Study On Synthetic Process Of RDX

Cyclotrimethylene trinitramine (RDX) is an important explosive of high energy, and it obtained widely application in military fields. With the mixture of nitric acid and dinitrogen pentoxide as a novel nitrating agent, the experimental study of the synthesis of RDX by nitrolysis of hexamethylenetetramine (HA) was carried out. The reaction mechanism was also discussed. The effects of various parameters, such as reaction temperature, reaction time, the amount of dinitrogen pentoxide and the quantity of nitric acid were investigated, The yield of RDX was 81.1% under the optimal reaction conditions with the mass ratio 10:1 of nitric acid to HA and the mass ratio 2:1 of HA to N₂O₅ for 60 min at 0℃.A series of imidazolium, pyridinium and triethylamine cation-based ionic liquids were designed and synthesized as catalyst. The ionic liquids were characterized by ¹H NMR and IR. Reaction conditions which effect on the technology of nitrolysis of HA to synthesize RDX with N₂O₅/HNO₃ as nitrating agent catalyzed by ionic liquid were investigated, including the amount of catalyst and nitrating agent, reaction time and reaction temperature, different ionic liquids and so on. The results indicated that the yield of RDX was 85.4% under the optimal reaction conditions which were those:in the presence of ionic liquid [Bmim]BF4 as catalyst, the molar ratio 1:20 of [Bmim]BF4 to HA, the mass ratio 9:1 of nitric acid to HA, the mass ratio 2:1 of HA to N₂O₅, reacting for 60 min at 0℃. Moreover, ionic liquid [Hmim]HSO₄ and [SO₃H(CH₂)₄Py]NO₃ also showed good catalytic activity. Ionic liquid could be conveniently separated by vacuum distillation and reused for 10 times with good catalytic activity.