Investigation of the gas-phase reactivity of prenol with NO3: kinetics and products

NO 3 radical is a major nocturnal oxidant, therefore it determines the atmospheric lifetime of volatile organic compounds during the night. The reactivity of prenol (an unsaturated alcohol and a potential second-generation biofuel) with NO 3 radicals was investigated in two atmospheric simulation chambers CHARME (CHamber for Atmospheric Reactivity and Metrology of Environment) coupled to PTR-ToF-MS (Proton Transfer Reaction Time of Flight Mass Spectrometry) and THALAMOS (Thermally Regulated Atmospheric Simulation Chamber) coupled to SIFT-MS (Selected Ion Flow Tube Mass Spectrometry). The experiments were performed in the dark, atmospheric pressure, dry conditions (RH < 2 %), and room temperature (293 ± 2 K). The room temperature rate coefficient was determined using the relative rate method leading to an average value of (3.00 ± 0.47) × 10 -12 cm 3 molecule -1 s -1 . This rate coefficient corresponds to a prenol atmospheric lifetime of 28 minutes, indicating that NO 3 oxidation is a major atmospheric removal pathway, faster than degradation by OH radicals (108 minutes) or ozone (72 minutes). In addition, the major gas-phase products were identified to be acetone (20.0 ± 4.0 %) and glycolaldehyde (11.5 ± 1.0 %), while the minor ones were formaldehyde (3.6 ± 0.1 %), prenal (4.2 ± 1.0 %), and 2-methyl-2-nitroxy-propanal (1.6 ± 1.0 %) leading to a carbon mass balance of 22 %. Based on the detected gas-phase products, a detailed chemical reaction mechanism was proposed. The addition mechanism dominates the abstraction pathway leading to the formation of two major products, acetone and glycolaldehyde.