A New Mechanism for The Atmospheric Oxidation of Dimethyl Sulfide. TheImportance of Intramolecular Hydrogen Shift in CH3SCH2OO Radical
A New Mechanism for The Atmospheric Oxidation of Dimethyl Sulfide. TheImportance of Intramolecular Hydrogen Shift in CH3SCH2OO Radical
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二甲硫醚大气氧化的新机制。
DOI：
10.1021/jp511616j
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
王黎明
中科院分区：
文献类型：
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作者：
Runrun Wu;Sainan Wang;王黎明
对大气中甲硫基甲基过氧自由基(CH3SCH2OO,MSP)的去向进行了理论研究。分子内氢移随后与 O2、MSP→ CH2SCH2OOH → OOCH2SCH2OOH (MSPO2) 重组，被发现足够快，即 293 K 时 2.1 s–1，足以与遥远海洋大气中 MSP 与 NOx、HO2 和 RO2 可能发生的双分子反应竞争甚至超过。MSPO2 还会经历另一次分子内氢移并分解为最重要的中间体HOOCH2SCHO代替了CH3SCH2O自由基。 HOOCH2SCHO进一步氧化的途径为HOOCH2SCO（被OH自由基）→HOOCH2S（被分解）→HOOCH2SO（被O3或NO2）→HOOCH2SO2（被O3和NO2）→OH + CH2O + SO2（被分解）。我们的计算表明，偏远海洋大气中二甲硫醚（CH3SCH3，DMS）的氧化机制截然不同。
Theoretical study has been carried out on the fate of methylthiomethylperoxy radical (CH3SCH2OO,MSP) in the atmosphere. The intramolecular H-shift followed by recombination with O2,MSP→ CH2SCH2OOH → OOCH2SCH2OOH (MSPO2), is found to be fast enough, that is, 2.1 s–1at 293 K, to compete with and even surpass the possible bimolecular reactions ofMSPwith NOx, HO2, and RO2in the remote marine atmosphere.MSPO2would also undergo another intramolecular H-shift and decompose to the most important intermediate HOOCH2SCHO instead of the CH3SCH2O radical. HOOCH2SCHO would be further oxidized via the route as HOOCH2SCO (by OH radical) → HOOCH2S (by decomposition) → HOOCH2SO (by O3or NO2) → HOOCH2SO2(by O3and NO2) → OH + CH2O + SO2(by decomposition). Our calculations suggest a drastically different oxidation mechanism for dimethyl sulfide (CH3SCH3, DMS) in the remote marine atmosphere.