Kinetics and products of the gas-phase reactions of acenaphthylene with hydroxyl radicals, nitrate radicals and ozone

摘要

A series of simulation chamber experiments has been performed on the gas-phase atmospheric oxidation of acenaphthylene with the hydroxyl (OH) radical, ozone (O_3) and the nitrate (NO_3) radical. Using a relative rate technique the following rate coefficients (in cm~3 molecule~(-1) s~(-1)) were determined at (293 ± 3) K in 1 atm of purified air: (1.09 ± 0.07) × 10~(-10), (3.99 ± 0.15) × 10~(-16) and (4.42 ± 0.32) × 10~(-12) for the reactions with OH, O_3 and NO_3 respectively. The results indicate that all three oxidants effectively contribute to the removal of acenaphthylene from the atmosphere. A denuder-filter sampling system coupled with off-line analysis by gas chromatography - mass spectrometry (GC-MS) was used to determine the gas- and particle-phase products of these reactions. The major products identified in the reaction with OH were naphthalene-1,8-dicarbaldehyde, 1,8-naphthaIic anhydride and a 10 carbon ring-opened dialdehyde. The products identified in the reaction with NO_3 and O_3 were predominantly oxygenated compounds arising from reaction at the C=C bond in the cylcopenta-fused ring of acenaphthylene. The formation of hydroxylated and nitro-PAHs appears to be a very minor reaction pathway. Acenaphthenequinone, a compound known to generate reactive oxygen species at the cellular level, was formed from the reactions of acenaphthylene with OH and NO_3. The majority of the oxidation products were found to be distributed between the gas and particle phases, with only acenaphthylenol and oxaacenaphthylen-2-one, relatively more abundant in the particle phase.