Studies On Synthesis Of Azofurazan Derivatives And Furazantetrazine

Furazan energetic compounds usually show high density, large positive heats of formation, good thermal stability, high oxygen balance and remarkable insensitivity. They are one of the forefronts and hot areas of the energy materials on account of explosive parameters.3,4-Diaminofurazan (DAF) were synthesized from diaminoglyoxime (DAG) which was obtained using glyoxal as starting material.3,3’-diamino-4,4’-azoxyfurazan (DAOAF) was synthesized by using the oxidant potassium hydrogen persulfate salt from DAF. The mechanism of this reaction was invesitagated. Bis[4-aminofurazanyl-3-azoxy]azofurazan (ADAAF) was synthesized under the condition of KBrO3 and glacial acetic acid oxidization reaction. The mechanism and the factors on the synthesis of ADAAF were thoroughly studied. The reaction conditions were optimized and the optimum reaction conditions were found to be as follows:the reaction temperature 50 ℃, reaction time 16 h, and materials ratio (n(CH3Cooh) n(DAOAF)) was 68:1 with the yield of 58.5%. ADAAF.was nitrated with the pure nitric acid to generate bis[4-nitramino-furazanyl-3-azoxy]azofurazan (ADNAAF). Diammonium salt of ADNAAF, dihydrazinium salt of ADNAAF or diguanidinium salt of ADNAAF were prepared separately from aqueous ammonia, hydrazine and guanidine nitrate by using ADNAAF as staring material. The factors on the synthesis of diammonium salt and diguanidinium salt were thoroughly investigated.The synthesis of [1,2,5]-oxadiazole-[3,4-e]-[1,2,3,4]-tetrazine-4,6-di-N-oxide (FTDO) was optimized. FTDO was synthesized from DAF in three steps via the reactions of oxidation, condensation and cyclization.3-amino-4-nitrosofurazan (ANSF) was obtained by using the oxidant H2O2, Na2WO4 and H2SO4 from DAF.3-amino-4-(tert-butyl-NNO-azoxy)furazan was obtained from the reaction of ANSF and N,N-dibromo-tert-butylamine. FTDO was obtained by the cyclization in HNO3, H2SO4 and Ac2O system. The mechanism of cyclization was discussed and the key factors for the reaction was studied, the optimum reaction conditions were found to be as follows:the reaction time 1 h, reaction temperature 20 ℃, and materials ratio(n(HNO3): n(H2SO4)) was 1:2.The structures of these compounds were characterized by IR, NMR and MS. The thermal properties of some compounds were studied by thermogravimetry (TG) and differential scanning calorimetry (DSC) and the detonation parameters were calculated. The results show that combination of furazan ring with azo or azoxy can improve the thermal stability, nitroamino group can increase density and detonation velocity, energetic ionic salts can enhance heats of formation and thermal stability.