-butenal, is identified. The rate constant of the N02-isoprene reaction is measured.

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Section: Ground State Atomic Oxygen-isoprene Reactionsupporting

confidence: 93%