Nitrogen-containing secondary organic aerosol formation by acrolein reaction with ammonia/ammonium

摘要: Abstract. Ammonia-driven carbonyl-to-imine conversion is an important formation pathway to the nitrogen-containing organic compounds (NOCs) in secondary aerosols (SOAs). Previous studies have mainly focused on the dicarbonyl as precursors of light-absorbing NOCs. In this work, we investigated whether acrolein could also act NOC precursor. Acrolein is simplest α , β -unsaturated mono-carbonyl compound, and it is ubiquitous in atmosphere. Experiments probing multiphase reactions of acrolein well bulk aqueous-phase experiments were carried out study the reactivity towards ammonia ammonium ions. Molecular characterization products based gas chromatography mass spectrometry, high-resolution mass spectrometry, surface-enhanced Raman spectrometry ultraviolet/visible spectrophotometry was used propose possible reaction mechanisms. We observed 3-methylpyridine (commonly known 3-picoline) phase in Tedlar bags filled with gaseous or ammonium aerosols. ammonium-containing aqueous phase, oligomeric with formulas ( C3H4O ) m C3H5N n pyridinium compounds like 2 C6H8N+ the products. The proposed be the intramolecular carbon–carbon addition hemiaminal, which resulted from sequential conversions molecules. The 3-methylpyridine formed but some the 3-methylpyridine revolatilize explaining the observation bags. The ( a carbonyl-to-hemiaminal product from dimer 3-methylpyridine, while of ( polymers acroleins and propylene imines via condensation reactions. pH value effect liquid studied the bulk experiments. While forming in both acidic alkaline conditions, pyridinium favored moderately conditions. Both pyridinium salts are materials. This work suggests that may serve precursor heterocyclic NOCs SOA. Therefore, secondary aldehydes reduced nitrogen should taken into account source in SOA.