Rate Coefficients for the Gas-Phase Reactions of Nitrate Radicals with a Series of Furan Compounds

The atmospheric reaction of a series of furan compounds (furan (F), 2-methylfuran (2-MF), 3-methylfuran (3-MF), 2,5-dimethylfuran (2,5-DMF), and 2,3,5-trimethylfuran (2,3,5-TMF)) with nitrate radical (NO₃) has been investigated using the relative rate kinetic method in the CHamber for the Atmospheric Reactivity and the Metrology of the Environment (CHARME) simulation chamber at the laboratoire de Physico-Chimie de l'Atmosphere (LPCA) laboratory (Dunkerque, France). The experiments were performed at (294 ± 2) K atmospheric pressure and under dry conditions (relative humidity, RH < 2%) with proton transfer mass reaction-time of flight-mass spectrometer (PTR-ToF-MS) for the chemical analysis. The following rate coefficients (in units cm³ molecule^-1 s^-1) were determined: furan, k_(F) = (1.51 ± 0.38) × 10^-12, 2-methylfuran, k_(2-MF) = (1.91 ± 0.32) × 10^-11, 3-methylfuran, k_(3-MF) = (1.49 ± 0.33) × 10^-11, 2,5-dimethylfuran, k_(2,5-DMF) = (5.82 ± 1.21) × 10^-11, and 2,3,5-trimethylfuran, k_(2,3,5-TMF) = (1.66 ± 0.69) × 10^-10. The uncertainty on the measured rate coefficient (Δk_FC) includes both the uncertainty on the measurement and that on the rate coefficient of the reference molecule. To our knowledge, this work represents the first determination for the rate coefficient of the 2,3,5-TMF reaction with NO₃. This work shows that the reaction between furan and methylated furan compounds with nitrate radical (NO₃) is the dominant removal pathway during the night with lifetimes between 0.5 and 55 min for the studied molecules.