The reaction between CzH5 and 0 2 a t 295 K has been studied with a flow reactor sampled by a mass spectrometer. With helium as the carrier gas the rate coefficient was found to increase from (1.2 f 0.3) X cm3/s as [He] was increased from 2 X 10I6 to 3.4 X 1017The importance of to (3.6 f 0.9) X (Ib) relative tohas been determined from a knowledge of the initial CzHs concentration together with a measurement of the CzH4 produced in reaction (5). F, the fraction of the C2Hs radicals removed by path (5), was found to decrease from 0.15 to 0.06 as [He] increased from 2 X 10I6 to 3.4 X 1017 The rate coefficient for reaction (5) was found to be independent of [He] and to have a value of (2.1 f 0.5) X cm3/s. The variation in F reflects the fact that k Ib increases as [He] increases. These observations are taken as evidence for a direct mechanism for C2H4 production and a collision-stabilized route for CzH5O2 formation. Calculations indicate that the high-pressure limit for reaction ( l b ) is -4.4 X cm3/s and that in the polluted troposphere the branching ratio for reactions ( l b ) and (5) will be -20.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.