Atmospheric Chemistry Department (ACD), Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße 15, Leipzig 04318, Germany.
Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark.
J Phys Chem A. 2021 May 27;125(20):4454-4466. doi: 10.1021/acs.jpca.1c02465. Epub 2021 May 12.
Autoxidation in the atmosphere has been realized in the last decade as an important process that forms highly oxidized products relevant for the formation of secondary organic aerosol and likely with detrimental human health effects. It is experimentally shown that the OH radical-initiated oxidation of trimethylamine, the most highly emitted amine in the atmosphere, proceeds via rapid autoxidation steps dominating its atmospheric oxidation process. All three methyl groups are functionalized within a timescale of 10 s following the reaction with OH radicals leading to highly oxidized products. The exceptionally large density of functional groups in the oxidized products is expected to define their chemical properties. A detailed reaction mechanism based on theoretical calculations is able to describe the experimental findings. The comparison with results of the reinvestigated OH radical- and ozone-initiated autoxidation of a series of terpenes and aromatics reveals the trimethylamine process as the most efficient one discovered up to now for atmospheric conditions.
在过去的十年中，人们已经认识到大气中的自动氧化是一个重要的过程，它形成了与二次有机气溶胶形成有关的高度氧化产物，并且可能对人类健康产生不利影响。实验表明，大气中排放最多的胺——三甲胺在 OH 自由基引发的氧化过程中，通过快速的自动氧化步骤进行，这些步骤主导着其大气氧化过程。在与 OH 自由基反应 10 秒内，所有三个甲基都被功能化，导致生成高度氧化的产物。在氧化产物中，异常大量的功能基团预计将决定它们的化学性质。一个基于理论计算的详细反应机制能够描述实验结果。与重新研究的一系列萜烯和芳烃的 OH 自由基和臭氧引发的自动氧化的结果进行比较表明，对于大气条件而言，三甲胺过程是迄今为止发现的最有效的过程。
