Evaluating Green Chemistry Through a Bromination Reaction

Green Chemistry is an approach to chemical product and process development that aims to minimize or eliminate toxic substances, while taking into consideration the entire life cycle of a chemical compound from synthesis through to disposal. The Twelve Principles of Green Chemistry guide the development of chemicals toward waste prevention, purity and efficiency, as well as safer chemical handling and use. To investigate the application of the Twelve Principles of Green Chemistry in a lab setting, I performed a bromination reaction on trans-stilbene to create dibromostilbene, and then assessed the yield and atom economy of the reaction. In this experiment, the yield of the formation of dibromostilbene was relatively high at approximately 77.5 %; the atom economy was calculated at 100%, indicating efficiency of reactants. However, after assessing environmental impact using additional green metrics, the environmental factor (EF) and process mass intensity (PMI) were calculated at 22.9 and 31.13 respectively; indicating a large amount of material waste was created in the process. These results indicate that a high yield does not indicate the sustainability of an experiment, as well as emphasizing the need to apply the Principles of Green Chemistry to future chemical developments, promoting waste reduction, and atom economy by using safer solvents. This experience has led me to a more thorough understanding of how sustainable considerations influence the design and development of responsible chemical products.