Transition States for Surface Reactions

该研究项目在卡内基梅隆大学Andrew Gellman教授的实验室进行，得到了分析和表面化学计划的支持。 它是集中在理解和表面催化反应的过渡态的热力学表征。 利用有机反应物上的取代基效应，通过一系列的测试反应，探讨了表面反应过渡态的性质和热力学稳定性。 不同程度的氟取代影响的活化能和稳定性的过渡态的探针反应，包括脱氯的氯氟烃，羧酸的去质子化，和O-H键断裂醇。 实验测得的能量与高层次的电子结构计算的结果进行了比较，以解释表面反应过渡态的性质。对表面催化化学反应中过渡态的详细了解有助于催化剂设计和工艺优化。 通过使用物理有机概念，如取代基对反应速率的影响，Gellman教授和他的同事正在探索一系列探测反应的表面过渡态的性质。 从这些测量的结果进行比较与计算，以发展一个一般的理解的性质的表面反应过渡态。

This research project, carried out at Carnegie Mellon University in the laboratory of Professor Andrew Gellman, is supported in the Analytical and Surface Chemistry Program. It is focussed on the understanding and thermodynamic characterization of the transition state for surface catalyzed reactions. Using substituent effects on organic reactants, the nature and thermodynamic stability of the surface reaction transition state is probed for a series of test reactions. Varying degrees of fluorine substitution affects the activation energy and stability of the transition state for probe reactions including dechlorination of chlorofluorocarbons, deprotonation of carboxylic acids, and O-H bond cleavage in alcohols. Experimentally measured energetics are compared with the results of high level electronic structure calculations to interpret the nature of the surface reaction transition state. A detailed understanding of the transition state in surface catalyzed chemical reactions is useful in catalyst design and process optimization. By using physical organic concepts such as substituent effects on reaction rates, Professor Gellman and his coworkers are probing the nature of the surface transition state for a series of probe reactions. Results from these measurements are compared with calculations, in order to develop a general understanding of the nature of the surface reaction transition state.