Synthesis and thermal behaviors of 4-amino-3,5-dinitro-1H-pyrazole

摘要

4-Amino-3,5-dinitro-1H-pyrazole (LLM-116) was synthesized by vicarious nucleophilic substitution (VNS) reaction, and its structure was characterized by NMR, IR and element analysis. The thermal decomposition kinetics and mechanism were studied by means of different heating rate differential scanning calorimetry (DSC), thermolysis in situ rapid-scan FTIR and simultaneous TG-MS technology. The results show that the apparent activation energy and pre-exponential factor of the exothermic decomposition reaction of LLM-116 obtained by Kissinger method are 106.97 kJ mol~(-1), 10~(10.47) s~(-1) in first decomposition stage and 138.98 kj mol~(-1), 10~(12.24) s~(-1) in second decomposition stage. The decomposition of LLM-116 begins with one molecular water lost by -NO_2 and -NH_2 forming furazan in the LLM-116 structure. The furazan compound is unstable to generate NO. At the same time, another NO molecular is released as -O-NO is broken at approximately 173 C in the first stage, and then HCN and unsaturated poly hydrocarbon are produced as pyrazole decomposes at 236 C in the second stage. The above-mentioned information on thermal behavior is quite useful for analyzing and evaluating the stability and thermal safety of LLM-116.