Leibniz-Institut für Troposphärenforschung, TROPOS, 04318 Leipzig (Germany); Department of Physics, P.O. Box 64, 00014 University of Helsinki (Finland).
Angew Chem Int Ed Engl. 2014 Dec 22;53(52):14596-600. doi: 10.1002/anie.201408566. Epub 2014 Oct 29.
Gas-phase oxidation routes of biogenic emissions, mainly isoprene and monoterpenes, in the atmosphere are still the subject of intensive research with special attention being paid to the formation of aerosol constituents. This laboratory study shows that the most abundant monoterpenes (limonene and α-pinene) form highly oxidized RO2 radicals with up to 12 O atoms, along with related closed-shell products, within a few seconds after the initial attack of ozone or OH radicals. The overall process, an intramolecular ROO→QOOH reaction and subsequent O2 addition generating a next R'OO radical, is similar to the well-known autoxidation processes in the liquid phase (QOOH stands for a hydroperoxyalkyl radical). Field measurements show the relevance of this process to atmospheric chemistry. Thus, the well-known reaction principle of autoxidation is also applicable to the atmospheric gas-phase oxidation of hydrocarbons leading to extremely low-volatility products which contribute to organic aerosol mass and hence influence the aerosol-cloud-climate system.
大气中生源排放物（主要是异戊二烯和单萜烯）的气相氧化途径仍然是一个研究热点，特别关注气溶胶成分的形成。本实验室研究表明，最丰富的单萜烯（柠檬烯和α-蒎烯）在初始臭氧或 OH 自由基攻击后几秒钟内，与相关的闭壳产物一起，形成了具有多达 12 个氧原子的高度氧化的 RO2 自由基。整个过程是一个分子内的 ROO→QOOH 反应，随后是 O2 加成生成下一个 R'OO 自由基，类似于液相中众所周知的自动氧化过程（QOOH 代表过氧烷基自由基）。现场测量表明，这一过程与大气化学有关。因此，自动氧化的著名反应原理也适用于烃类在大气气相中的氧化，导致极低挥发性产物，这些产物有助于有机气溶胶质量，从而影响气溶胶-云-气候系统。
