Green and continuous aerobic oxidation of ethylbenzene over homogeneous and heterogeneous NHPI in a micro-packed bed reactor

Abstract

Aerobic oxidation of ethylbenzene (EB) has emerged as a promising strategy for the selective synthesis of acetophenone (AP) in line with green chemistry. The integration of flow chemistry into the pharmaceutical industry has been facilitated by recent advancements in microreactor technology. In this work, a continuous micro-packed bed reactor platform is developed to determine the kinetics of aerobic EB oxidation in the presence of N-hydroxyphthalimide (NHPI). The microreactor system offers enhanced gas–liquid mass transfer, leading to a 2-order-of-magnitude increase in the space–time yield of EB oxidation compared to traditional batch reactors. Furthermore, the organic catalyst NHPI is covalently anchored on commercial activated carbon through an imidization reaction. The synthetic heterogeneous catalysts exhibit excellent performance in terms of AP yield of 87.4 % and TOF value of 2.21 h−1 for continuous aerobic EB oxidation.