Eight-Fold Intensification of Electrochemical Azidooxygenation with a Flow-Through Electrode

Finding ways to reduce reactor volume while increasing product output for electro-organic reactions would facilitate the broader adoption of such reactions for the production of chemicals in a commercial setting. This work investigates how the use of flow with different electrode structures impacts the productivity (i.e., the rate of product generation) of a TEMPO-mediated azidooxygenation reaction. Comparison of a flow and batch process with carbon paper (CP) demonstrated a 3.8-fold-higher productivity for the flow reactor. Three custom carbon electrodes, sintered carbon paper (S-CP), carbon nanofiber (CNF), and composite carbon microfiber-nanofiber (MNC), were studied in the flow reactor to evaluate how changing the electrode structure affected productivity. Under the optimum conditions, these electrodes achieved productivities 5.4, 6.5, and 7.8 times higher than the average batch reactor, respectively. Recycling the outlet from the flow reactor with the MNC electrode back into the inlet achieved an 81% yield in 36 min, while the batch reactor obtained a 75% yield in 5 h. These findings demonstrate that the productivity of electro-organic reactions can be substantially improved through the use of novel flow-through electrodes.