Progress and perspectives on NHPI and immobilized NHPI catalysts in organocatalytic aerobic oxidation

Organic molecules have attracted attention as efficient, eco-friendly catalysts. Among them, N-hydroxyphthalimide (NHPI) and its immobilized derivatives stand out for aerobic oxidation. Their catalytic activity arises from the phthalimide N-oxyl (PINO) radical, which abstracts hydrogen to form carbon-centered radicals that undergo selective oxidation. Recent advances include NHPI combined with Fe, Cu, Ni, or Co salts, as well as hydrophobic derivatives, improving performance and recyclability. Applications span oxidation of hydrocarbons, alcohols, and polymers, with new potential in functionalizing polyethylene and polypropylene. Future directions emphasize integrating NHPI catalysis with electrochemical methods and sustainable, recyclable systems.