The oxidative halogenations of arenes in water using hydrogen peroxide and halide salts over an ionic catalyst containing sulfo group and hexafluorotitanate

An ionic compound, bis[1-methyl-3-(3′-sulfopropyl)imidazolium] hexafluorotitanate ( 1 ), was proved to be the efficient and recyclable catalyst for the oxidative halogenations of arenes in water using H 2 O 2 as the oxidant and halide salts as the halogenation sources. The mono-halogenated products were obtained selectively by this method. The synergetic catalytic effect coming from the two incorporated functionalities of SO 3 H and [TiF 6 ] 2− was manifested in 1 . The halogenation rate catalyzed by 1 was in the ranking of NaBr   ≫   NaCl   >   KI. The UV–vis and FT-IR analyses indicated that the successful formation and regeneration of the active peroxo-Ti species ( 1A ) with the aid of proton acid guaranteed the recycling uses of 1 .