Polygonal mesopores microflower catalysts for the catalytic oxidation of 2-nitro-4-methylsulfonyltoluene to 2-nitro-4-methylsulfonylbenzoic acid in a continuous-flow microreactor

• FeOOH/Fe3O4/MOF polygonal mesopores microflower catalyst synthesized via room-temperature templating from MIL-88B(Fe) exhibits high catalytic activity for NMST oxidation to NMSBA using oxygen as a clean oxidant. • The continuous-flow microreactor system significantly accelerates reaction rate, shortens reaction time, and enhances selectivity compared to traditional batch reactors. • The sustainable protocol uses an inexpensive and environmentally friendly NaOH/methanol mixture, enabling gram-scale preparation of carboxylic acid and benzyl alcohol derivatives with high chemoselectivities. • The approach offers a green alternative to conventional strong oxidants, reducing environmental pollution and holding potential for industrial applications.