Aerobic oxidative cleavage of isoeugenol to vanillin over a Co(II)-porphyrin covalently grafted on hydroxyl-rich graphene oxide

Abstract Aerobic oxidation of isoeugenol to vanillin was investigated using cobalt(II) porphyrin (CoTCPP: meso-tetrakis(4-carboxy)phenyl porphyrinato cobalt(II)) covalently linked to hydroxyl-rich graphene oxide (GOOH) as a heterogeneous catalyst. The catalyst was thoroughly characterized by various spectroscopic techniques, such as Fourier transform infrared spectroscopy, powder X-ray diffraction, N2 adsorption–desorption, X-ray photoelectron spectroscopy, and scanning electron microscopy and energy-dispersive X-ray spectroscopy analytical techniques. The catalytic activity of the CoTCPP/GOOH gave an excellent yield of 75.1% in the conversion of isoeugenol to vanillin using molecular oxygen for a 20 h reaction at 100 °C in 3.0 MPa oxygen pressure. The catalyst showed exceptional stability upon multiple reuses without significant losses in activity. These findings underscore the potential of CoTCPP/GOOH as an efficient and robust heterogeneous catalyst for the efficient aerobic oxidation of biomass-derived platform chemicals into valuable end products.