SO42−/ZrO2–titania nanotubes as efficient solid superacid catalysts for selective mononitration of toluene

Abstract

SO42 −/ZrO2–titania nanotubes–X (SO42 −/ZrO2–TNTs–X; X of Ti/Zr) solid superacid catalysts with different atom ratios (Ti/Zr) were successfully prepared. The SO42 −/ZrO2–TNTs–2 (Ti/Zr of 2) have a specific surface area of 394 m2/g and an acid intensity of 1.839 mmol/g. The SO42 −/ZrO2–TNTs–2 show excellent selectivity (p/o of 3.34) and activity (yield of 98%) in the selective mononitration of toluene. Importantly, the SO42 −/ZrO2–TNTs–2 can be efficiently recycled and regenerated by simple sulfuric acid soaking.