First application of bismuth triflate as an efficient, non-transition metallic and reusable catalyst for aromatic nitration

Bismuth(III) triflate [Bi(OTf)3] has been found to be efficient and reusable in catalyzing the aromatic nitration using HNO3 as the direct nitrating reagent with toluene as the model substrate. In the presence of 4 mol% Bi(OTf)3, toluene could be converted entirely to nitrotoluenes with a bit excess of HNO3 within 6 h in refluxing 1,2-dichloroethane. And Bi(OTf)3 can be easily recycled five times without loss of activity. The nitration protocol is both economical and environmentally friendly.

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► Bi(OTf)3 was first applied in catalyzing the aromatic nitration.
► High efficiency was exhibited in toluene nitration.
► Nitric acid and toluene can be reacted entirely, respectively.
► The catalytic activity was superior to the reported transition metal triflates.
► Bi(OTf)3 could be recycled and reused.