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

Abstract

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 (k1 and k2) and with •Cl atoms (k3 and k4) at 298 K and atmospheric pressure (in cm3 molecule−1 s−1) were: k1 = (1.86 ± 0.29) × 10−11, k2 = (2.64 ± 0.47) × 10−11, k3= (1.15 ± 0.28) × 10 −10, and k4 = (1.33 ± 0.32) × 10−10, 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.