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

Abstract

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.

Mxene-Cu Electrified Membranes with Confined Lamellar Channels for the Flow-through Electrochemical Reduction of Nitrate to Ammonia

“…Significantly, as separation devices, EMs are inherently very rich in permeation channels, such as nanofluidic or microfluidic ones, which are well suited to improve the mass transport of reactants in a flow-through mode. Meanwhile, different from common flow-through electrodes with unimpeded pathways, − the channels in EMs are relatively narrow and confined, which would not only better increase the opportunity for contact between the permeable substances and the electrode materials but also regulate the residence time of reactants in the electrodes; thus, it is good for the electrochemical reactions within the EMs. − Also, from another perspective, the unique retention function of EMs could serve to protect the catalytic centers especially those inside the membrane electrodes from interference by other species, − which will be extremely beneficial for maintaining the catalytic performance of electrodes in complex environments. Thus, the use of EMs as flow-through electrodes could emerge as a promising alternative to overcome the limitations of conventional electrocatalysts.…”

Polymer up-cycling by mangana-electrocatalytic C(sp3)–H azidation without directing groups

“…1D). [33][34][35][36][37][38][39][40][41][42][43][44][45] However, thus far electrosynthetic approaches have proven to be limited to chlorination and cyanation of p-conjugated polymers in the solid lm state. [46][47][48][49][50][51][52][53][54] Consequently, we wondered whether metallaelectro-catalyzed C(sp 3 )-H azidation 55 would enable selective electrooxidation for the up-cycling of polymer waste.…”

Electrochemically Enabled Total Syntheses of Natural Products

“…Electrochemical methodology and the community of researchers involved in this exciting area of chemistry expands on a daily basis. Investigators such as Opatz and Waldvogel, [13–18] Baran, [19–28] Shono, [29,124,125,138,140,224] Moeller, [77,79,108,143] Little, [30–44] Lin, [45–54] and Stahl [55–62] are just a few of the researchers that have been integral to growing the available electrochemical toolset, educating the broader synthesis community, and drawing these techniques into mainstream organic synthesis. Electrochemical toolsets have been extensively reviewed in various contexts including comprehensive monographs; [5–17] this brief review highlights the use of electrochemical bond formations in the arena of natural products total synthesis with particular focus on completed works.…”