Imaging the dynamics of reactions between Cl atoms and the cyclic ethers oxirane and oxetane

Pearce, Julie K., Retail, Bertrand, Greaves, Stuart J., Rose, Rebecca A. and Orr-Ewing, Andrew J. (2007) Imaging the dynamics of reactions between Cl atoms and the cyclic ethers oxirane and oxetane. Journal of Physical Chemistry A, 111 51: 13296-13304. doi:10.1021/jp0773684

Author Pearce, Julie K.
Retail, Bertrand
Greaves, Stuart J.
Rose, Rebecca A.
Orr-Ewing, Andrew J.
Title Imaging the dynamics of reactions between Cl atoms and the cyclic ethers oxirane and oxetane
Journal name Journal of Physical Chemistry A   Check publisher's open access policy
ISSN 1089-5639
Publication date 2007-12
Sub-type Article (original research)
DOI 10.1021/jp0773684
Volume 111
Issue 51
Start page 13296
End page 13304
Total pages 9
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract Direct current slice velocity map ion images of the HCl(v‘ = 0, J‘) products from the photoinitiated reactions of ground state Cl atoms with ethane, oxirane (c-C2H4O), and oxetane (c-C3H6O), at respective mean collision energies of 5.5, 6.5, and 7.3 kcal mol-1, were analyzed using a Legendre moment fitting procedure. The experimental method and the fitting technique were tested by comparing the derived center-of-mass (CM) frame angular scattering distribution for the HCl(v‘ = 0, J‘ = 1) products from the reaction of Cl + C2H6 with those determined by Suits and co-workers from a crossed molecular beam experiment. For the Cl + c-C2H4O reaction, a broad, forward, and backward peaking CM frame angular distribution of HCl(v‘ = 0, J‘ = 2) products was determined, with an average fraction of the available energy released as product translational energy of ft, equal to 0.52 ± 0.18. The HCl consumes only 1% of the available energy, and conservation arguments dictate that the radical coproduct is significantly internally excited, corresponding to an average fraction of the available energy of fint(c-C2H3O), equal to 0.47 ± 0.18. For the reaction of oxetane with Cl atoms, abstraction of H atoms is possible from carbon atoms from positions either α or β to the O atom. The contributions to the reaction from these two H-atom abstraction channels were estimated to be 63 and 37%, consistent with an unbiased propensity for removal of α- and β-H atoms that are present in 2:1 abundance. The angular scatter of products in the CM frame is also broad and forward−backward peaking and is reminiscent of the products of the Cl + CH3OH and CH3OCH3 reactions. The derived mean fraction of the available energy channelled into product translation is ft = 0.54 ± 0.12 for each of the two abstraction pathways. With only a small amount of energy in the rotation of the HCl(v‘ = 0), the remainder is accounted for by excitation of the radical coproduct internal modes, with fint(c-C3H5O) = 0.42 ± 0.12 for both α- and β-H abstraction. The broad product scattering in the CM frame observed for both reactions of Cl atoms with the cyclic ethers is consistent with reactive collisions over a wide range of impact parameters, as might be expected for barrierless reactions with loose transition states.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
School of Chemistry and Molecular Biosciences
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Citation counts: TR Web of Science Citation Count  Cited 10 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 11 Jun 2013, 16:01:47 EST by Dr Julie Pearce on behalf of School of Earth Sciences