Study On The Process Of Nitrolysis TAT To HMX With N₂O₅/HNO₃

1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX)has the best overall performance in single-quality explosives, with wide applications in military field.1,3,5,7-tetraacyl-1,3,5,7-tetraazacyclooctane (TAT) is an important intermediate for preparation of HMX. With the advantage of cheap raw materials, simple operation, mid reaction and high yields, the method of nitrolysis TAT to HMX is the most promising way to replace Bachmann method in producing HMX.With the mixture of nitric acid and dinitrogen pentoxide as a novel nitrating agent, the preparation of nitrolysis TAT to HMX was studied in this paper. The effects of various parameters, such as reaction temperature, reaction time, the amount of nitric acid and the quantity of dinitrogen pentoxide were investigated. The yield of HMX was 90.3% under the optimal reaction conditions with the mass ratio 10:1 of nitric acid to TAT and the mass ratio 2:1 of N2O5 to TAT for 75 min at 50℃. In this article, the mechanism of nitrolysis TAT to HMX was studied with synthesizing the key intermediates:1,5-diacetyl-3,7-dinitro-1,3,5,7-tetraazacyclooctane(DADN) and 1-acetyl-3,5,7-trinitro-1,3,5,7-tetraazacyclooctane(SEX).A series of imidazolium, pyridinium, triethylamine, caprolactam and PEG load imidazolium cation-based ionic liquids were synthesized. The ionic liquids were used as catalyst in nitrolysis TAT to HMX. The factors were investigated, including the amount of catalyst and variety of ionic liquids. The yield of HMX was 95% under the optimal reaction conditions:in the presence of ionic liquid [(CH2)4SO3HMim]HSO4 as catalyst, the molar ratio 1:25 of [(CH2)4SO3HMim]HSO4 to TAT, the mass ratio 10:1 of nitric acid to TAT, the mass ratio 2:1 of N2O5 to TAT, reacting for 75 min at 50℃. In addition, the ionic liquid [Et3NH]NO3, [(CH2)4SO3HPy]HSO4 also showed good catalytic activity. Ionic liquid could be conveniently separated by vacuum distillation and reused for times with good catalytic activity.