Organosulfate and Nitrate Formation and Reactivity from Epoxides Derived from 2-Methyl-3-buten-2-ol

Abstract

Recent work has suggested that 2-methyl-3-butene-2-ol (MBO)-derived epoxide intermediates are responsible for some of the molecular species commonly found in ambient secondary organic aerosol (SOA). Nuclear magnetic resonance techniques were used to study the reaction kinetics and products of two potential MBO-derived epoxides under acidic solution conditions in the presence of sulfate and nitrate nucleophiles. These epoxides were found to undergo reasonably fast acid-catalyzed reaction at typical SOA acidities and to produce a variety of organosulfate and nitrate species. This finding supports a previous supposition that 3-methylbutane-1,2,3-triol and at least some of the MBO-derived organosulfates previously detected on SOA are formed from the reactions of these epoxides. In general, the particular MBO-derived organosulfates and nitrates produced from MBO-derived epoxides and their respective stability toward hydrolysis were similar to those found for isoprene-derived epoxides; the nucleophilic reactions were observed to be quite regiospecific, and the tertiary addition product species were found to hydrolyze on atmospherically relevant time scales.

Chemical characterization of organosulfates in secondary organic aerosol derived from the photooxidation of alkanes

“…Although the variety of OSs identified from field measurements is quite large (Surratt et al, 2008;Tao et al, 2014;Wang et al, 2015;Kuang et al, 2016), only a few OS precursors have been unequivocally identified through laboratory studies. OSs have been generated in SOA in smog chambers from OH, NO 3 or O 3 oxidation of biogenic VOCs (BVOCs), including isoprene (Surratt et al, 2007;Ng et al, 2008), 2methyl-3-buten-2-ol (MBO) (Zhang et al, 2012;Mael et al, 2015), unsaturated aldehydes (Schindelka et al, 2013;Shalamzari et al, 2014Shalamzari et al, , 2015, monoterpenes (Iinuma et al, 2007(Iinuma et al, , 2009Surratt et al, 2008) and sesquiterpenes (Liggio et al, 2006;Surratt et al, 2008;Iinuma et al, 2009;Noziere et al, 2010;Chan et al, 2011) in the presence of acidified sulfate aerosol. However, the large number of unidentified OSs with C 2 -C 25 skeletons observed in recent field studies is clearly not derived from BVOC precursors and suggests alkanes and aromatics as a major source of hitherto unrecognized of OS precursors (Tao et al, 2014;Wang et al, 2015;Kuang et al, 2016).…”

Photooxidation of cyclohexene in the presence of SO<sub>2</sub>: SOA yield and chemical composition

“…The authors further found that organonitrates could easily be transformed to organosulfates during hydrolysis in the presence of sulfate. Some studies also showed that 2-methyl-3-buten-2-ol (MBO), due to its emissions that are larger than isoprene in some regions (Baker et al, 1999), is an important precursor for organosulfates and SOA in the atmosphere through its reactions with OH under NO and aerosol acidity conditions and from acid-catalysed reactive uptake of MBO-based epoxides formed during MBO photooxidation (Mael et al, 2015;Zhang et al, 2012Zhang et al, , 2014. Organosulfate formation was also found from oxidation of hydroxyhydroperoxides (Riva et al, 2016) and from heterogeneous reactions of SO 2 with selected long-chain alkenes and unsaturated fatty acids (Passananti et al, 2016).…”

Reply to Reviewer 1

“…The structure proposed for OS-285 is based on the formation of reaction of the hydroperoxy peroxyl radical intermediate in pathway b with RO 2 followed by a 1,4-H shift and addition of O 2 to give a hydroxyhydroperoxyperoxyl radical (C 9 H 17 O q 5 ). C 9 H 17 O q 5 could then lead to an epoxide by isomerization Sur-ratt et al, 2010;Jacobs et al, 2013;Mael et al, 2015) and form OS-285. C 9 H 17 O q 5 could also react with HO 2 and form the corresponding C 9 -hydroxydihydroperoxide (C 9 H 18 O 5 ), which could then undergo heterogeneous reaction and lead to OS-269 ( Fig.…”

“…Although the variety of OSs identified from field measurements is quite large Tao et al, 2014;Wang et al, 2015;Kuang et al, 2016), only a few OS precursors have been unequivocally identified through laboratory studies. OSs have been generated in SOA in smog chambers from OH, NO 3 or O 3 oxidation of biogenic VOCs (BVOCs), including isoprene (Surratt et al, 2007;Ng et al, 2008), 2methyl-3-buten-2-ol (MBO) (Zhang et al, 2012;Mael et al, 2015), unsaturated aldehydes (Schindelka et al, 2013;Shalamzari et al, 2014Shalamzari et al, , 2015, monoterpenes (Iinuma et al, 2007Surratt et al, 2008) and sesquiterpenes (Liggio et al, 2006;Surratt et al, 2008;Iinuma et al, 2009;Noziere et al, 2010;Chan et al, 2011) in the presence of acidified sulfate aerosol. However, the large number of unidentified OSs with C 2 -C 25 skeletons observed in recent field studies is clearly not derived from BVOC precursors and suggests alkanes and aromatics as a major source of hitherto unrecognized of OS precursors (Tao et al, 2014;Wang et al, 2015;Kuang et al, 2016).…”