Organic chemistry students traditionally lack in their understanding of reaction mechanisms; particularly in how they are derived and justified. In this novel experiment targeting second year undergraduates, students used Infrared Spectroscopy (IR) in order to track the reaction progress of two distinct aldol reactions. Students worked in two pairs, one focusing on the traditional aldol reaction (two units of propionaldehyde combining via an enol intermediate) and the other focusing on a catalyzed aldol reaction (propionaldehyde catalyzed by proline, showing an imine intermediate). During the course of the reactions, students used IR scans and guided questions to experimentally derive the reaction mechanisms. After the pairs of students analyzed their individual reaction, they formed groups of four in order to further analyze and compare the two mechanisms. This comparison allowed students to consider why chemists use different reaction conditions to reach the same product. The focus of this experiment is to improve understanding of reaction mechanisms and how scientists propose and derive mechanisms, while giving students practical experience with IR spectroscopy. Learning outcomes in this experiment are evidenced by the efficacy of the justification for the mechanism and the alignment between structures and IR data. Additionally, the post-lab report for this experiment includes a theoretical situation in which students develop their own experiment to probe a reaction mechanism. Data regarding learning outcomes will be presented.

Developing an undergraduate lab that informs how experimental data guide the development of reaction mechanisms

2019 Spring National Meeting

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