Investigations of isoprene oxidation multiphase chemistry - Part II

异戊二烯是对流层中NMHC有机碳的最大来源，异戊二烯的氧化反应与臭氧产生和有机物质形成等大气过程有关。因此，异戊二烯化学在过去几年中被深入研究。现有的研究大多集中在气相和多相反应。与此相反，异戊二烯氧化过程中的多相化学过程大多被忽略，除了较小的C2和C3产物，如乙二醛，甲基乙二醛，丙酮酸和羟基丙酮。对流层多相化学转化的描述甚至对这些化合物仍然是基于许多假设和包含很大的不确定性。这里提出的项目旨在通过考虑从第一代产品开始的多相化学过程来改进和扩展异戊二烯氧化机理的现有知识。为了研究这些多相化学过程，将应用实验室和建模研究。改进和扩展的异戊二烯氧化机理将用于评估多相化学在异戊二烯降解过程中的作用和影响。为了获得必要的实验数据的机制开发，实验室研究的动力学，特别是对早期异戊二烯氧化产物的产品形成将进行和化学机理模块将开发。将进行室内实验，以验证实验室和建模研究的结果。在本项目中，将系统地研究甲基丙烯醛、甲基乙烯基酮、甲基丙烯酸和丙烯酸与OH、NO3和臭氧的水相氧化反应的动力学和机理。

Oxidation reactions of isoprene, which constitutes the biggest source for NMHC organic carbon in the troposphere, are relevant for atmospheric processes such as ozone production and formation of organic mass. Therefore, isoprene chemistry was intensively studied in the last years. Most of the existing studies are focused on the gas phase and heterogeneous reactions. In contrast to this multiphase chemical processes during the isoprene oxidation have been mostly neglected, except for smaller C2 and C3 products such as glyoxal, methylglyoxal, pyruvic acid and hydroxyacetone. The description of the tropospheric multiphase chemical conversion even of for these compounds is still based on many assumptions and contains large uncertainties. The project proposed here aims to improve and extend the current knowledge on the isoprene oxidation mechanism by considering multiphase chemical processes already from the first product generation on. In order to study these multiphase chemical processes, laboratory and modelling studies will be applied. The improved and extended isoprene oxidation mechanism will be used to evaluate the role and effects of multiphase chemistry during the isoprene degradation processes. To obtain the necessary experimental data for the mechanism development, laboratory studies on the kinetics and in particular on the product formation of early isoprene oxidation products will be carried out and a chemical mechanism module will be developed. Chamber experiments will be performed to verify the results from the laboratory and modelling studies. Within this project, the aqueous phase oxidation reactions of methacrolein, methyl vinyl ketone, methacrylic acid and acrylic acid with OH, NO3 and ozone will be systematically investigated with regard to both their kinetics and mechanisms.