Laboratory Studies of Aldehyde Reactions of Atmospheric Importance

该项目的目的是提高对大气醛（RCHO）反应的动力学、机理和产物的理解。 醛的光解在光化学烟雾和区域臭氧的形成中起着至关重要的作用，通过形成自由基，如HCO（甲酰基自由基），并随后转化为HO2和OH自由基。 醛的光裂解量子产率在光化紫外区（290 nm）表现出显著的波长依赖性。 尽管醛的光解在对流层的化学的重要性，醛的光解途径和量子产率的几个波长依赖的研究已经进行的条件下，可以很容易地外推到那些的大气。 在本研究中，将脉冲激光光解与光腔衰荡光谱、FTIR和质谱相结合，研究C3和C4醛、蒎醛和桂皮醛（萜烯氧化产物）以及乙醛和乙二醛（芳香族降解产物）的光解。 此外，醛烷基结构和光解离量子产率之间的关系将进行研究。

The objective of this project is to improve understanding of the kinetics, mechanisms, and products of atmospheric aldehyde (RCHO) reactions. Aldehyde photolysis plays a crucial role in the formation of photochemical smog and regional ozone, via formation of free radicals such as HCO (formyl radicals) and their subsequent conversion into HO2 and OH radicals. Photofragmentation quantum yields of aldehydes exhibit dramatic wavelength dependence in the actinic uv region (290 nm). Despite the importance of aldehyde photolysis in the chemistry of the troposphere, few wavelength dependent studies of aldehyde photodissociation pathways and quantum yields have been carried out under conditions that can be readily extrapolated to those of the atmosphere. In this proposal, the photolysis of C3 and C4 aldehydes, pinonaldehyde and caronaldehyde (terpenes oxidation products), and glycidaldehyde and glyoxal (aromatic degradation products) will be studied by combining pulsed laser photolysis with cavity ring-down spectroscopy, FTIR, and mass spectrometry for product characterization. In addition, the relationship between aldehyde alkyl group structure and photodissociation quantum yields will be investigated.