Stability,acidity and interaction properties of [Bmim][SbF6] coupled with concentrated sulfuric acid

Ionic liquid coupled with strong acid systems presents considerable promise in some catalytic fields.In the present work,the multiple complex systems composed by 98 wt%concentrated sulfuric acid and[Bmim][SbF6]were investigated in the terms of stability,acidity and interaction properties.It was found that acidolysis of[Bmim][SbF6]occurred in the 98 wt%concentrated sulfuric acid accompanied by HF releasing and SbF6~ degrading to[SbF6-yXHSO4]y]~-.The species after acidolysis in the multiple complex systems were checked and confirmed by electrospray ionization mass spectrometry(ESI-MS),Fourier transform infrared spectroscopy(FT-IR),~1H NMR and19F NMR.Acidity increased slightly with less than 1 wt%[Bmim][SbF6]addition,while decreased with more proportion,which was determined based on the Hammett acidity functions H0,using13C NMR.The strong hydrogen bond S-O-H…F of interaction among the multiple complex systems was confirmed by molecular dynamic simulation.