Unimolecular reaction chemistry of a charge-tagged beta-hydroxyperoxyl radical


Autoria(s): So, Sui; Kirk, Benjamin; Trevitt, Adam; Wille, Uta; Blanksby, Stephen; da Silva, Gabriel
Data(s)

2014

Resumo

β-Hydroxyperoxyl radicals are formed during atmospheric oxidation of unsaturated volatile organic compounds such as isoprene. They are intermediates in the combustion of alcohols. In these environments the unimolecular isomerization and decomposition of β-hydroxyperoxyl radicals may be of importance, either through chemical or thermal activation. We have used ion-trap mass spectrometry to generate the distonic charge-tagged β-hydroxyalkyl radical anion, ˙CH2C(OH)(CH3)CH2C(O)O−, and investigated its subsequent reaction with O2 in the gas phase under conditions that are devoid of complicating radical–radical reactions. Quantum chemical calculations and master equation/RRKM theory modeling are used to rationalize the results and discern a reaction mechanism. Reaction is found to proceed via initial hydrogen abstraction from the γ-methylene group and from the β-hydroxyl group, with both reaction channels eventually forming isobaric product ions due to loss of either ˙OH + HCHO or ˙OH + CO2. Isotope labeling studies confirm that a 1,5-hydrogen shift from the β-hydroxyl functionality results in a hydroperoxyalkoxyl radical intermediate that can undergo further unimolecular dissociations. Furthermore, this study confirms that the facile decomposition of β-hydroxyperoxyl radicals can yield ˙OH in the gas phase.

Identificador

http://eprints.qut.edu.au/88691/

Publicador

RSC Publications

Relação

DOI:10.1039/C4CP02981J

So, Sui, Kirk, Benjamin, Trevitt, Adam, Wille, Uta, Blanksby, Stephen, & da Silva, Gabriel (2014) Unimolecular reaction chemistry of a charge-tagged beta-hydroxyperoxyl radical. Physical Chemistry Chemical Physics, 16(45), pp. 24954-24964.

http://purl.org/au-research/grants/ARC/DP110103889

http://purl.org/au-research/grants/ARC/DP140101237

http://purl.org/au-research/grants/ARC/DP130100862

Direitos

Copyright 2014 the Owner Societies

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence

Fonte

School of Chemistry, Physics & Mechanical Engineering; Science & Engineering Faculty

Tipo

Journal Article