The Dynamic (Organic) Chemistry Laboratory Part II

4) Ongoing investigations replace repeated experiments. It has been customary to repeat the same student experiments year after year without any acknowledgment of past or future experience with the experiment. However, in the dynamic chemistry laboratory, experiments can be performed focusing on the same technique(s) but instead of simply repeating last year’s work the previous year’s results can be used as a starting point to extend the knowledge of an experimental topic. For example, the traditional “banana oil” (isopentyl acetate) experiment can be easily extended to any Fischer Esterification reaction of a primary or secondary alcohol with an appropriate carboxylic acid. Therefore, we have done Fischer Esterification with simple alcohols and o, m, and p toluic acids.

5) Continued analysis of student products. In some cases student products lead to further avenues of investigation that can be pursued “offline.” For example, the phenylmagnesiumbromide Grignard addition to the positional isomers of methylcyclohexanone creates an unequal distribution of diastereomers. Resolving the mixtures and interpreting the results can lead to a long term investigation that goes beyond the week-to-week time frame that is imposed during the semester. More open-ended experiments open new avenues of investigation for both instructor and students. Course laboratory work is a great jumping off point to get students involved in individual research projects.

6) Repeat an experiment the next week. Our example of this one is to perform the extraction of caffeine from tea one week, and do the extraction of caffeine from energy drinks the next week. Students use their experience the first week to design a similar experiment the following week. This follows a familiar research pattern of mastering a “literature” procedure in order to build skills to perform an original research project related to the literature procedure. Certainly, an important function of the course laboratory is to introduce and practice new experimental techniques. However, once a technique is established, it can be extended to encompass an original research avenue.

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