Investigation of the formation of benzoyl peroxide, benzoic anhydride, and other potential aerosol products from gas–phase reactions of benzoylperoxy radicals. (April 2016)

• Record Type: Journal Article
• Authors: Strollo, Christen M.; Ziemann, Paul J.
• Is Part Of: Atmospheric environment. Volume 130(2016)
• Page Start: 202
• Page End: 210
• Publication Date: 2016-04
• Subjects: Secondary organic aerosol -- Volatile organic compounds -- Reaction mechanism -- Oxidation; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2016.01.011
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: The secondary organic aerosol (SOA) products of the reaction of benzaldehyde with Cl atoms and with OH radicals in air in the absence of NOx were investigated in an environmental chamber in order to better understand the possible role of organic peroxy radical self-reactions in SOA formation. SOA products and authentic standards were analyzed using mass spectrometry and liquid chromatography, and results show that the yields of benzoyl peroxide (C6 H5 C(O)OO(O)CC6 H5 ) and benzoic anhydride (C6 H5 C(O)O(O)CC6 H5 ), two potential products from the gas-phase self-reaction of benzoylperoxy radicals (C6 H5 C(O)OO·), were less than 0.1%. This is in contrast to results of recent studies that have shown that the gas-phase self-reactions of β-nitrooxyperoxy radicals formed from reactions of isoprene with NO3 radicals form dialkyl peroxides that contribute significantly to gas-phase and SOA products. Such reactions have also been proposed to explain the gas-phase formation of extremely low volatility dimers from autooxidation of terpenes. The results obtained here indicate that, at least for benzoylperoxy radicals, the self-reactions form only benzoyloxy radicals. Analyses of SOA composition and volatility were inconclusive, but it appears that the SOA may consist primarily of oligomers formed through heterogeneous/multiphase reactions possibly involving some combination of phenol, benzaldehyde, benzoic acid, and peroxybenzoic acid. Highlights: We investigate aerosol formation from reactions of benzaldehyde with Cl atoms and OH radicals. We analyze the aerosol products of the reaction using chromatography and mass spectrometry. We show that the yields of benzoyl peroxide and benzoic anhydride are less than 0.1%. We show that a variety of oligomers are responsible for aerosol formation. We conclude that self-reactions of benzoylperoxy radicals form only benzoyloxy radicals.