Kinetic and product studies of the reactions of NO3 with a series of unsaturated organic compounds.
J Environ Sci (China)
; 95: 111-120, 2020 Sep.
Article
em En
| MEDLINE
| ID: mdl-32653170
ABSTRACT
Rate coefficients for the reaction of NO3 radicals with 6 unsaturated volatile organic compounds (VOCs) in a 7300 L simulation chamber at ambient temperature and pressure have been determined by the relative rate method. The resulting rate coefficients were determined for isoprene, 2-carene, 3-carene, methyl vinyl ketone (MVK), methacrolein (MACR) and crotonaldehyde (CA), as (6.6 ± 0.8) × 10-13, (1.8 ± 0.6) × 10-11, (8.7 ± 0.5) × 10-12, (1.24 ± 1.04) × 10-16, (3.3 ± 0.9) × 10-15 and (5.7 ± 1.2) × 10-15 cm3/(moleculeâ¢sec), respectively. The experiments indicate that NO3 radical reactions with all the studied unsaturated VOCs proceed through addition to the olefinic bond, however, it indicates that the introduction of a carbonyl group into unsaturated VOCs can deactivate the neighboring olefinic bond towards reaction with the NO3 radical, which is to be expected since the presence of these electron-withdrawing substituents will reduce the electron density in the π orbitals of the alkenes, and will therefore reduce the rate coefficient of these electrophilic addition reactions. In addition, we investigated the product formation from the reactions of 2-carene and 3-carene with the NO3 radical. Qualitative identification of an epoxide (C10H16OH+), caronaldehyde (C10H16O2H+) and nitrooxy-ketone (C10H16O4NH+) was achieved using a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) and a reaction mechanism is proposed.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluentes Atmosféricos
/
Compostos Orgânicos Voláteis
Tipo de estudo:
Qualitative_research
Idioma:
En
Revista:
J Environ Sci (China)
Assunto da revista:
SAUDE AMBIENTAL
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
França