Branching ratios in the hydroxyl reaction with propene

Document Type

Article

Publication Date

3-31-2011

Abstract

The branching ratios for the reactions of attachment of hydroxyl radical to propene and hydrogen-atom abstraction were measured at 298 K over the buffer gas pressure range 60-400 Torr (N2) using a subatmospheric pressure turbulent flow reactor coupled with a chemical ionization quadrupole mass spectrometer. Isotopically enriched water H218O was used to produce 18O-labeled hydroxyl radicals in reaction with fluorine atoms. The β-hydroxypropyl radicals formed in the attachment reactions 1aand 1b, OH + C3H6 → CH2(OH) C•HCH3 (eq 1a) and OH + C3H6 → C•H2CH(OH)CH3 (eq 1b), were converted to formaldehyde and acetaldehyde in a sequence of secondary reactions in O2- and NO-containing environment. The 18O-labeling propagates to the final products, allowing determination of the branching ratio for the attachment channels of reaction 1. The measured branching ratio for attachment is β1b = k1b/(k1a + k1b) = 0.51 ± 0.03, independent of pressure over the 60-400 Torr pressure range. An upper limit on the hydrogen-abstraction channel, OH + C3H6 → H2O + C3H5 (eq 1c), was determined by measuring the water yield in reactions of OH and OD radicals (produced via H(D) + NO2 → OH(OD) + NO reactions) with C3H6 as k1c/(k1a + k1b + k1c) < 0.05 (at 298 K, 200 Torr N2). © 2011 American Chemical Society.

Identifier

79953037517 (Scopus)

Publication Title

Journal of Physical Chemistry A

External Full Text Location

https://doi.org/10.1021/jp107178n

e-ISSN

15205215

ISSN

10895639

First Page

2498

Last Page

2508

Issue

12

Volume

115

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