Troposphere reactions of hydroxycyclohexadienyl peroxyl radicals with nitric oxide: A DFT study

The reaction mechanism of nitric oxide with four hydroxycyclohexadienyl peroxyl radicals from the oxidation of benzene in the troposphere has been investigated using the UB3LYP/6-311++G(d,p) density functional theory (DFT) method. The title reaction was found to involve five steps and produce the following intermediates and products: cis-peroxynitrite, trans-peroxynitrite, hydroxycyclohexadienyl nitrate, 2-hydroxy cyclohexadienyl oxyl radical, 3-hydroxy-1,2-epoxy-5-cyclohexene radical (and NO2), hexa-2,4-diene-1,6-dial (trans-HONO), hydroxyl-cyclohexadienone (HNO2). The results confirm that aromatic compounds contribute to tropospheric ozone production, the rain acidity, and secondary organic aerosol (SOA) pollution via the title reaction with a sufficiently high concentration of NOx.