Electrochemical Ethylene Oxide Synthesis from Ethanol

Ethylene oxide is a crucial precursor for chemical and plastic synthesis. Its production is carbon-intensive, however, releasing 1.9 tons of CO2 per ton of product. Reducing this footprint is possible if ethylene oxide is produced using both a renewable substrate and renewable energy. Herein, we pioneer a sustainable pathway to ethylene oxide via the electrochemical oxidation of ethanol to 2-chloroethanol and its subsequent alkaline cyclization in a single electrochemical cell, using chloride ions as catalysts. This approach is enabled by the electrochlorination of ethanol to 2-chloroethanol, which requires the activation of an inert C(sp3)–H bond and is shown here for the first time. We investigate the branchpoints controlling the selectivity of this chlorination and show how they are influenced through reaction conditions and electrode material engineering. Our method is generalizable to the production of other valuable chemicals and strengthens the foundation for sustainable chemical synthesis using renewable energy.