当前位置: X-MOL 学术ACS Earth Space Chem. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Organosulfates from Dark Aqueous Reactions of Isoprene-Derived Epoxydiols Under Cloud and Fog Conditions: Kinetics, Mechanism, and Effect of Reaction Environment on Regioselectivity of Sulfate Addition
ACS Earth and Space Chemistry ( IF 2.9 ) Pub Date : 2021-02-16 , DOI: 10.1021/acsearthspacechem.0c00293
Sarah S. Petters 1 , Tianqu Cui 1 , Zhenfa Zhang 1 , Avram Gold 1 , V. Faye McNeill 2 , Jason D. Surratt 1, 3 , Barbara J. Turpin 1
Affiliation  

Atmospheric oxidation of isoprene yields large quantities of highly water-soluble isoprene epoxydiols (IEPOX) that partition into fogs, clouds, and wet aerosols. In aqueous aerosols, the acid-catalyzed ring-opening of IEPOX followed by nucleophilic addition of inorganic sulfate or water forms organosulfates and 2-methyltetrols, respectively, contributing substantially to secondary organic aerosol (SOA). However, the fate of IEPOX in clouds, fogs, and evaporating hydrometeors is not well understood. Here we investigate the rates, product branching ratios, and stereochemistry of organosulfates from reactions of dilute IEPOX (5–10 mM) under a range of sulfate concentrations (0.3–50 mM) and pH values (1.83–3.38) in order to better understand the fate of IEPOX in clouds and fogs. From these aqueous dark reactions of β-IEPOX isomers (trans- and cis-2-methyl-2,3-epoxybutane-1,4-diols), which are the predominant IEPOX isomers, products were identified and quantified using hydrophilic interaction liquid chromatography coupled to an electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in negative ion mode (HILIC/(−)ESI-HR-QTOFMS). We found that the regiochemistry and stereochemistry were affected by pH, and the tertiary methyltetrol sulfate (C5H12O7S) was promoted by increasing solution acidity. Furthermore, the rate constants for the reaction of IEPOX under cloud-relevant conditions are up to 1 order of magnitude lower than reported in the literature for aerosol-relevant conditions due to a markedly different solution activities. Nevertheless, the contribution of cloud and fog water reactions to IEPOX SOA may be significant in cases of lower aqueous-phase pH (model estimate) or during droplet evaporation (not studied).

中文翻译:

云和雾条件下异戊二烯衍生的环氧二醇的暗水反应中的有机硫酸盐:动力学,机理和反应环境对硫酸加成区域选择性的影响

异戊二烯在大气中的氧化会产生大量高度水溶性的异戊二烯环氧二醇(IEPOX),可分为雾,云和湿气溶胶。在水性气雾剂中,IEPOX的酸催化开环反应,然后以亲核方式加入无机硫酸盐或水,分别形成有机硫酸盐和2-甲基四醇,从而大大促进了次级有机气雾剂(SOA)。但是,人们对IEPOX在云,雾和蒸发的水凝物中的命运还知之甚少。在这里,我们研究了在一定范围的硫酸盐浓度(0.3–50 mM)和pH值(1.83–3.38)下稀薄的IEPOX(5–10 mM)反应中有机硫酸盐的速率,产物支化比和立体化学,以便更好地理解IEPOX在云雾中的命运。来自这些β-IEPOX异构体的水性暗反应(反式-和顺式-2-甲基- 2,3-环氧丁烷-1,4-二醇),其是主要的异构体IEPOX,产物识别和量化使用耦合到电喷雾电离高分辨率四极时间亲水性相互作用液相色谱飞行质谱仪以负离子模式运行(HILIC /(-)ESI-HR-QTOFMS)。我们发现,区域化学和立体化学会受到pH值的影响,而叔甲基硫酸四叔甲基酯(C 5 H 12 O 7通过增加溶液的酸度来促进S)。此外,由于溶液活性显着不同,与云有关的条件下,IEPOX反应的速率常数比与气溶胶有关的条件下文献报道的速率常数低多达一个数量级。但是,在水相pH较低(模型估计)或液滴蒸发(未研究)的情况下,云水和雾水反应对IEPOX SOA的贡献可能很大。
更新日期:2021-03-18
down
wechat
bug