High-entropy oxide-derived Cu catalysts for the coupling reaction of cyclohexanol dehydrogenation with acetone hydrogenation

Dehydrogenation of cyclohexanol to cyclohexanone is a vital step in manufacturing nylon; however, this endothermic reaction is unfavourable at low temperatures. In this work, a high-entropy oxide (Cu0.75Zn0.15Mg7.1Al1Sc1O11-HEO) was synthesized from a well-structured Cu0.75Zn0.15Mg7.1Al1Sc1(OH)20CO3 layered double hydroxide. Characterization results disclosed that Cu0.75Zn0.15Mg7.1Al1Sc1O11-HEO possesses a large specific surface area (157 m2 g−1), enhanced basicity and high Cu dispersion in the framework of HEO (74.0%). The reduced Cu0.75Zn0.15Mg7.1Al1Sc1O11-HEO catalyst was highly active and stable in the dehydrogenation of cyclohexanol compared with Cu-based catalysts prepared using binary, ternary, and quaternary mixed metal oxides. More interestingly, the conversion of cyclohexanol could be enhanced when acetone was used as the solvent and/or hydrogen acceptor. Thus, it was confirmed that the addition of acetone can enhance the yield of cyclohexanone and simultaneously result in the hydrogenation of acetone to isopropanol.