CAS: Oxidation from the Top Down and the Bottom Up by the OH Radical: Lifetimes and Fates of Important Ingredients of Pesticides, Pharmaceuticals, and Consumer Products

CAS： OH 自由基自上而下和自下而上的氧化：农药、药品和消费品重要成分的寿命和命运

• 批准号: 2303948
• 负责人: Barbara Finlayson-Pitts
• 金额: $ 81.92万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303948&HistoricalAwards=false
• 关键词: CAS; Oxidation; Top; Down; Bottom

With support from the Environmental Chemical Sciences Program in the Division of Chemistry, Professor Barbara Finlayson-Pitts and her team at the University of California, Irvine will study the degradation of contaminants of emerging concern in the environment. These include a broad spectrum of human-made products, including pesticides, pharmaceuticals, and consumer products. Their deleterious impacts on humans and the environment often become apparent only after such compounds have become distributed widely in air, water, and soils. This is to a significant extent due to their degradation in the environment to form unanticipated products that are more toxic than the parent compound. The focus of this project is on compounds that contain nitrogen. The goals are to measure how fast selected members of this group, which includes pesticides and pharmaceuticals, degrade on contact with atmospheric constituents, and to identify the products that are formed. The data generated in this project will form the core needed to assess how these synthetic chemicals are degraded under atmospheric conditions. Through a partnership with a local environmental justice community group, high school students from historically disadvantaged communities will join the team to work in their labs during the summer. The proposed research will also provide training to undergraduates and postdoctoral fellows in the integration of experiment and theory to address current important environmental problems.Two different environmentally relevant oxidation systems will be explored: hydroxyl radical (OH) oxidation from the top down, representing gas phase OH impinging on a solid, and OH oxidation from the bottom up, representing oxidation of an adsorbed organic by OH generated from a nitrite ion or TiO2 substrate. Top-down studies will probe the oxidation of thin films of the organics using attenuated total reflectance-Fourier transform infrared (ATR)-FTIR spectroscopy or in situ oxidation of organic particles in a flow system. Bottom-up studies will use OH from photolysis of solid nitrite salts or TiO2 in the presence of water. Loss of the organics and formation of products will be monitored using IR, UV and a variety of mass spectrometric techniques. The structures of the strongest binding complexes between OH and the organics will be predicted using semi-empirical quantum chemical calculations, and molecular dynamics simulations will be applied to each of these complexes in order to provide insights into the molecular basis for the experimental results. This combination of experiment and theory will help elucidate the role of OH oxidation in the degradation and fates of these synthetic compounds by these two different oxidation systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系环境化学科学计划的支持下，芭芭拉·芬莱森·皮茨（Barbara Finlayson Pitts）教授及其在加利福尼亚大学的团队将研究环境中新兴关注的污染物的退化。 其中包括各种各样的人造产品，包括农药，药品和消费产品。它们对人类的有害影响和环境通常只有在这种化合物广泛分布在空气，水和土壤中后才会显而易见。这在很大程度上是由于它们在环境中的退化而形成比母体化合物更具毒性的意外产品。该项目的重点是含有氮的化合物。目标是衡量该组的选定成员的速度，其中包括农药和药物，与大气成分接触时降解并识别形成的产品。该项目中产生的数据将构成评估在大气条件下如何降解这些合成化学物质所需的核心。通过与当地环境司法社区团体的合作，来自历史上不利社区的高中生将加入团队在夏季在实验室工作。拟议的研究还将在实验和理论的整合中为本科生和博士后研究员提供培训，以解决当前重要的环境问题。将探索两个与环境相关的氧化系统：羟基自由基（OH）氧化与固体和OH氧化的氧化作用，并在固体上构成氧化器，并在固体中构成氧化器，并在固体上构成了氧化的氧化，并且是由固体构成的，并且是氧化的氧化作用，并且是氧化的氧化作用，并且是氧化的氧化作用，并且是一种氧化的氧化作用，并且是氧化的氧化作用，并且是氧化的氧化作用，并且是一种氧化的氧化作用，并且是一种氧化的氧化作用，并且是一种氧化的氧化作用，并且是一种氧化的氧化作用，并且是由固体和氧化的氧化作用。亚硝酸盐离子或TIO2底物。自上而下的研究将使用衰减的总反射率转换红外（ATR） - fTRESCOPY或原位氧化有机粒子在流动系统中探测有机物的薄膜的氧化。自下而上的研究将在水存在下使用固体亚硝酸盐或TIO2的光解。有机物的损失和产品的形成将使用IR，紫外线和各种质谱技术来监测。 OH和有机物之间最强结合复合物的结构将使用半经验量子化学计算进行预测，并将分子动力学模拟应用于这些复合物中的每个复合物，以便为实验结果提供洞察分子基础。实验和理论的这种结合将有助于阐明OH氧化在这两种不同的氧化系统中的降解和命运中的作用。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来支持的。