评估Criegee中间体在烯异质自氧化过程中可能形成的机制
Meirong Zeng1, Kevin R Wilson2
1College of Smart Energy, Shanghai Jiao Tong University, Shanghai 200240, PR China.
Environmental science & technology
|June 20, 2024
概括
烯氧化涉及由β-氧过氧基 (β-OH-RO) 形成的Criegee中间体 (CI). 这项研究发现,单分子途径最能解释素自氧化过程中的CI形成.
科学领域:
- 大气化学 大气化学
- 环境科学 环境科学
- 有机地化学 有机地化学
背景情况:
- 有机分子通过氧化途径降解,包括涉及自由基的异质自氧化.
- 烯的一种新型自氧化机制涉及基 (OH) 激素和Criegee中间体 (CI).
- 来自β-过氧基 (β-OH-RO) 的CI形成途径仍然不确定,其中可能包括单分子或双分子反应.
研究的目的:
- 调查在烯自氧化过程中由β-氧过氧基 (β-OH-RO) 形成克里奇介质 (CI) 的机制性途径.
- 为了评估单分子与双分子途径的动态可行性,用于CI生成.
- 确定最准确的机制来解释对烯氧化产物的实验观测.
主要方法:
- 综合动力学建模与多相氧化测量由基 (OH) 基启动的烯.
- 评估了CI形成的三个机制情景:β-OH-RO2•的单分子键分裂 (情景1) 和两个双分子通路 (情景2和3).
- 分析了实验数据,包括有效吸收系数与[OH]相比,以及主要氧化产物 (化物,二次臭氧化物) 的形成动力学.
主要成果:
- 场景1,建议从β-OH-RO2•中形成CI的单分子途径,最好复制实验数据集.
- 选择的机制准确地预测了有效的吸收系数和化物和二次臭氧化物形成的动力学.
- 从β-OH-RO2•中形成CI的单分子途径被发现是动态可行的.
结论:
- β-氧过氧基 (β-OH-RO2•) 的单分子分解是烯自氧化过程中最有可能形成Criegee中间体 (CI) 的途径.
- 这一发现促进了对环境中复杂有机分子降解机制的理解.
- 建议进行进一步的理论研究,以充分阐明CI和β-OH-RO2之间的机械联系.
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