Wang Xueyu, Sun Jianfei, Bao Lei, Mei Qiong, Wei Bo, An Zexiu, Xie Ju, He Maoxia
Environment Research Institute , Shandong University , Qingdao 266237 , P. R. China.
School of Chemistry and Chemical Engineering , Yangzhou University , Yangzhou 225002 , P. R. China.
J Phys Chem A. 2019 Apr 4;123(13):2745-2755. doi: 10.1021/acs.jpca.8b12025. Epub 2019 Mar 14.
Ozonolysis of unsaturated ketones is a common atmospheric chemical process that plays a significant role in controlling the atmospheric budget of OH and O, organic acids, and secondary organic aerosols (SOA). In this work, the detailed reaction mechanism and rate coefficients for the reactions of O with two unsaturated ketones, 3-methyl-3-buten-2-one (MBO332) and 3-methyl-3-penten-2-one (MPO332), were investigated by using density functional theory (DFT) and Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The results indicate that the major products are butanedione and formaldehyde for MBO332, and butanedione and acetaldehyde for MPO332. Possible reaction mechanism and thermodynamic parameters of some complex stable Criegee intermediates (SCIs) RR'COO were also be investigated in this study. Some organic peroxides can be regarded as the main products for the further reactions of SCIs. The rate constants calculated with O are 2.59 × 10 cm molecule s and 2.28 × 10 cm molecule s for MBO332 and MPO332 at 298 K and 1 atm. The total rate constant is negatively correlated with temperature (200-400 K) and positively correlated with pressure. The atmospheric half-lives of MBO332 and MPO332 based on O are estimated.
不饱和酮的臭氧分解是一种常见的大气化学过程，在控制大气中OH、O、有机酸和二次有机气溶胶（SOA）的含量方面起着重要作用。在这项工作中，利用密度泛函理论（DFT）和莱斯-拉姆齐-卡斯尔-马库斯（RRKM）理论，研究了O与两种不饱和酮3-甲基-3-丁烯-2-酮（MBO332）和3-甲基-3-戊烯-2-酮（MPO332）反应的详细反应机理和速率系数。结果表明，MBO332的主要产物是丁二酮和甲醛，MPO332的主要产物是丁二酮和乙醛。本研究还探讨了一些复杂稳定的克里奇中间体（SCIs）RR'COO的可能反应机理和热力学参数。一些有机过氧化物可被视为SCIs进一步反应的主要产物。在298 K和1 atm条件下，MBO332和MPO332与O反应的速率常数分别计算为2.59×10 cm³·molecule⁻¹·s⁻¹和2.28×10 cm³·molecule⁻¹·s⁻¹。总速率常数与温度（200 - 400 K）呈负相关，与压力呈正相关。估算了基于O的MBO332和MPO332在大气中的半衰期。
