The coupling of carbon dioxide (CO2) and epoxides has been studied for over 50 years with many different epoxides to generate value-added polycarbonate and cyclic carbonate materials. Unfortunately, the use of high pressures of CO2 as well as highly developed bifunctional catalysts have limited undergraduate exposure to this chemistry. The Poland Group has modified a popular undergraduate liquid CO2 extraction experiment to perform CO2/epoxide coupling under more mild conditions for use in an undergraduate teaching laboratory. The coupling of epichlorohydrin and dry ice has been optimized using 1 mol% (salen)AlCl and 2 mol% nBu4NBr, yielding 10.4 ± 3.9% conversion to epichlorohydrin carbonate in just 10 minutes. Although (salen)AlCl is relatively high-cost, the same system can have fresh dry ice reintroduced up to 5 times, improving the conversion to over 25% by 1H NMR. Optimization of catalyst, cocatalyst, reaction time, and epoxide choice will be discussed. From reaction setup through data collection, the entire laboratory experiment can be finished within a four-hour laboratory period.

Coupling epoxides and dry ice under mild conditions: Development of an undergraduate laboratory experiment

2019 Spring National Meeting

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