Abstract:

Today, more attention is paid to the production of fine chemicals from sustainable raw materials via atom efficient, safe, and energy-efficient processes in modern organic synthesis. Teaching these "green" concepts also becomes a central task in chemistry education. Herein, we introduce our efforts for developing a series of teaching experiments on the chemistry of renewable substances from biomass and providing an organic chemistry module on the catalytic green epoxidation of limonene. Limonene is a monoterpene isolated from orange peels, and its 1, 2-epoxide is found to copolymerize with CO₂ leading to a high-performance biodegradable polymer. In our design, with 30% H₂O₂as a safe and atom efficient oxidant, and recyclable tetrabutylammonium polyphosphotungstate as a phase transfer catalyst, limonene is efficiently oxidized to its 1, 2-epoxide in a regioselective fashion. This experiment not only boosts the students' enthusiasm toward learning a structural based activity in electrophilic addition of alkenes along with ¹H NMR and GC directed structural analysis, but also encourages students toward creative thinking and research in green and sustainable chemistry by demonstrating the potential of this epoxidation method on industrial production of biodegradable materials.

Key words: Epoxidation, Green chemistry, Limonene, Organic synthesis