Selective oxidation of cyclohexanol to cyclohexanone with peroxydisulfate over Co/N doped porous carbon

Abstract

Cyclohexanone serves as a vital chemical intermediate in nylon production and as a solvent in the manufacturing of resins and paints. The quest for facile, environmentally-friendly, and cost-effective methods to achieve selective oxidation of cyclohexanol is highly desirable. In this study, we successfully achieved the oxidation in water solution using peroxydisulfate (PDS) activation. This was accomplished by employing a Co/N doped porous carbon catalyst synthesized through the one-step carbonization of zeolite-imidazolate frameworks (ZIFs). The catalysts derived from ZIFs with various Co/Zn ratios were extensively characterized using XRD, SEM, TEM, N2 adsorption–desorption, and XPS techniques. The catalyst's performance was assessed under different reaction conditions, including reaction temperature, PDS dosage, and water quality. Notably, the results revealed that under mild conditions, a high efficiency was achieved with over 55% cyclohexanol conversion and 80% cyclohexanone selectivity within 3 h. To gain a greater understanding of the reactive oxygen species involved, we conducted further quenching experiments and EPR analysis. Our findings suggested that·SO4-, ·OH, and mediated electron transfer played a dominant role in the oxidation process. The insights obtained from this work have the potential to offer a green and economically viable method for the selective oxidation of cyclohexanol to cyclohexanone.