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CH 3 CH 2 SCH 3 + OH radicals: temperature‐dependent rate coefficient and product identification under atmospheric pressure of air
Author(s) -
OksdathMansilla Gabriela,
Peñéñory Alicia B.,
Albu Mihaela,
Barnes Ian,
Wiesen Peter,
Teruel Mariano A.
Publication year - 2010
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1714
Subject(s) - chemistry , radical , arrhenius equation , atmospheric temperature range , reaction rate constant , reactivity (psychology) , hydrogen atom abstraction , analytical chemistry (journal) , photodissociation , formaldehyde , atmospheric pressure , fourier transform infrared spectroscopy , adduct , hydrogen sulfide , photochemistry , sulfur , activation energy , kinetics , organic chemistry , thermodynamics , medicine , alternative medicine , oceanography , pathology , quantum mechanics , physics , geology
Relative rate coefficients have been determined for the gas‐phase reaction of hydroxyl (OH) radicals with ethyl methyl sulfide (EMS) using isobutene as a reference compound. The experiments were performed in a 1080 L quartz glass photoreactor in the temperature range of 286–313 K at a total pressure of 760 ± 10 Torr synthetic air using in situ FTIR absorption spectroscopy to monitor the concentration‐time behaviors of reactants and products. OH radicals were produced by the 254 nm photolysis of hydrogen peroxide (H 2 O 2 ). The kinetic data obtained were used to derive the following Arrhenius expression valid in the temperature range of 286–313 K (in units of cm 3 molecule −1 s −1 ): $k = (3.0 \pm 0.6) \times 10^{ - 15} \exp \left[ {{{(2457 \pm 65)} \mathord{\left/ {\vphantom {{(2457 \pm 65)} T}} \right. \kern-\nulldelimiterspace} T}} \right]$ The rate coefficient displays a negative temperature dependence and low pre‐exponential factor which supports the existence of an addition mechanism for the reaction involving reversible OH‐adduct formation. The results are compared with previous data of other sulfides from the literature and are rationalized in terms of structure–reactivity relationships. Additionally, product identification of the title reaction was performed for the first time by the FTIR technique under atmospheric conditions. Sulfur dioxide, formaldehyde, and formic acid were observed as degradation products in agreement with the two possible reaction channels (addition/abstraction). Copyright © 2010 John Wiley & Sons, Ltd.