Excellence in Research: A Computational Study of the Gas-Phase Reactions of Simple Epoxides and their Radicals

通过这一奖项，化学结构、动力学和机制-B项目支持路易斯安那州泽维尔大学的凯瑟琳·摩根教授和她的学生学习环氧化物的化学，环氧化物是一种在大气中常见的挥发性有机化合物。越来越多的市民认识到生产和储存危险化学品的工业工厂的潜在危险，其中一个主要担忧是挥发性有机化合物(VOC)释放到他们呼吸的空气中。这项研究是关于“环氧化物”类化合物的。环氧乙烷和环氧丙烯是环氧化物家族中常见的商品化学品，具有各种重要的商业用途，但它们也具有致癌作用。通过了解可能的分解机制和速率，了解这些和相关VOC在大气中的命运是至关重要的。拟议的计算模拟研究旨在扩大我们对降解反应的理解，并有可能提出能够修复污染物的新反应。这项研究是为路易斯安那州泽维尔大学的本科生和理科专业的本科生和理科专业的学生设计的，该大学主要是本科生和历史黑人学院或大学(HBCU)，那里的学生大多是非裔美国女性。计算分析为本科生提供了极好的培训经验，为他们在STEM(科学、技术、工程和数学)领域的研究生学习和职业生涯做好准备。这项研究还将使学生能够将基础科学研究与作为该项目基础的现实世界问题联系起来。拟议的计算研究涉及简单环氧化物的气相自由基反应。感兴趣的环氧化物包括环氧乙烷、环氧丙烯、顺式和反式-2-丁烯环氧化物、2-甲基环氧丙烯和环氟丙烷。使用商用软件，将考虑三种类型的计算，以探索取代基对环氧化物反应性的影响：(1)环氧化物的键离解能；(2)母体环氧化物和/或其自由基对的降解；(3)羟基和其他自由基物种与环氧化物的加成反应。总之，这些计算将深入了解环氧化物在气相中的行为，以及取代基对环氧化物反应性和分解产物的影响。通过该项目，针对少数民族本科生的详细培训计划有望为国家多元化劳动力的发展做出重要贡献。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With this award, the Chemical Structure, Dynamics, and Mechanisms-B program is supporting Professor Kathleen Morgan and her students at Xavier University of Louisiana to study the chemistry of epoxides, a type of volatile organic compound which is commonly found in the atmosphere. Increasingly, citizens are recognizing the potential dangers of industrial plants that produce and store hazardous chemicals, and one major concern is the release of volatile organic compounds (VOC) into the air they breathe. This study is concerned with the 'epoxide' class of compounds. Ethylene oxide and propene oxide are common commodity chemicals of the epoxide family with a variety of important commercial purposes but they are also carcinogenic. Understanding the fate of these and related VOC in the atmosphere, through knowledge of likely decomposition mechanisms and rates, is critical. The proposed computational modeling study seeks to extend our understanding of the degradation reactions, and has the potential to suggest new reactions that can remediate pollutants. The study is designed for full participation by undergraduate research students from Xavier University of Louisiana, a primarily undergraduate and Historically Black College or University (HBCU), where the majority of students are African American women, and science majors. The computational analyses provide excellent training experiences for undergraduates that will prepare them for graduate studies and careers in STEM (science, technology, engineering and mathematics) fields. This study will also enable students to connect basic science research to the real-world problems that underlie this project. The proposed computational study is concerned with gas-phase radical reactions of simple epoxides. Epoxides of interest include ethylene oxide, propene oxide, cis- and trans-2-butene oxide, 2-methylpropene oxide, and epifluorohydrin. Three types of calculations, using commercially-available software, will be considered to explore the influence of substituents on epoxide reactivity: (1) epoxide bond dissociation energies; (2) degradation of parent epoxides and/or their radical counterparts; and (3) addition reactions of hydroxyl radical and other radical species to epoxides. Together, these calculations will provide insight into the behavior of epoxides in the gas phase, and the effects of substituents on epoxide reactivity and decomposition products. Through this project, the detailed training program for undergraduate minority students is expected to make an important contribution to the development of a diverse workforce for the nation.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.