{Atmospheric Fate of Methacrolein. 2. Formation of Lactone and Implications for Organic Aerosol Production}

Citation:

Kjaergaard, HG, et al. “{Atmospheric Fate of Methacrolein. 2. Formation of Lactone and Implications for Organic Aerosol Production}”. J. Phys. Chem. A 116 (2012): , 116, 5763–5768. Web.

Number:

24

ISSN:

1089-5639

Abstract:

We investigate the oxidation of methacryloylperoxy nitrate {(MPAN)} and methacrylicperoxy acid {(MPAA)} by the hydroxyl radical {(OH)} theoretically, using both density functional theory {[B3LYP]} and explicitly correlated coupled cluster theory {[CCSD(T)-F12].} These two compounds are produced following the abstraction of a hydrogen atom from methacrolein {(MACR)} by the {OH} radical. We use a {RRKM} master equation analysis to estimate that the oxidation of {MPAN} leads to formation of hydroxymethyl?methyl-Î$\pm$-lactone {(HMML)} in high yield. {HMML} production follows a low potential energy path from both {MPAN} and {MPAA} following addition of {OH} (via elimination of the {NO3} and {OH} from {MPAN} and {MPAA}, respectively). We suggest that the subsequent heterogeneous phase chemistry of {HMML} may be the route to formation of 2-methylglyceric acid, a common component of organic aerosol produced in the oxidation of methacrolein. Oxidation of acrolein, a photo-oxidation product from 1,3-butadiene, is found to follow a similar route generating hydroxymethyl-Î$\pm$-lactone {(HML).} We investigate the oxidation of methacryloylperoxy nitrate {(MPAN)} and methacrylicperoxy acid {(MPAA)} by the hydroxyl radical {(OH)} theoretically, using both density functional theory {[B3LYP]} and explicitly correlated coupled cluster theory {[CCSD(T)-F12].} These two compounds are produced following the abstraction of a hydrogen atom from methacrolein {(MACR)} by the {OH} radical. We use a {RRKM} master equation analysis to estimate that the oxidation of {MPAN} leads to formation of hydroxymethyl?methyl-Î$\pm$-lactone {(HMML)} in high yield. {HMML} production follows a low potential energy path from both {MPAN} and {MPAA} following addition of {OH} (via elimination of the {NO3} and {OH} from {MPAN} and {MPAA}, respectively). We suggest that the subsequent heterogeneous phase chemistry of {HMML} may be the route to formation of 2-methylglyceric acid, a common component of organic aerosol produced in the oxidation of methacrolein. Oxidation of acrolein, a photo-oxidation product from 1,3-butadiene, is found to follow a similar route generating hydroxymethyl-Î$\pm$-lactone {(HML).}

Website

DOI:

http://pubs.acs.org/doi/abs/10.1021/jp210853h