Comprehensive Analysis of Products and the Development of a Quantitative Mechanism for the OH Radical-Initiated Oxidation of 1-Alkenes in the Presence of NO x
Comprehensive Analysis of Products and the Development of a Quantitative Mechanism for the OH Radical-Initiated Oxidation of 1-Alkenes in the Presence of NO x
复制标题
NO x 存在下 OH 自由基引发的 1-烯烃氧化的产物综合分析和定量机制的开发
DOI：
10.1021/acs.jpca.1c03688
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Ziemann, Paul J.
中科院分区：
文献类型：
--
作者：
Bakker-Arkema, Julia G.;Ziemann, Paul J.
通过一系列环境实验研究了1-十四烯和1-十五烯（c14和c15线性1-烯烃）在nox存在下与OH自由基的反应。对颗粒相β-羟基硝酸盐、二羟基硝酸盐、二羟基羰基、1,4-羟基硝酸盐和气相醛进行取样，然后使用衍生化、气相和液相色谱以及多种质谱分析技术进行鉴定和定量。由OH自由基加成到C = C双键形成的产物，包括β-羟基硝酸盐、二羟基硝酸盐、二羟基羰基（以前没有被高精度地直接定量）和醛的摩尔产率分别为0.125±0.01、0.048±0.005、0.240±0.04和0.268±0.03 （β-羟基烷氧基自由基分解的甲醛和三管/四管副产物的摩尔产率分别为0.264±0.02和0.271±0.04）。这些值得到的总摩尔产率为0.681±0.05，这与动力学测量的结果非常吻合，动力学测量表明OH自由基加成反应的比例为0.70。这些产率被用来计算所有OH自由基加成途径的分支比，包括由二羟基过氧自由基与NO反应生成二羟基硝酸盐的分支比为0.18，β-羟基烷氧自由基分解和异构化的分支比为0.47和0.53。研究结果与文献数据相结合，包括小烯烃类似反应中醛的产率测量数据、有机硝酸盐形成过程中碳数对支链比影响的模型，以及从线性烷烃研究中得到的H原子提取机制，以实现1-烯烃气相反应的完整、定量机制。研究结果也可用于构建更复杂的挥发性有机化合物反应机制。
The reactions of 1-tetradecene and 1-pentadecene, the C14and C15linear 1-alkenes, with OH radicals in the presence of NOxwere investigated in a series of environmental chamber experiments. Particle-phase β-hydroxynitrates, dihydroxynitrates, dihydroxycarbonyls, and 1,4-hydroxynitrates and gas-phase aldehydes were sampled and then identified and quantified using a suite of offline analytical techniques that included derivatization, gas and liquid chromatography, and multiple types of mass spectrometry. Measured molar yields of products formed by OH radical addition to the C═C double bond, including β-hydroxynitrates, dihydroxynitrates, dihydroxycarbonyls (which have not been previously directly quantified with high accuracy), and aldehydes were 0.125 ± 0.01, 0.048 ± 0.005, 0.240 ± 0.04, and 0.268 ± 0.03 (0.264 ± 0.02 and 0.271 ± 0.04 for the formaldehyde and tridecanal/tetradecanal co-products of β-hydroxyalkoxy radical decomposition), respectively. These values give a total molar yield of 0.681 ± 0.05, which agrees very well with the results of kinetics measurements that indicate that the fraction of reaction that occurs by OH radical addition is 0.70. The yields were used to calculate branching ratios for all OH radical addition pathways, including a value of 0.18 for the formation of dihydroxynitrates from the reaction of dihydroxyperoxy radicals with NO and values of 0.47 and 0.53 for β-hydroxyalkoxy radical decomposition and isomerization. The results were used with literature data on the yields of aldehydes measured for similar reactions of smaller alkenes, a model for the effect of carbon number on branching ratios for organic nitrate formation, and a mechanism for H atom abstraction derived from studies of linear alkanes to achieve a complete, quantitative gas-phase reaction mechanism for 1-alkenes. The results should also be useful for constructing mechanisms for more complex reactions of volatile organic compounds.