Abstract
Aromatics nitrate with NO2/air catalyzed by novel Brønsted acidic ionic liquids (ILs) without any volatile chlorinated organic solvent under mild conditions. The ILs employed were caprolactam based, [Caprolactam]X (X−=pTSO−, BSO−, BF4 −, NO3 −), which are of relatively lower cost and lower toxicity than traditional imidazolium‐based ILs. The nitration reactions were carried out at −15 to −0°C first, then at room temperature for a longer time with a little excessive NO2 (ca. 1.4 eqv.) for moderate yield (for toluene). The IL could be reused four times.