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Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction
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 persp...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6270213/ https://www.ncbi.nlm.nih.gov/pubmed/24192913 http://dx.doi.org/10.3390/molecules181113608 |
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author | Seidel, Lars Hoyermann, Karlheinz Mauß, Fabian Nothdurft, Jörg Zeuch, Thomas |
author_facet | Seidel, Lars Hoyermann, Karlheinz Mauß, Fabian Nothdurft, Jörg Zeuch, Thomas |
author_sort | Seidel, Lars |
collection | PubMed |
description | 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 (C(3)H(5)Br), allyl chloride (C(3)H(5)Cl), and 1,5-hexadiene (CH(2)CH(CH(2))(2)CHCH(2)) at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re-) combination pathway C(3)H(5)+C(3)H(5) → C(6)H(10) we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C(3)H(5)Br. 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. |
format | Online Article Text |
id | pubmed-6270213 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-62702132018-12-20 Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction Seidel, Lars Hoyermann, Karlheinz Mauß, Fabian Nothdurft, Jörg Zeuch, Thomas Molecules Article 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 (C(3)H(5)Br), allyl chloride (C(3)H(5)Cl), and 1,5-hexadiene (CH(2)CH(CH(2))(2)CHCH(2)) at 193 nm. Stable products were identified by their characteristic vibrational modes and quantified using FTIR spectroscopy. In addition to the (re-) combination pathway C(3)H(5)+C(3)H(5) → C(6)H(10) we found at low pressures around 1 mbar the highest final product yields for allene and propene for the precursor C(3)H(5)Br. 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. MDPI 2013-11-04 /pmc/articles/PMC6270213/ /pubmed/24192913 http://dx.doi.org/10.3390/molecules181113608 Text en © 2013 by the authors; licensee MDPI, Basel, Switzerland. http://creativecommons.org/licenses/by/3.0/ This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/). |
spellingShingle | Article Seidel, Lars Hoyermann, Karlheinz Mauß, Fabian Nothdurft, Jörg Zeuch, Thomas Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction |
title | Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction |
title_full | Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction |
title_fullStr | Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction |
title_full_unstemmed | Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction |
title_short | Pressure Dependent Product Formation in the Photochemically Initiated Allyl + Allyl Reaction |
title_sort | pressure dependent product formation in the photochemically initiated allyl + allyl reaction |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6270213/ https://www.ncbi.nlm.nih.gov/pubmed/24192913 http://dx.doi.org/10.3390/molecules181113608 |
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