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

摘要

A series of simulation chamber experiments has been performed on the atmospheric oxidation of acenaphthene at (293 ± 3) K in 1 atm of purified air. Rate coefficients for reaction with hydroxyl (OH) radicals, nitrate (NO_3) radicals and ozone have been determined using the relative rate technique. The values obtained for reaction with OH and O_3 were (in units of cm~3 molecule~(-1) s~(-1)) (9.89 ± 0.51) × 10~(-11) and (1.79 ± 0.10) × 10~(-19) respectively. The rate coefficient for reaction with NO3 was found to be dependent on NO_2 concentration and is given by (4.16 ± 0.70) × 10~(-13) + (3.45 ± 1.73) × 10~(-27)[NO_2] cm~3 molecule~(-1) s~(-1). A denuder-filter sampling system coupled with off-line GC-MS analysis was used to collect and identify gas- and particle-phase products of the OH and NO_3 initiated oxidation of acenaphthene. For the OH reaction, a range of ring-retaining and ring-opening products were identified in both phases, although some species, including nitroacenaphthene and 1,8-naphthalic anhydride, were found exclusively in the particle phase. In particular, the identification of 1-acenaphthenone and naphthalene-l,8-dicarbaldehyde amongst the products indicates that H-atom abstraction from the cyclopenta-fused ring is an important reaction pathway, along with OH addition to the aromatic ring. For the NO_3 reaction, 1-acenaphthenone and nitroacenaphthene were identified as the major gas- and particle-phase products respectively. Possible reaction mechanisms for the formation of these products are proposed.