Water Dramatically Accelerates the Decomposition of α-Hydroxyalkyl-Hydroperoxides in Aerosol Particles
Water Dramatically Accelerates the Decomposition of α-Hydroxyalkyl-Hydroperoxides in Aerosol Particles
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DOI：
10.1021/acs.jpclett.9b01953
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发表时间：
2019-09
期刊：
影响因子：
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通讯作者：
Junting Qiu;Shinnosuke Ishizuka;K. Tonokura;A. Colussi;Shinichi Enami
中科院分区：
文献类型：
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作者：
Junting Qiu;Shinnosuke Ishizuka;K. Tonokura;A. Colussi;Shinichi Enami
α-羟烷基氢过氧化物（α-HHs）是有机气溶胶中的活性组分，是烯烃臭氧分解反应中Criegee中间体与水反应生成的产物。要评估α-六六六在这种介质中的归宿，需要了解它们在含水有机基质中反应的速率和产物。然而，由于缺乏检测和鉴定不稳定α-六六六的分析技术，无法获得这一信息。本文报道了C15二烯烃在含有惰性NaCl的水（W）：乙腈（AN）混合物中臭氧分解产生的α-HH的质谱检测（作为Cl-加合物）。α-HH在50%（v：v）水中在τ1/e ≤ 52 min内衰变为偕二醇+H2 O2，但在≤10%的水混合物中持续时间超过1天。τ1/e与溶剂组成的强非线性关系表明，大气颗粒物中水含量是控制α-HHs归宿的主要因素。它还表明，α-HH分解，而嵌入在WnANm簇，而不是随机溶解在分子均匀的W：AN混合物。
α-Hydroxyalkyl-hydroperoxides (α-HHs), from the addition of water to Criegee intermediates in the ozonolysis of olefins, are reactive components of organic aerosols. Assessing the fate of α-HHs in such media requires information on the rates and products of their reactions in aqueous organic matrixes. This information, however, is unavailable due to the lack of analytical techniques for the detection and identification of labile α-HHs. Here, we report the mass spectrometric detection (as Cl– adducts) of the α-HH produced in the ozonolysis of a C15 diolefin in water (W):acetonitrile (AN) mixtures of variable composition containing inert NaCl. α-HH decays into a gem-diol + H2O2 within τ1/e ≈ 52 min in 50% (v:v) water, but persists longer than a day in ≤10% water mixtures. The strong nonlinear dependence of τ1/e on solvent composition reveals that water content is a major factor controlling the fate of α-HHs in atmospheric particles. It also suggests that α-HH decomposes while embedded in WnANm clusters rather than randomly dissolved in molecularly homogeneous W:AN mixtures.