RUI: Experimental and Theoretical Investigation of Threshold Energy Barriers and Substituent Effects for the 1,2-Halogen Interchange Reaction in Haloalkanes

北卡罗来纳大学阿什维尔分校的伯特·霍姆斯和乔治·希尔德得到了实验物理化学项目的支持，对化学活化氢卤烷的单分子反应动力学进行了合作实验和理论研究。这项研究建立在pi先前对一种不寻常的气相机制的研究基础上，该机制涉及相邻碳上卤素的交换。以氢卤烷为重点，计划确定各种1,2卤素交换反应和1,2- hx（其中X = F， Cl或Br）消除反应的阈值能垒和取代基对这些能垒的影响。电子结构计算将给出反应物和过渡态的频率和转动惯量，这些将与RRKM理论一起用于计算速率常数，并允许分析结构-反应性关系的趋势。该项目的研究成果可以增进对涉及氟氯烃的燃烧、焚烧和大气化学过程的了解。本研究期望提供充足的机会，让学生参与旨在培养分析思考能力和解决问题能力的研究，以加强本科教育，并鼓励他们在化学科学领域从事高级工作的兴趣。

Bert Holmes and George Heard of the University of North Carolina at Asheville are supported by the Experimental Physical Chemistry Program to carry out a collaborative experimental and theoretical study of the kinetics of unimolecular reactions of chemically activated hydrohaloalkanes. The research builds on the PIs' previous investigations of an unusual gas phase mechanism involving the exchange of halogens on adjacent carbons. Focusing on hydrohaloalkanes, the plan is to determine threshold energy barriers and the effect of substituents on these energy barriers for various 1,2 halogen interchange reactions and for the 1,2-HX (where X = F, Cl, or Br) elimination reaction. Electronic structure calculations will give the frequencies and moments of inertia of the reactant and transition state, and these will be used with RRKM theory to calculate rate constants and permit the analysis of trends in the structure-reactivity relationships. Research outcomes from this project could improve the understanding combustion, incineration, and atmospheric chemical processes involving hydrochlorofluorocarbons. This research is expected to provide ample opportunities to enhance undergraduate education by involving students in research that is designed to develop analytical thinking skills and problem-solving ability, and encourage interest in pursuing advanced work in the chemical sciences.