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.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 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.