Atmospheric oxidation of furanones by OH and Cl radicals: In situ FTIR rate coefficient determinations, SAR and theoretical studies.

Gas-phase kinetics of the overall reactions of OH and Cl radicals with dihydrofuran-3(2H)-one (oxolan-3-one) and dihydro-2-methyl-3(2H)-furanone (2MTHF-3-one) were studied at 298 K and atmospheric pressure. The rate coefficients were determined using the relative method in a 480 L multipass glass reactor coupled to an FT-IR detection system. The rate coefficients found for oxolan 3-one and 2MTHF-one with OH radicals (k and k) and with Cl atoms (k and k) at 298 K and atmospheric pressure (in cm molecule s) were: k = (1.86 ± 0.29) × 10, k = (2.64 ± 0.47) × 10, k= (1.15 ± 0.28) × 10 , and k = (1.33 ± 0.32) × 10, respectively. Reactivity trends were developed by comparison with other similar structures and Fukui indices employed to determine the reactivity of different sites on the ring. The singularity of the reaction with OH was assessed by computational studies which showed the formation of several stable hydrogen bonded complexes, explaining the difference with the reaction with the Cl atom. SAR estimations of the rate coefficients were calculated and compared to the experimental values.