Reaction Kinetics and Secondary Organic Aerosol Composition Analysis of 2-Cyclohexen-1-one with NO₃ Radicals

Unsaturated ketones are typical oxygenated volatile organic compounds (OVOCs) with high reactivity, and are important precursors in air pollution. The sources of OVOCs are complex and include direct emissions and secondary oxidation formation of VOCs in the atmosphere. 2-Cyclohexen-1-one is a widespread substance, and is derived from the industrial catalytic oxidation of cyclohexene. In this paper, we investigated the rate constants of the chemical reactions of 2-cyclohexen-1-one with NO₃ radicals, which is (7.25±0.29)×10⁻¹⁵ cm³·molecule⁻¹·s⁻¹ at 298 K and under 1 atm (1 atm=101325Pa). It supplemented the kinetics of NO₃ radicals database, and revealed its effects in the nighttime atmosphere. In addition, the reaction products of 2-cyclohexen-1-one with NO₃ radicals were detected by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), which revealed a series of nitrate esters in the composition of the secondary organic aerosol (SOA), which may reduce atmospheric visibility. Finally, the possible pathways for the generation of the products were developed.