Co-Mn-Ce oxide catalysts for efficient p-methoxytoluene oxidation

Developing efficient, recyclable heterogeneous catalysts for the oxidation of p-methoxytoluene (p-MT) remains a critical challenge in industrial organic synthesis. Herein, a ternary Co-Mn-Ce oxide catalyst was synthesized via co-precipitation and systematically optimized to address limitations in mass transfer and catalyst reusability. By modulating the Ce content, the structural evolution from cobalt‑manganese spinel phases to CeO 2 -dominated crystallites was demonstrated, significantly influencing catalytic performance. The CoMn 3 Ce 1.9 catalyst with high Ce loading exhibited a p-MT conversion of 95.0% under mild conditions, outperforming the low-Ce analogs, which showed only 50–60% p-MT conversion. Characterization revealed that CeO 2 -rich catalysts featured larger average pore sizes (18 nm vs. 2–4 nm for spinel-dominated systems), mitigating diffusion constraints and enhancing oxygen activation. High-concentration experiments (8 mL p-MT) maintained 77.7% conversion after 12 h, but with increased esterification to p-methoxybenzyl acetate (p-MBAc). Remarkably, the catalyst retained >70% activity over four runs. This work highlights the optimized pore architecture in overcoming traditional limitations of spinel-based catalysts, offering a sustainable, scalable strategy for aromatic aldehyde synthesis. The findings provide critical insights into designing multifunctional heterogeneous catalysts for selective C(sp 3 )-H bond activation, with broad implications for green chemical manufacturing.