Acid‐free and highly efficient one‐step nitration of naphthalene with NO₂ promoted by O₂‐Ac₂O in Fe‐ and Cu‐modified S₂O₈²⁻/ZrO₂ catalyst to 1,5‐dinitronaphthalene under mild conditions

It is crucial to develop an acid‐free, mild, and efficient strategy for preparing 1,5‐dinitronaphthalene (1,5‐DNN) from naphthalene (NT). This work presented a one‐step NT nitration method using NO 2 conjugated to an O 2 ‐Ac 2 O system over Fe‐/Cu‐modified S 2 O 8 2− /ZrO 2 catalyst (). The effects of different nitration systems and Fe‐/Cu‐modified ZrO 2 with various sulphur sources on NT nitration have been studied. Under optimal conditions, 99.5% of the NT conversion with 56.9% selectivity to 1,5‐DNN was obtained. Synergistic catalysis between the strong acid site and the current nitration system remarkably improved the 1,5‐DNN selectivity. The characterization results demonstrated that the appropriate Fe/Cu metals loadings combined with the covalent persulphates promoted the formation of more active tetragonal ZrO 2 . Chemical bonding of Zr 4+ with S 2 O 8 2− species allowed S 6+ more electrons to withdraw than in SO 4 2− species, which led to stronger acidity and better catalytic activity in the catalyst. Moreover, a plausible catalytic nitration reaction mechanism was proposed. The findings revealed that mild reaction conditions, combined with a solid superacid catalyst and NO 2 ‐O 2 ‐Ac 2 O system, offer significant advantages in reducing acid wastewater discharge and increasing target product selectivity.