Hydrogen/Deuterium‐Exchange Reactions of Methane with Aromatics and Cyclohexane Catalyzed by a Nanoscopic Aluminum Chlorofluoride

H/D‐exchange reactions between methane and deuterated solvents such as [D 6 ]benzene and [D 12 ]cyclohexane were heterogeneously catalyzed by nanoscopic aluminum chlorofluoride (ACF=AlCl x F 3− x , x ≈0.05–0.3) under very mild conditions. 13 C NMR spectroscopy experiments at labeled methane revealed the formation of all isotopologues. AlCl 3 , AlBr 3 , HS‐AlF 3 , γ‐Al 2 O 3 , and γ‐Al 2 O 3 preheated at 700 °C did not show any H/D‐exchange reaction of methane or [D 6 ]benzene. Mechanistically, electrophilic activation of methane was suggested at the ACF surface.