Study On The Synthesis Of Two Diazobenzene Nitro Derivatives

Due to the presence of nitro and diazo groups,diazobenzene nitro compounds generally contain higher energy and density,and are mainly used as explosives.At present,there are relatively few studies on diazobenzene nitro compounds.This paper explores the synthesis of nitrobenzene nitro derivatives and the study of the thermal decomposition properties aim to develop energetic compounds with higher energy levels.In this paper,4-chloro-3,5-dinitroaniline was used as raw material to synthesize two diazobenzene nitro derivatives of 6-diazo-3,5-dichloro-2,4-dinitrophenol and 4-diazo-2,6-dinitrophenol through two routes.A series of synthesized substances are characterized by melting point apparatus,thin layer chromatography,Fourier infrared spectroscopy,nuclear magnetic resonance,elemental analysis,and x-ray single crystal diffraction,and the structures of each compound are determined.Calculate the detonation parameters of two diazobenzene nitro derivatives,and confirm by comparison that 4-diazo-2,6-dinitrophenol has better detonation performance.Therefore,differential scanning calorimeter(DSC)and accelerating rate calorimeter(ARC)are used to study the thermal properties of 4-diazo-2,6-dinitrophenol.Using 4-chloro-3,5-dinitroaniline as raw material,acetylation in acetic anhydride system to synthesize 4-chloro-3,5-dinitroacetanilide.The best process for synthesizing the substance through single factor experiments is: m(4-chloro-3,5-dinitroaniline): V(acetic anhydride)=1:10,V(acetic anhydride): V(distilled water)= 1:2,reaction temperature is 120 °C,reaction time is 2 h,the yield is 92.2%;Using 4-chloro-3,5-dinitroacetanilide as raw material,in the nitrosulfur mixed acid system,4-chloro-1-nitroamino-2,3,5,6-tetranitrobenzene is synthesized by nitration.The best process for synthesizing this substance through single factor experiment is: n(4-chloro-3,5-dinitroacetanilide): n(fuming nitric acid)= 1:10,m(fuming nitric acid): m(concentrated sulfuric acid)= 1:12,reaction temperature is 30 °C,reaction time is 2 h,the yield is 85.1%;Using 4-chloro-1-nitroamino-2,3,5,6-tetranitrobenzene as raw material,it reacts with sodium dichloroisocyanurate(SDCI)to synthesize 6-diazo-3,5-dichloro-2,4-dinitrophenol.The best process to synthesize this substance through single factor experiment is: m(4-chloro-1-nitroamino-2,3,5,6-tetranitrobenzene): V(acetonitrile)= 1:20,n(4-chloro-1-nitroamino-2,3,5,6-tetranitrobenzene): n(SDCI)= 1:1.5,reaction temperature is-10 °C,reaction time is 2h,the yield is 28.2%.Using 4-chloro-3,5-dinitroaniline as a raw material,4-diazo-2,6-dinitrophenol is synthesized under the reflux conditions of fuming nitric acid.Through single factor experiments,the best process for synthesizing the substance is: n(4-chloro-3,5-dinitroaniline): n(fuming nitric acid)= 1:100,reaction temperature is 65°C,reaction time is 2h,the yield is 66.3%.According to the modified nitrogen equivalent formula and the Kamlet formula,the detonation velocity and detonation pressure of the two diazobenzene nitro derivatives are calculated.The detonation velocities of 6-diazo-3,5-dichloro-2,4-dinitrophenol are 7182m·s-1and 6949m·s-1,respectively,and the detonation pressures are 23.80GPa and 23.42GPa,respectively.The detonation velocities of 4-diazo-2,6-dinitrophenol are 8084 m·s-1 and 7800m·s-1,respectively,and the detonation pressures are 29.61 GPa and 27.85 GPa,respectively.By comparison,it is found that the detonation ability of 4-diazo-2,6-dinitrophenol is stronger.The thermal decomposition behavior of 4-diazo-2,6-dinitrophenol was studied by using DSC and ARC technology,and the thermal decomposition kinetic parameters of the substance were calculated,which provided more reference data for the next study of the substance.