Selective cyclohexane oxidation enhancement by electronic structures regulation of metal-poly(ionic liquid)s

Abstract

Poly(ionic liquids) (PILs) combined with the macromolecular structure and unique properties of ionic liquids show unlimited potential in catalysis. In this work, a series of metal-based PIL with different ionic ratios were prepared for the selective oxidation of cyclohexane. Characterization analysis reveals that different degrees of ionization could adjust the Co–N sites of the catalysts efficiently, leading to significant changes in their electronic structure, which strongly relate to catalytic performance in oxidation. 20.07% cyclohexane conversion and 13.06% cyclohexanone and cyclohexanol (KA oil) yield can be achieved by metal-based PILs that are better than other commercial catalysts. Compared with CoCl2, metal-based PILs perform well, with superior conversion and KA oil yield. More interestingly, the catalyst created in this study features a malleable Co–N site, which may potentially have an impact on how oxygen species adsorb and desorb from the catalyst. Therefore, the catalyst studied in this work is used as molecular oxygen for the selective oxidation of cyclohexane to produce KA oil, and its application prospect is promising.

Keywords

• Metal-PILs
• Cyclohexane oxidation
• C–H activation
• Co–N sites