Beckmann Rearrangement with Improved Atom Economy, Catalyzed by Inexpensive, Reusable, Bro̷nsted Acidic Ionic Liquid

Inexpensive protic ionic liquids, synthesized from di- or triamines and excess sulfuric acid, were used as solvents catalysts for the Beckmann rearrangement. The use of liquids in place oleum acid allowed base neutralization step, which is required conventional rearrangement, to be entirely avoided, thereby dramatically improving atom economy. Using a biphasic water/organic solvent extraction system, it was possible recover reuse liquid. proposed method found applicable synthesis range primary secondary amides.