The production of organic nitrates from various anthropogenic volatile organic compounds

Production of organic nitrates from OH reaction with cyclohexane, cyclohexene, n-butane, 1-bromopropane, and p-xylene in the presence of NO was studied. The total organic nitrate yields for cyclohexane and n-butane were determined to be 17 ± 4 and 7 ± 2% respectively, which is in good agreement with previous determinations. Total yields for cyclohexene, 1-bromopropane, and p-xylene were 2.5 ± 0.5, 1.2 ± 0.3, and 3.2 ± 0.7 respectively. The yield for cyclohexene was five times smaller than that for cyclohexane. The 1-bromopropane yield is three times smaller that that for n-propane, but similar to that for propene, indicating that the effect of Br substitution in the reactant may be similar to that for OH substitution. The only nitrooxy product detected for p-xylene was 4-methylbenzylnitrate, which was formed following H abstraction from either methyl group. No organic nitrate was detected for peroxy radicals produced from OH addition to the ring, which accounts for 90% of the OH oxidation of p-xylene. The calculated k _3b/k ₃ value for p-methyl benzyl peroxy radicals (0.32) was slightly smaller than for n-octyl peroxy radicals (0.39). These data imply that substituent inductive effects impact the k _3b/k ₃ ratios. We found no significant difference in the k _3b/k ₃ ratios for primary vs. secondary peroxy radicals of the same carbon chain.