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首页> 外文期刊>Environmental Science & Technology >Kinetics of the Reactions of Isoprene-Derived Epoxides in Model Tropospheric Aerosol Solutions
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Kinetics of the Reactions of Isoprene-Derived Epoxides in Model Tropospheric Aerosol Solutions

机译：对流层气溶胶溶液中异戊二烯衍生的环氧化合物的反应动力学

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摘要

Polyols and organic sulfates have recently been identified in the secondary organic aerosol (SOA)formed in the photooxidation of isoprene in both the laboratory and under ambient atmospheric conditions. Nuclear magnetic resonance methods were used to monitor the bulk reaction kinetics of acid-catalyzed hydrolysis reactions for isoprene- and 1,3-butadiene-derived epoxides in order to determine the rates for such reactions in aerosols under the previously studied laboratory conditions and under ambient atmospheric conditions. The measured rate constants were found to vary over 7 orders of magnitude. For the fast case of the hydrolysis of 1,2-epoxyisoprene, the lifetime at neutral pH was found to be only 3 min. On the other hand, for the relatively slow reaction of 1,2-epoxy-3,4-hydroxybutane,the lifetime atthe mostacidic conditions commonly observed in tropospheric aerosols (pH 1.5) was found to be 7.7 h, a value that is still less than the several day lifetime of tropospheric aerosols. Therefore, the present results suggest that, despite a wide range in reactivities, several possible reactions of isoprene-derived epoxides should be kinetically efficient on atmospheric SOA. The reactions were also studied with the elevated sulfate concentrations that are often characteristic of tropospheric aerosols, and sulfate products were identified for all species except 1,2-epoxyisoprene. Other nucleophiles that may be present in aerosols (nitrate, chloride, bromide, and iodide) were also investigated, and it was found that nitrate and sulfate have similar nucleophilic strength, while the halides are much stronger nucleophiles in their reactions with epoxides. Therefore, aerosols which contain significant concentrations of these species may be expected to readily form species similarto those already identified for the reactions of epoxides with sulfate.
机译：最近，在实验室和环境大气条件下，异戊二烯的光氧化形成的次级有机气溶胶（SOA）中都发现了多元醇和有机硫酸盐。核磁共振方法用于监测异戊二烯和1,3-丁二烯衍生的环氧化物的酸催化水解反应的整体反应动力学，以便确定在先前研究的实验室条件和环境下在气溶胶中此类反应的速率大气条件。发现测得的速率常数变化超过7个数量级。对于1,2-环氧异戊二烯水解的快速情况，发现在中性pH下的寿命仅为3分钟。另一方面，对于1,2-环氧-3,4-羟基丁烷的反应相对较慢，发现在对流层气溶胶（pH 1.5）中最常观察到的最酸性条件下的寿命为7.7 h，该值仍然较小比对流层气溶胶的几天寿命。因此，目前的结果表明，尽管反应性范围很广，异戊二烯衍生的环氧化物的几种可能的反应在大气SOA上应是动力学有效的。还用通常是对流层气溶胶特征的升高的硫酸盐浓度研究了反应，并鉴定了除1,2-环氧异戊二烯外的所有物种的硫酸盐产物。还研究了气溶胶中可能存在的其他亲核试剂（硝酸盐，氯化物，溴化物和碘化物），并且发现硝酸盐和硫酸盐具有相似的亲核强度，而卤化物在与环氧化物的反应中是更强的亲核试剂。因此，可以预期，包含这些物质的高浓度的气雾剂容易形成类似于已经针对环氧化物与硫酸盐的反应鉴定的那些的物质。

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  • 来源
    《Environmental Science & Technology》 |2009年第21期|8133-8139|共7页
  • 作者

    EMILY C. MINERATH; MADELINE P. SCHULTZ; MATTHEW J. ELROD;

  • 作者单位

    Department of Chemistry and Biochemistry, 119 Woodland Street, Oberlin College, Oberlin, Ohio 44074;

    Department of Chemistry and Biochemistry, 119 Woodland Street, Oberlin College, Oberlin, Ohio 44074;

    Department of Chemistry and Biochemistry, 119 Woodland Street, Oberlin College, Oberlin, Ohio 44074;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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