Green catalytic oxidation of 4-ethyltoluene to 4-methylacetophenone over modified flake micro-mesoporous TS-1 zeolite supported cobalt catalysts

The development of efficient catalyst for the green oxidation of 4-ethyltoluene is crucial for addressing the synthesis technology of 4-Methylacetophenone. In this paper, cobalt oxide was loaded on continuously modified flake micro-mesoporous TS-1 (FL-TS-1) zeolite by impregnation method. In a batch reactor at 60 °C, 4-ethyltoluene was oxidized using 30 wt% hydrogen peroxide (H₂O₂) with acetic acid as the solvent and potassium bromide as an additive. Due to the active species and shape selectivity of the catalyst, the secondary carbon atom of the ethyl group on the side chain of 4-ethyltoluene is selectively catalyzed to form the main product 4-methylacetophenone. A comprehensive investigation was conducted on the influence of various parameters on the reaction. The results showed that the FL-TS-1-TPAOH@T + S catalyst with 5 wt% cobalt loading exhibited optimal reaction activity. The morphology, pore structure and surface elements of the samples were characterized and analyzed utilizing X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV–Vis), nitrogen adsorption, and X-ray photoelectron spectroscopy (XPS). The reaction mechanism and free radical processes were discussed based on the reaction activity data.