The nucleophilic substitution of PhCCl3 by KF in imidazolium-type RTILs is faster than in classical organic solvents but it is strongly dependent upon the nature of the counteranion. The addition of bromide salts in substoichoimetric amounts to the [bmim][PF6] solvent strongly accelerates this reaction. Furthermore, it has been discovered that addition of KPF6 to the reaction mixtures strongly activates the nucleophilic fluorination by KF, not only in the [bmim][NTf2] or [bmim][PF6] ionic liquids but also for the reactions performed in sulfolane.
