Use of energetic plasticizer, N-Butyl-N-(2-Nitroxyethyl) Nitramine (BuNENA), in the propellants’ formulations, has some advantages such as not migration in the fuel, high thermal stability, low sensitivity of the propellant formulation, improvement in mechanical properties and raising the impulse due to light molecular weight of combustion gases. In this study two acidic ionic liquids ([(Ph)₃P(CH₂)₄SO₃H][PTSA] and [(Ph)₃P(CH₂)₄SO₃H][HSO₄]) were synthesized, characterized and used in the synthesis of BuNENA energetic plasticizer, as green and reusable catalysts. These catalysts have efficiently catalyzed the synthesis reaction of BuNENA via the nitration of n-butyl ethanol amine in the presence of nitric acid 65% or nitric acid 100%. Use of these ionic liquids in the synthesis of BuNENA has some benefits such as high yield of the product, short reaction time, use of green, non corrosive, non toxic and reusable catalyst and finally economic procedure.