Gas-Phase Reaction Kinetics of the Ortho and Ipso Adducts 1,2,4,5-Tetramethylbenzene-OH with O-2
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F21%3A00122890" target="_blank" >RIV/00216224:14310/21:00122890 - isvavai.cz</a>
Result on the web
<a href="https://pubs.acs.org/doi/10.1021/acsearthspacechem.1c00230" target="_blank" >https://pubs.acs.org/doi/10.1021/acsearthspacechem.1c00230</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acsearthspacechem.1c00230" target="_blank" >10.1021/acsearthspacechem.1c00230</a>
Alternative languages
Result language
angličtina
Original language name
Gas-Phase Reaction Kinetics of the Ortho and Ipso Adducts 1,2,4,5-Tetramethylbenzene-OH with O-2
Original language description
The reversible reaction of OH radicals with 1,2,4,5-tetramethylbenzene (1245-TeMB, durene) leads to adducts at the substituted (ipso) and unsubstituted (ortho) positions of the ring. By the use of flash photolysis for production and resonance fluorescence for detection of OH, the gas-phase reactions of O-2 with these adducts were investigated over the temperature range of 300-340 K in He at 200 mbar. The decay of OH, generated by pulsed vacuum-UV photolysis of H2O, was monitored under slow-flow conditions in the presence of 1245-TeMB and O-2 at concentrations of up to 19 X 10(12) CM-3 and 2 X 10(16) cm(-3), respectively. Triexponential OH decays resulted from the unimolecular decomposition of the two adducts, representing OH reservoirs with different stabilities. In the presence of O-2, additional adduct loss pathways exist, leading to faster OH consumption. Triexponential functions fitted to these decays were analyzed to obtain rate constants for the reactions of O-2 with both adducts. Rate constants in the range of (4-13) x 10(-15) and (0.3-3) x 10(-15) cm(3)s(-1) were obtained for the ortho and the ipso adducts, respectively, depending on temperature and assumptions regarding details of the underlying mechanism of adduct isomer formation and isomerization. At O-2 concentrations exceeding about 1 x 10(16) cm(-3), deviations from a linear dependence of the adduct loss rates on the O-2 concentration indicate an even more complex mechanism. The validity of the rate constants is therefore confined to O-2 concentrations below 1 X 10(16) cm(-3). The adduct + O-2 rate constants for 1245-TeMB are greater than the corresponding previously obtained rate constants for benzene, toluene, and p- and m-xylene but smaller than those for hexamethylbenzene. The results are discussed in terms of the current knowledge about the mechanism of OH-induced degradation of aromatic compounds in the presence of O-2.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10508 - Physical geography
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
ACS EARTH AND SPACE CHEMISTRY
ISSN
2472-3452
e-ISSN
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Volume of the periodical
5
Issue of the periodical within the volume
9
Country of publishing house
US - UNITED STATES
Number of pages
9
Pages from-to
2243-2251
UT code for WoS article
000697335600006
EID of the result in the Scopus database
2-s2.0-85114677596