Gadolinium triflate immobilized in imidazolium based ionic liquids: a recyclable catalyst and green solvent for acetylation of alcohols and amines

Abstract

Gadolinium triflate immobilized in room temperature ionic liquids (RTIL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) was found to be a recyclable and green catalyst for acetylation of a variety of alcohols, phenols and amines. Acetylation reactions using acetic anhydride (Ac₂O) as the reagent proceeded in excellent yields in the presence of catalytic amounts (0.2–0.5 mol%) of Gd(OTf)₃ immobilized in RTILs, at ambient temperature. In addition, the catalyst system Gd(OTf)₃/[bmim][X] can be recovered and reused efficiently in these transformations.