Fluoroanions and cations in the HF–SbF5 superacid system. A 19F and 1H NMR study

Abstract

The ionic composition of the HF–SbF₅ superacid system has been investigated by ¹H and ¹⁹F high field NMR. The anionic distribution over the whole composition range could be directly calculated from the ¹⁹F NMR spectra. The cationic distribution was then estimated on the basis of charge balance. When the concentration of SbF₅ in HF was higher than 20 mol%, increasing amounts of nonassociated SbF₅ appeared. This change in composition can be linked to the change in reactivity of the superacid system in the activation process of small alkanes.