Selective Oxygen Oxidation of <i>o</i> -Cresol to 2-Methyl-1,4-Benzoquinone in a Microreactor with Co-Salophen as Catalyst

Methyl-1,4-benzoquinone (2-MBQ) is a valuable quinone compound with extensive applications in pharmaceuticals, materials science, and fine chemicals. In this study, the aerobic oxidation of o-cresol to 2-MBQ, using oxygen as the oxidant, was optimized by comparing two Co-Schiff base catalysts, Co-salophen and Co-salen, to identify the most efficient catalytic system. A continuous-flow microreactor was then employed to further enhance the reaction process, leveraging its superior gas–liquid mass transfer and precise control over the reaction parameters. Under optimized conditions, the microreactor achieved 99% o-cresol conversion and 87% 2-MBQ yield within 50 min, significantly outperforming the traditional batch reactor, which required 180 min to achieve 98% conversion and only 82% yield. Kinetic studies revealed that the reaction follows a second-order kinetic model, with an activation energy of 24.45 kJ/mol for the synthesis of 2-MBQ from o-cresol. These results highlight the advantages of microreactors in accelerating reaction time and improving product selectivity, providing valuable insights for the synthesis of 2-MBQ and the application of microreactors in chemical processes.