第九届青年地学论坛

Organic nitrates (ONs) are considered as important tracers of secondary organic aerosols (SOA) formation and are ubiquitous in the ambient aerosols. However, the mechanistic pathways for the formation of these compounds in the atmosphere are still not well understood. In the present study, we found that ONs can form from the multiphase reactions of organic peroxides (i.e., tert-butyl peroxide, 2-butanone peroxide, and cumene hydroperoxide) with nitrite anion (NO₂^–). The mechanism for ONs formation involves the recombination of [RO• •NO₂] caged radical pair resulted from the homolysis cleavage of ROONO, which is the intermediate during the reaction. As shown here, the yield of ONs is slightly affected by the value of organic peroxides/ NO₂^– ratio, organic peroxide structure and solution pH, while the second order rate constant closely depends on the solution pH and organic peroxide structure. Extrapolating the kinetic and mechanism results to the real atmosphere shows that this novel pathway of nitrite-organic peroxides reaction is important for ONs formation in aerosol under typical continental atmospheric conditions.
 

亚硝酸,有机过氧化物,有机硝酸酯