Laboratory Studies of Tropospheric Sulfur Chemistry

对流层硫化学的实验室研究

• 批准号: 8802386
• 负责人: Paul Wine
• 金额: $ 36.1万
• 依托单位: Georgia Tech Research Corporation - GA Tech Research Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-04-15 至 1991-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8802386&HistoricalAwards=false
• 关键词: Laboratory; Studies; Tropospheric; Sulfur; Chemistry

The atmospheric sulfur cycle has been the subject of intensive investigation in recent years because of the need to assess the contribution of anthropogenically produced sulfur to such problems as acid rain, visibility reduction, and climate modification. In heavily industrialized regions such as the eastern United States and western Europe, anthropogenic sulfur magnitude. On a global scale, however, natural sulfur emissions are thought approximately to equal those from anthropogenic sources. An understanding of the natural sulfur cycle is thus required in order to establish a "base line" with which anthropogenic perturbations can be compared. A substantial measurement data base for the key reduced sulfur species CS2, COS, and CH3SCH3 (DMS) has become available in recent years. Laboratory research aimed at identifying major sulfur oxidation pathways and quantifying the rates of these pathways has also progressed rapidly. Nonetheless, major uncertainties in the atmospheric chemistry of organosulfur compounds remain. This research is aimed at elucidating the kinetics and reaction mechanisms which control the atmospheric oxidation of reduced sulfur compounds, i.e. H2S, CS2, COS, mercaptans, sulfides and disulfides. Direct observation of reactive intermediates and relatively stable products in "real time" is emphasized because only through such observations can results with a unique interpretation be obtained. Some specific experimental investigations which are to be undertaken include kinetics studies of CH2S reactions with O3, HO2, and NO2, kinetics studies of IO reactions with thiols, sulfides, and disulfides, determination of the product yields of SH, CS, S2, HO2, COS, CO, and CO2 from the CS2OH+O2 reaction, determination of CH3S yields from reactions of OH and NO3 with organosulfur compounds, kinetic studies of the reactions of OH and NO3 with dimethylsulfoxide, and investigations of the mechanisms for producing the stable end products SO2, CH3SO3H, and (CH3)2SO via the OH-, NO3-, and IO-initiated oxidations of organosulfur compounds. The experimental methods to be employed involve coupling laser flash photolysis production of unstable reactants with time resolved detection of intermediates and end products by laser induced fluorescence, long path UV-visible absorption, or long path infrared absorption. Most experiments will be carried out under atmospheric conditions of temperature, pressure, and gas composition.

近年来，大气硫循环一直是深入研究的主题，因为需要评估人为产生的硫对酸雨、能见度降低和气候改变等问题的贡献。 在美国东部和西欧等工业化程度较高的地区，人为产生的硫含量很高。 然而，在全球范围内，自然硫排放量被认为大致等于人为排放量。 因此，需要了解自然硫循环，以便建立可以与人为扰动进行比较的“基线”。 近年来，关键还原硫物种 CS2、COS 和 CH3SCH3 (DMS) 的大量测量数据库已经可用。 旨在确定主要硫氧化途径并量化这些途径速率的实验室研究也取得了迅速进展。 尽管如此，有机硫化合物的大气化学仍然存在重大不确定性。 本研究旨在阐明控制还原性硫化合物（即H2S、CS2、COS、硫醇、硫化物和二硫化物）大气氧化的动力学和反应机制。 强调“实时”直接观察反应中间体和相对稳定的产物，因为只有通过这种观察才能获得具有独特解释的结果。 即将进行的一些具体实验研究包括CH2S与O3、HO2和NO2反应的动力学研究，IO与硫醇、硫化物和二硫化物反应的动力学研究，测定CS2OH+O2反应中SH、CS、S2、HO2、COS、CO和CO2产物产率，测定OH和NO3与OH和NO3反应中CH3S产率。 有机硫化合物，OH和NO3与二甲亚砜反应的动力学研究，以及通过OH-、NO3-和IO引发的有机硫化合物氧化产生稳定最终产物SO2、CH3SO3H和(CH3)2SO的机制的研究。 所采用的实验方法包括将不稳定反应物的激光闪光光解生产与通过激光诱导荧光、长程紫外-可见吸收或长程红外吸收对中间体和最终产物进行时间分辨检测相耦合。 大多数实验将在温度、压力和气体成分的大气条件下进行。