An experimental study of the gas-phase reaction between Cl atoms and trans-2-pentenal: Kinetics, products and SOA formation

• Published in: Chemosphere (Oxford) Vol. 276; p. 130193
• Main Authors: Grira, Asma, Antiñolo, María, Canosa, André, Tomas, Alexandre, Jiménez, Elena, El Dib, Gisèle
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2021; Elsevier
• Subjects: Atmospheric lifetimes; Environmental Sciences; Kinetics; Mechanism; Organic aerosols; Physics; Unsaturated aldehyde; Unsaturated aldehyde; Organic aerosols; Kinetics; Atmospheric lifetimes; Mechanism; Molecular physics; COV
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.130193

The gas-phase reaction of trans-2-pentenal (T2P) with Cl atoms was studied at atmospheric pressure and room temperature. A rate coefficient of (2.56 ± 0.83) × 10-10 cm3 molecule-1 s-1 was obtained using the relative rate method and isoprene, cyclohexane and ethanol as reference compounds. The kinetic study was carried out using a 300-L Teflon bag simulation chamber (IMT Lille Douai-France) and a 16-L Pyrex cell (UCLM-Ciudad Real-Spain), both coupled to the Fourier transform infrared (FTIR) technique. Gas-phase products and secondary organic aerosol (SOA) formation were studied at UCLM using a 16-L Pyrex cell and a 264-L quartz simulation chamber coupled to the FTIR and gas-chromatography-mass spectrometry (GC-MS) techniques. HCl, CO, and propanal were identified as products formed from the studied reaction and quantified by FTIR, the molar yield of the latter being (5.2 ± 0.2)%. Formic acid was identified as a secondary product and was quantified by FTIR with a yield of (6.2 ± 0.4)%. In addition, 2-chlorobutanal and 2–pentenoic acid were identified, but not quantified, by GC-MS as products. The SOA formation was investigated using a fast mobility particle sizer spectrometer. The observed SOA yields reached maximum values of around 7% at high particle mass concentrations. This work provides the first study of the formation of gaseous and particulate products for the reaction of Cl with T2P. A reaction mechanism is suggested to explain the formation of the observed gaseous products. The results are discussed in terms of structure-reactivity relationship, and the atmospheric implications derived from this study are commented as well. •A rate coefficient of (2.56 ± 0.83) × 10−10 cm3 molecule−1 s−1 was obtained for the reaction of T2P with Cl.•This work is the first study of the gas-phase products and the SOA formation from the reaction of T2P with Cl.•The T2P + Cl reaction may contribute to the acidity of marine atmospheres.•The T2P + Cl reaction proceeds mainly by H-abstraction of the aldehydic group and by β-addition of Cl atoms to the double bond.•Atmospheric lifetimes of T2P toward chemical removals are of few hours.