Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
J Phys Chem A. 2012 Jun 21;116(24):5763-8. doi: 10.1021/jp210853h. Epub 2012 May 16.
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-α-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 NO(3) 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-α-lactone (HML).
我们通过密度泛函理论[B3LYP]和显式相关耦合簇理论[CCSD(T)-F12]理论上研究了甲基丙烯酰过氧硝酸盐（MPAN）和甲基丙烯酰过氧酸（MPAA）的氧化反应，这两种化合物是由羟基自由基（OH）从甲基丙烯醛（MACR）中提取氢原子产生的。我们使用 RRKM 主方程分析来估计 MPAN 的氧化导致羟甲基-甲基-α-内酯（HMML）的高产率形成。HMML 的产生遵循从 MPAN 和 MPAA 到 OH 的加成的低势能路径（通过分别从 MPAN 和 MPAA 中消除 NO(3)和 OH）。我们认为 HMML 的随后的多相相化学可能是形成 2-甲基甘油酸的途径，2-甲基甘油酸是 1,3-丁二烯光氧化产物中有机气溶胶形成的常见成分。丙烯醛的氧化，一种来自 1,3-丁二烯的光氧化产物，被发现遵循类似的生成羟甲基-α-内酯（HML）的途径。
