This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).
Estimation of rate coefficients and branching ratios for reactions of
organic peroxy radicals for use in automated mechanism
construction
Michael E. Jenkin1,2,Richard Valorso3,Bernard Aumont3,and Andrew R. Rickard4,5Michael E. Jenkin et al. Michael E. Jenkin1,2,Richard Valorso3,Bernard Aumont3,and Andrew R. Rickard4,5
1Atmospheric Chemistry Services, Okehampton, Devon, EX20 4QB, UK
2School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, UK
3LISA, UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot, Institut Pierre Simon Laplace, 94010 Créteil, France
4Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, UK
5National Centre for Atmospheric Science, University of York, York, YO10 5DD, UK
1Atmospheric Chemistry Services, Okehampton, Devon, EX20 4QB, UK
2School of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, UK
3LISA, UMR CNRS 7583, Université Paris Est Créteil et Université Paris Diderot, Institut Pierre Simon Laplace, 94010 Créteil, France
4Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, YO10 5DD, UK
5National Centre for Atmospheric Science, University of York, York, YO10 5DD, UK
Received: 18 Jan 2019 – Accepted for review: 04 Feb 2019 – Discussion started: 05 Feb 2019
Abstract. Organic peroxy radicals (RO2), formed from the degradation of hydrocarbons and other volatile organic compounds (VOCs), play a key role in tropospheric oxidation mechanisms. Several competing reactions may be available for a given RO2 radical, the relative rates of which depend on both the structure of RO2 and the ambient conditions. Published kinetics and branching ratio data are reviewed for the bimolecular reactions of RO2 with NO, NO2, NO3, OH and HO2; and for their self-reactions and cross-reactions with other RO2 radicals. This information is used to define generic rate coefficients and structure-activity relationship (SAR) methods that can be applied to the bimolecular reactions of a series of important classes of hydrocarbon and oxygenated RO2 radical. Information for selected unimolecular isomerization reactions (i.e. H-atom shift and ring-closure reactions) is also summarised and discussed. The methods presented here are intended to guide the representation of RO2 radical chemistry in the next generation of explicit detailed chemical mechanisms.
Organic compounds are emitted in large amounts from natural and human-influenced sources. Peroxy radicals are key intermediates formed during oxidation of organic compounds, and play a central role in mechanisms forming pollutants such as ozone and organic particles. Due to the large number of different peroxy radicals formed, it is impossible to study the rates of all of their reactions, and most have to be estimated. Updated and new estimation methods are reported for use in atmospheric models.
Organic compounds are emitted in large amounts from natural and human-influenced sources. Peroxy...