Study On The Synthesis Of HMX From DADN By Green Nitrolysis

1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX) is one of the most excellent explosives applied nowadays.1,5-diacetyl-3,7-dinitro-1,3,5,7-tetrazacyclooctane(DADN) is a significant intermediate for the preparation of HMX. Presently the method of using HA as starting material to prepare HMX through DADN was widely used, which has the advantages of little by-product, high purity, safe process and so on.In this paper, a one-pot method of the preparation of DADN has been investigated by using formaldehyde and ammonia as the starting materials. DADN was obtained by condensation, acylation and nitrolysis without isolation of intermediates. Some factors to affect the yield of DADN were studied, such as the molar ratio of raw materials, condensation time, acylation time, nitrolysis temperature and nitrolysis time. The yield of DADN was improved to90.2%under optimized conditions:the molar ratio of HCHO to NH3was1:1.5, reacting for60min, acylating for25min, the molar ratio of HNO3to H2SO4was1:3, reacting for25min at18℃.Also, in order to achieve a clean synthesis process of HMX, nitrolysis of DADN in two nitration systems was investigated.Nitrolysis of DADN in N2O5-oraganic solvent systems was investigated including CH3OH, C2H5OH, CH2C12,CHC13and CH3CN, indicating that the solution of N2O5in CH3CN was the best one in five kinds of nitration systems. The results showed that the yield of HMX was34.0%in CH3CN-N2O5, and the yield of HMX was up to43.6%in AIL-CH3CN-N2O5.Nitrolysis of DADN in HNO3solvent systems was investigated.The results showed that the yield of HMX was up to86.0%in N2O5-HNO3. In addition,[Hnhm]HSO4was the most excellent one among ionic liquids used, and the yield of HMX was71.6%against43.6%with CH3CN under the optimal reaction condition:the molar ratio of [Hnhm]HSO4to DADN is0.03:1, the molar ratio of nitric acid to DADN was30:1, reacting for3h at50℃.It also showed that [Hnhm]HSO4was the best ionic liquid in this system with which yielded HMX up to90.6%under the optimal reaction condition:the molar ratio of [Hnhm]HSO4to DADN was0.03:1, the molar ratio of nitric acid to DADN was20:1, the molar ratio of N2O5to DADN was3:1, reacting for2h at45℃. In addition, ionic liquid could be recovered and reused without apparent loss of activity even after four runs.