Advancing Green Chemistry Education: Safe and Sustainable Click Chemistry with Biodegradable HPMC-Encapsulated Catalysts

The implementation of safe practices in undergraduate laboratories is paramount for mitigating accidents and fostering responsible laboratory techniques. This experiment introduces the use of biodegradable hydroxypropyl methylcellulose (HPMC) capsules for handling catalysts and a potentially hazardous but highly important and a useful reagent, sodium azide, in water-based two-step one-pot click chemistry, aligning with Green Chemistry Principles by emphasizing cleaner solvents, energy-efficient design, and the reduction of chemical waste while teaching an important organic transformation and essential technical skills to undergraduate students. In these domino nucleophilic substitution and click reactions, the post-reaction product is filtered, eliminating the reliance on toxic organic solvents for extraction and purification, while the generated waste can be repurposed within the research laboratory, thereby enhancing sustainability. Designed for a 3 h lab session, this experiment is characterized by its safety, reproducibility, adaptability, and intensive learning opportunity, making it suitable for different levels of the undergraduate curriculum. By engaging in this practice, students cultivate a sense of responsibility toward Green Chemistry and are better equipped to make environmentally informed decisions in future research or industry roles.