کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
241138 1427923 2013 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Synchrotron photoionization measurements of fundamental autoignition reactions: Product formation in low-temperature isobutane oxidation
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Synchrotron photoionization measurements of fundamental autoignition reactions: Product formation in low-temperature isobutane oxidation
چکیده انگلیسی

Product formation in laser-photolytic Cl-initiated low-temperature (550–700 K) oxidation of isobutane in a slow-flow reactor was investigated by tunable synchrotron photoionization mass spectrometry. These experiments probed the time-resolved formation of products following photolytic initiation of the oxidation, and identify isomeric species by their photoionization spectra. The relative yields of oxygenated product isomers (2,2-dimethyloxirane, methylpropanal, and 3-methyloxetane) are in reasonable concord with measurements from Walker and co-workers (J. Chem. Soc. Faraday Trans. 74 (1) (1978) 2229–2251) at higher temperature. Oxidation of isotopically labeled isobutane, (CH3)3CD, suggests that methylpropanal formation can proceed from both (CH3)2CCH2OOH and CH3CH(CH2)CH2OOH isomers. Bimodal time behavior is observed for product formation; the initial prompt formation reflects “formally direct” channels, principally chemical activation, and the longer-timescale “delayed” component arises from dissociation of thermalized ROO and QOOH radicals. The proportion of prompt to delayed signal is smaller for the oxygenated products than for the isobutene product. This channel-specific behavior can be qualitatively understood by considering the different energetic distributions of ROO and QOOH in formally direct vs. thermal channels and the fact that the transition states involved in the formation of oxygenated products are “tighter” than that for isobutene formation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Proceedings of the Combustion Institute - Volume 34, Issue 1, 2013, Pages 385–392
نویسندگان
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