Bifunctional Phase-Transfer Catalysis for CO ₂ Cycloaddition to Epoxides: A Sustainable and Practical Undergraduate Laboratory Experiment

Incorporating cutting-edge research on carbon dioxide (CO2) utilization into the undergraduate curriculum is an effective way to bridge foundational knowledge with real-world sustainability challenges. We present a comprehensive laboratory experiment where students investigate the efficacy of a bifunctional urea-quaternary ammonium salt catalyst in the solvent- and additive-free cycloaddition of CO2 to epoxides under mild conditions (atmospheric pressure, 80 °C). This module provides an integrated learning experience that spans catalytic reaction, advanced spectroscopic characterization (NMR, FT-IR), and green metrics analysis. By applying the presynthesized organocatalyst to convert 2-(benzyloxymethyl)oxirane into the corresponding cyclic carbonate with high efficiency (up to 91% yield) and 100% atom economy, students gain practical insights into sustainable catalysis, carbon capture, and the critical evaluation of chemical processes against the Twelve Principles of Green Chemistry. This experiment successfully transforms a contemporary research theme into an accessible and impactful educational module that cultivates both technical skills and environmental responsibility in future chemists.