Criegee Intermediates React with Levoglucosan on Water
Criegee Intermediates React with Levoglucosan on Water
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DOI：
10.1021/acs.jpclett.7b01665
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发表时间：
2017-08-17
影响因子：
5.7
通讯作者：
Colussi, A. J.
中科院分区：
文献类型：
--
作者：
Enami, Shinichi;Hoffmann, Michael R.;Colussi, A. J.
左旋葡聚糖 (Levo) 是纤维素材料燃烧中产生的一种 C-6-脱水糖，是全球广大地区生物质燃烧产生的气溶胶的主要成分。 Levo 长期以来被认为具有化学惰性，因此一直被用作生物质燃烧源的示踪剂。然而，我们现在表明，包括Levo、葡萄糖、阿拉伯糖醇和甘露醇在内的糖类与倍半萜烯在水：乙腈微射流表面上臭氧分解过程中产生的Criegee中间体（CI）快速反应。在空气-水界面上，亲水性 Levo 与 CI 的反应速度比与水或表面活性 1-辛醇的反应速度更快。这种意想不到的现象可能与空气-水界面处相对较低的水OH密度以及糖羟基（即-OH）相对于正烷醇较高的气相酸度有关。本文提供的结果表明，气溶胶糖实际上对 CI 具有反应性。鉴于大气中糖类含量丰富，它们可能是二次有机气溶胶生长和质量负荷的重要贡献者。
Levoglucosan (Levo), a C-6-anhydrosaccharide produced in the combustion of cellulosic materials, is the major component of aerosols produced from biomass burning over vast regions worldwide. Levo has long been considered chemically inert and thus has been used as a tracer of biomass burning sources. However, we now show that sugars including Levo, glucose, arabitol, and mannitol react rapidly with Criegee intermediates (CIs) generated during the ozonolysis of sesquiterpenes on the surface of water:acetonitrile microjets. Hydrophilic Levo reacts faster with CIs than with water or surface-active 1-octanol at air aqueous interfaces. This unexpected phenomenon is likely associated with the relatively low water OH density at air aqueous interfaces coupled with a higher gas-phase acidity of the saccharide hydroxyl groups (i.e., -OH) versus n-alkanols. Results presented herein show that aerosol saccharides are in fact reactive toward CIs. Given the abundance of saccharides in the atmosphere, they may be important contributors to the growth and mass loading of secondary organic aerosols.