Kinetic and mechanistic study of the degradation of selected oxygenated volatile organic compounds (OVOCs) by atmospheric oxidants

本项目的总体目标是在大体积光反应器中调查大气氧化剂与挥发性有机化合物(VOCs)反应的动力学和机理，这些化合物以前没有得到深入研究(α，β-不饱和含氧物和环状含氧物)，特别侧重于将调查扩展到大气条件，以更好地了解低NO下的过氧基化学。这项工作的第一个目标将是利用相对动力学技术获得选定的α，β-不饱和含氧物和环状含氧物在室温下与OH和NO3自由基以及臭氧和氯原子的反应的速率系数。第二个也是更重要的目标是对氧化剂与选定的α，β-不饱和含氧物和环状含氧物的反应进行动力学和机理研究。这些实验将以不同于之前的研究的方式进行。它们将在精心设计的高和低NO条件下进行，以分析产品和产量如何随着氧化剂介导的化合物降解产生的RO2自由基的寿命被调节到接近对流层中普遍存在的水平而变化。其目的是开发不仅代表高NO对流层体系，而且代表低NO体系的机制，其中过氧基化学将占主导地位，目前对绝大多数VOC了解较少。为了支持低NO产物的研究，将对氧化剂与具有代表性的α、β不饱和含氧物和环状含氧物反应中的过氧基化学进行高水平的量子计算。

The overall aim of the present project is the investigation in a large volume photoreactor of the kinetics and mechanisms of the reactions of atmospheric oxidants with volatile organic compounds (VOCs), which have not previously been subject to in-depth investigation (alpha,beta-unsaturated oxygenates and cyclic oxygenates) with particular focus been placed on extending the investigations to atmospheric conditions to better understand peroxy radical chemistry at low-NO. The first objective of the work will be to obtain rate coefficients for the reactions of the selected alpha,beta-unsaturated oxygenates and cyclic oxygenates with OH and NO3 radicals, O3 and Cl atoms at room temperature using a relative kinetic technique.The second and more important objective is to perform kinetic and mechanistic investigations on the reactions of the oxidants with the selected alpha,beta-unsaturated oxygenates and cyclic oxygenates. The experiments will be performed differently to previous investigations. They will be performed under carefully chemically engineered high- and low-NO conditions to analyze how products and yields change as the lifetimes of the RO2 radicals, produced in the oxidant-mediated degradation of the compounds are regulated to levels approaching those prevalent in the troposphere. The aim is to develop mechanisms which are representative of not only high-NO tropospheric regimes but also low-NO regimes where peroxy radical chemistry will dominate and is currently poorly understood for the vast majority of VOCs.To support the low-NO product investigations high level quantum calculations for the peroxy radical chemistry in the reactions of the oxidants with representative alpha,beta-unsaturated oxygenates and cyclic oxygenates will be made.