The Rasearch On Purity Analysis Methods Of Two New Low-Sensitivity High-Energy Explosives

Low-sensitivity high-energetic explosives have the obvious advantages of low sensitivity and high energy,which are most promising explosives in recent years.They have important applications in military weapons,civil industries and space explorations.At present,some low-sensitive and high-energetic explosives have been designed and synthesized.Among them,1,1'-diamino-4,4',5,5'-tetranitro-2,2'-biimidazole(DATNBI)and 2,4,8,10-tetranitrobenzopyrido-1,3a,6,6a-tetraazapentalene(BPTAP)have good safety performance and high energy,which are regarded to have importantly potential applications.To develop quality analysis method is important for quality control of DATNBI and BPTAP during their development and production process.The analytical methods of high performance liquid chromatography(HPLC)and high resolution mass spectrometry(HRMS)have several advantages including high sensitivity,good reproducibility,accuracy and reliability,so they are widely used for quality control of organic materials.This work is based on high performance liquid chromatography combined with high resolution mass spectrometry to develop new methods of quality analysis for DATNBI and BPTAP,which are as follows:(1)We studied the HPLC method for purity analysis of DATNBI,including the optimization of chromatographic conditions and method validation of HPLC method,real applications of DATNBI samples.The precision,stability,repeatability of HPLC method were investigated to examine the detecting performance of HPLC method.The method was based on a Phenyl-Hexyl column(4.6×150 mm,3.5 m)with acetonitrile-water mixture(containing 0.2mg·m L^-1 ammonium acetate)as mobile phase.The detection wavelength was set at 230 nm in gradient elution mode.The retention time of the method for DATNBI was 10.37 min.The separation degree of each chromatographic peak was greater than 2.10,and the tailing factor was between 0.84 and 1.38.At the same time,the method has good accuracy,precision,stability and robustness for the analysis of DATNBI.The method has a good linear response(R²=0.9995)from 1.0 to 200?g·m L^-1 toward DATNBI.The limit of detection and the limit of quantification were 0.05?g·m L^-1 and 0.13?g·m L^-1,respectively.In addition,the method was also used for the analysis of real samples of DATNBI,and the analysis results showed that the multiple recrystallization can effectively improved the purity of DATNBI,and therefore it effectively guides the purity control of DATNBI during the recrystallization process.(2)We studied the HPLC method for purity analysis of BPTAP,including the optimization of chromatographic conditions and method validation of HPLC method,real applications of BPTAP samples.Chromatographic conditions including chromatographic column,flow rate,and injection volume were investigated to improve the separation of BPTAP.The method was based on a Plus C18 column(4.6×150 mm,5.0?m)with acetonitrile-water mixture(containing 0.1 mg·m L^-1 ammonium acetate)as mobile phase.The detection wavelength was set at 230 nm in gradient elution mode.Under this analysis method,the retention time of BPTAP was 9.13 min,and the separation degree of each peak was greater than1.90,which indicated that the separation effect was good.At the same time,this method has good accuracy,precision,stability and durability for the analysis of BPTAP.When the concentration of BPTAP was range from 0.5 to 200?g·m L^-1,the chromatographic method showed a good linear response with the correlation coefficient(R²)of 0.9997.The limit of detection and the limit of quantification were 0.02?g·m L^-1 and 0.07?g·m L^-1,respectively.In addition,the method was also used to detect the purity of BPTAP during the process of recrystallization.These results show that the method has a good application prospect for purity analysis and quality control of BPTAP.(3)In order to meet the requirements of impurities identification of BPTAP,we used high performance liquid chromatography with high resolution mass spectrometry(HPLC-MS)to develop new analysis method.Meanwhile,the effects of the impurities on the purity,thermal properties and morphology of BPTAP were studied by combing with other analytical techniques.Firstly,the solubility of BPTAP in common solvents were investigated by HPLC,and thus the recrystallization of BPTAP studied in different solvents to improve the purity of BPTAP.Then,the possible impurities under different purities of BPTAP were analyzed by HRMS technique,and the chemical structures of the corresponding impurities were proposed.In addition,Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),differential scanning calorimetry(DSC)and thermogravimetry(TG)were used to study the effects of different purities on morphology and thermal properties of BPTAP.