Synthesis Of Several Kinds Of Heat Resistant Energetic Compounds Based On TNB

Heat-resistant explosives are a kind of important energetic materials, which are used in the environment of high temperature and pressure such as space, deep sea and underground. According to the requirements of green chemistry, it is the hotspot of current research of heat-resistant explosives that improves the existing synthesis process to reduce environmental pollution and cost. On the other hand, it is also the hot topic that designs better properties of new heat-resistant energetic compounds to provide more alternatives for the application of them.HNS is a kind of heat-resistant explosives while HNBB is the synthetic intermediate of HNS. They are both the compounds basing on TNB coupled via-CH2-CH2-and-CH=CH-, respectively. The benzene and bromine of using in the original synthetic process of HNBB and HNS have toxicity and corrosivity, so it is significant to improve the synthetic process of HNBB and HNS. FOX-7 is a novel insensitive explosives with high energy. TFT can be obtained by condensation reaction of amino groups and 2,4,6-trinitrochlorobenzene, which is a new energetic compounds basing on connecting of TNB and FOX-7.HNBB was synthesized by oxidizing and coupling TNT using sodium hypochlorite with ethanol as single solvent. The optimal conditions were obtained by optimizing the process. The pH of sodium hypochlorite solution was 12.7, the ratio of TNT and NaCIO was 4.4 mmol: 4 mL, the time was 1 h and the temperature was 55℃. The productin was purified by ethanol/ethyl acetate with the yield of 80.0%.HNS was synthesized by oxidizing HNBB using FeCl2TEMPO and sodium stearate with DMSO as solvent and the sodium stearate was used to promote the dissolution of FeCl2 in the solvent. The optimal conditions were obtained by optimizing the process. The ratio of HNBB, TEMPO, FeCl2·4H2O, C17H35COONa, and DMSO was 2.2 mmol:0.13 mmol:0.15 mmol:0.13 mmol:10 mL, the reaction time was 5 h and the temperature was 55℃. The production was purified by acetone and HNO3 with the yield of 73%.TFT was synthesized by 2,4-dinitrochlorobenzene and FOX-7 as raw materials. The nitration conditions were optimized. The yield of 2,4,6-trinitrochlorobenzene was 82.5% when the temperature was 130℃℃ and the volume ratio of HNO3 and H2SO4 was 1:3.5. The major factors of condensation process were also discussed. The yield of production was 76% when KF and imidazole were added to the reaction system, the temperature was 78℃ and the reaction time was 6 h. Its thermal stability was analyzed by DSC and the decomposition temperature was 331.3℃, which indicated that its thermal stability was better than that of FOX-7.The density and detonation velocity of TFT are 1.85 g/cm3 and 8.83 km/s, which is higher than PYX and HNS and close to FOX-7. The detonation pressure and hso are 36.25 GPa and 156 cm, which is higher than HNS, PYX and FOX-7. 1,2-dinitro-1,2-bis(2,4,6-trinitrophenyl)ethene is designed based on the structure of HNS and its correlation properties are calculated. The density, detonation heat, detonation velocity, detonation pressure and h50 are 1.81 g/cm3,1853.61 J/g,8.39 km/s31.38 GPa and 22 cm. The value of hso is lower than HNS and other properties are higher than HNS.