Esterification of alcohols by acetic acid has been carried out at room temperature in a group of Bronsted acidic ionic liquids derived from protophilic amides. Good conversion ratio and excellent reaction rate are obtained, and the liquid esters formed a separate phase that is decanted without containing ionic liquid in it. The possible reason of faster and more efficient esterification is: by stabilizing the protonated acetic acid and limiting the alcohol protonation, protophilic amide ionic liquid (PAIL) accelerates the reaction. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.