Synthesis Of4,4’-bis-1,2,4-triazole And Its Nitro Derivatives

3,3’,5,5’-Tetranitro-4,4’-bi(1,2,4-triazole) is a very important energetic material with high density (1.99g/cm3), detonation speed (9.50Km/s) and C-J pressure (41.7GPa) predicted in theory. But the related synthetic method was not reported till now.Three intermediates of3,31,5,5’-tetranitro-4,4’-bi(1,2,4-triazole) were synthesized:4,4’-bis-1,2,4-triazole, tetrabromo-4,4’-bi(1,2,4-triazole) and tetraiodo-4,4’-bi(1,2,4-triazole). These products were characterized by UV, IR,1H NMR,13C NMR, MS, HRMS, TG-DSC and element analysis. Single crystals of the three key intermediates were all cultivated by slow solvent evaporation method, crystal measurement data and the corresponding CCDC numbers were obtained.4,4’-Bis-1,2,4-triazole was synthesized by condensation from4-amine-1,2,4-triazole and N,N’-dimethylformamide azine dihydrochloride (1), which was obtained through Vilsmeier reaction from sulfurous dichloride, N,N-dimethylformamide and hydrazine hydrate. The synthetic mechanism of4,4’-bis-1,2,4-triazole were investigated, the optimal process conditions were determined as follow:n (4-amino-1,2,4-triazole):n(1)=1.2:1, reaction time8h, temperature110℃, solvent toluene. The yield of this single step was86.4%.4,4’-Bis-1,2,4-triazole was perhalogenized successfully with different halogenization agents.3,3’,5,5’-tetranitro-4,4’-bi(1,2,4-triazole) was successfully monitored and characterized by MS and HPLC-HRMS when tetraiodo-4,4’-bi(1,2,4-triazole) was nitrated4h by NO2BF4in DMSO140℃under N2protection.The synthetic mechanisms of every intermediate were also discussed in detail. Besides, the synthetic methods and experimental experience of polynitro-derivatives of4,4’-bis-1,2,4-triazole should be valuable to energetic material explorers.