Synergistic C─N Coupling for Efficient Cyclohexanone Oxime Synthesis from Ambient Air by Supported Molecular Catalysts

This is the authors' abstract. We don't add key points for this paper.

Electrocatalytic synthesis of cyclohexanone oxime from rich nitrogen resources is a promising alternative to traditional industrial processes. However, the difficulties in unraveling atomic‐scale catalytic mechanisms and managing selective C─N coupling still pose great challenges to realizing considerable yield and selectivity, and therefore rational catalyst design to boost collaborative C─N coupling for oxime synthesis is particularly attractive. In the present work, molecular catalysts are demonstrated to be unique for oxime synthesis under mild conditions, i.e., iron bis(pyridyl)amine‐bipyridine (FeBPAbipyH) modified MWCNTs@CP (multi‐walled carbon nanotubes coated carbon fiber paper) cathodes produced cyclohexanone oxime from NO 2 − and cyclohexanone, attaining mass‐specific efficiency of 87.00 mg h −1 cm −2 mg cat −1 , Faradaic efficiency (FE) of 77.3%, and exclusive carbon selectivity, which is the best efficiency known to date in H‐cell. Mechanistic studies showed that the FeBPAbipyH molecular skeleton exhibited intimate interaction with both cyclohexanone and NO 2 − , and catalyzed selective NO 2 − ‐to‐NH 2 OH reduction for C─N bond in situ. The in‐depth understanding of substrate‐catalyst interactions and synergic C─N coupling from molecular points of view offers valuable insights to boost collaborative synthesis of organic nitrogen compounds. Further integrating plasma‐driven N 2 oxidation and electrocatalysis enabled cyclohexanone oxime formation at 61.73 mg h −1 cm −2 mg cat −1 on the FeBPAbipyH/MWCNTs@CP electrode, and the whole synthetic and separation process is projected to be profitable with a promising cost of $2709 ton −1 , which is much lower than the breakeven point (∼$10 000 ton −1 ), representing a sustainable pathway to nitrogenous chemical synthesis from abundant resources under ambient conditions.