Molecules 2013, 18(11), 13608-13622; doi:10.3390/molecules181113608
Article

Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction

Received: 27 August 2013; in revised form: 17 October 2013 / Accepted: 22 October 2013 / Published: 4 November 2013
(This article belongs to the Special Issue Gas Phase Reactions)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Photochemically driven reactions involving unsaturated radicals produce a thick global layer of organic haze on Titan, Saturn’s largest moon. The allyl radical self-reaction is an example for this type of chemistry and was examined at room temperature from an experimental and kinetic modelling perspective. The experiments were performed in a static reactor with a volume of 5 L under wall free conditions. The allyl radicals were produced from laser flash photolysis of three different precursors allyl bromide (C3H5Br), allyl chloride (C3H5Cl), and 1,5-hexadiene (CH2CH(CH2)2CHCH2) at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re-) combination pathway C3H5+C3H5 → C6H10 we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C3H5Br. A kinetic analysis indicates that the end product formation is influenced by specific reaction kinetics of photochemically activated allyl radicals. Above 10 mbar the (re-) combination pathway becomes dominant. These findings exemplify the specificities of reaction kinetics involving chemically activated species, which for certain conditions cannot be simply deduced from combustion kinetics or atmospheric chemistry on Earth.
Keywords: allyl radical; allyl self-reaction; aerosol precursor chemistry
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MDPI and ACS Style

Seidel, L.; Hoyermann, K.; Mauß, F.; Nothdurft, J.; Zeuch, T. Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction. Molecules 2013, 18, 13608-13622.

AMA Style

Seidel L, Hoyermann K, Mauß F, Nothdurft J, Zeuch T. Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction. Molecules. 2013; 18(11):13608-13622.

Chicago/Turabian Style

Seidel, Lars; Hoyermann, Karlheinz; Mauß, Fabian; Nothdurft, Jörg; Zeuch, Thomas. 2013. "Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction." Molecules 18, no. 11: 13608-13622.

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