A simple and highly efficient method for the protection of amines from their corresponding N-boc derivatives is reported. It is interesting that only 0.1 mol % of novel ionic liquid 1, 3-disulfonic acid imidazolium hydrogen sulfate {[Dsim] HSO4} can efficiently catalyze the reaction. Clean reaction, very short reaction times, high yields, easy preparation and high TOF (turn over frequency) values of the catalyst in comparison with reported catalysts are some advantages of this work.