RUI: Determination of the Kinetic Expressions and Mechanisms of the Photochemical Degradation and Oxidation of Dicamba

该奖项由化学学部环境化学科学项目颁发，支持古斯塔夫斯·阿道夫斯学院阿曼达·尼诺教授的工作。她正在研究除草剂麦草畏的化学反应。尽管麦草畏在市场上已经存在了30多年，但由于新的转基因大豆植物可以耐受麦草畏，它现在被更多地用于农业领域。在2017年的生长季节，美国首次使用了这些大豆——到夏末，农田附近土地上的农民就收到了数千起投诉。空气中飘散的除草剂似乎对顺风田的作物造成了损害。在这个项目中，研究环境系统（例如水或空气系统），以了解麦草畏如何通过与环境中其他化合物的反应以及与阳光的相互作用而变化。此外，这个项目为本科生提供了研究机会，为他们进入劳动力市场或研究生或专业学校做准备。这些学生还将帮助发展和建立一个面向地区高中生的“化学之夜”。该团队还与法国的国际合作伙伴合作。从多个角度研究了氯化除草剂麦草畏的光化学和反应性以及添加剂对配方农产品的影响。这些包括表皮蜡和叶子表面的非均相光化学，气相光化学以及与主要气相氧化剂羟基自由基的非均相反应性。考察了麦草畏商业配方中表面活性剂和非活性成分对这些反应的影响。该结果为麦草畏的光降解和氧化机理及其（光）产物提供了新的思路。本研究提高了目前对麦草畏环境化学的认识。这项工作还提供了新的方法来研究化学物质吸附到表面的光解作用和与气相氧化剂的非均相反应。本科生参与这个跨学科项目的各个方面，并在广泛的领域获得经验。先前在年轻学生中取得的化学推广成功，在此基础上扩大了针对地区（主要是农村）高中学生的规划。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award by the Environmental Chemical Sciences Program of the Chemistry Division supports work by Professor Amanda Nienow at Gustavus Adolphus College. She is examining chemical reactions of the herbicide dicamba. Although dicamba has been on the market for over thirty years, it is being used more often on agricultural fields now as new genetically-modified soybean plants can tolerate dicamba. The 2017 growing season saw the first use of these soybeans in the US - and by the end of the summer, there were thousands of complaints from farmers on land adjacent to fields. Herbicide drifting through the air appeared to be causing crop damage in down-wind fields. In this project, environmental systems (for example, water or air based systems) are examined to understand how dicamba changes through reactions with other compounds in the environment and through interactions with sunlight. In addition, this project provides research opportunities for undergraduate students, which prepares them to enter the workforce or graduate or professional schools. These students will also help develop and institute a "Chemistry Night" for regional high school students. The team also collaborates with international partners in France.The photochemistry and reactivity of the chlorinated herbicide dicamba and the impact of additives in formulated agricultural products is being examined from several angles. These include heterogeneous photochemistry on the surface of epicuticular waxes and leaves, gas-phase photochemistry, and heterogeneous reactivity with hydroxyl radical, the primary gas-phase oxidant. The influence of surfactants and inactive ingredients in the commercial formulation of dicamba on these reactions is examined. The results may provide insight into the photodegradation and oxidation mechanisms and (photo)products of dicamba. This research enhances the current understanding of the environmental chemistry of dicamba. This work also provides new methods to examine the photolysis of chemicals sorbed to surfaces and heterogeneous reactions with gas-phase oxidants. Undergraduates participate in all aspects of this interdisciplinary project and gain experience in a wide range of fields. Prior success with chemistry outreach with young students is expanded upon with programming for regional, mostly rural, high school students.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.