Amino Modification And Structural Properties Of Several Energetic Compounds

Four compounds were obtained by modifying the amino site of energetic substances:bis（nitroguanidine）methane（BNGM）,N3,N3’-methylene-3,4-diamino furazan（NMDAF）,N-methylene-amino-nitroguanidine（MANG）,1-（1-amino-2,2-dinitrovinyl）guani dine（ADNVG）.The four compounds were characterized by their melting point,elemental analysis,infrared spectroscopy and nuclear magnetic resonance.Moreover,the single crystals of MANG and NMDAF were obtained,and the results were listed as below:MANG:C₂H₅N₅O₂,Orthorhombic,P_nn2,and its density is 1.630 g em^-3,and each structural unit contains 4 MANG molecules;NMDAF:C₅H-8N₈O₂,Orthorhombic,P_nn2,and its density is 1.583 g·cm^-3,and each structural unit contains 2 NMDAF molecules.The thermal behavior of BNGM,NMDAF,MANG and ADNVG were studied under non-isothermal condition by DSC-TG/DTG method.The thermal decomposition kinetic parameters and kinetics equations of the four compounds were calculated.The thermal decomposition kinetics equations of BNGM,NMDAF,and ADNVG were:dα/dT=1023.13/β5（1-α）[-ln（1-α）]2/3)/2exp（-2.30×105/RT）;dα/dT=1013.90/β[-ln（1-α）]-1 exp（-1.663×105/RT）;dα/dT=1025.71/β[4（1-α）3/2[-ln（1-α）]3/4]exp（-2.589×105/RT）,respectively.The specific heat capacities of BNGM,NMDAF,MANG,and ADNVG were determined with continuous Cp mode of Micro-DSC III,and the data were 251.87,245.68,164.44,and 251.27 J mol-1·K-1,respectively,then using the specific heat capacities to calculate the entropy of activation,enthalpy of activation and Gibbs free energy of four compounds.In order to evaluate the thermal safety of materials,their self-accelerating decomposition temperature were calculated to be 192.13,254.72,163.72 and 219.28℃,respectively,and the critical temperature of thermal explosion were 200.37,269.0,165.04,and 220.862 ℃,respectively.The adiabatic time-to-explosion of compounds were 252.28,14.49,4.30 and 236.324 s,respectively.The impact sensitivities were measured,and their detonation velocity calculated by the nitrogen equivalent formula were 7.581,7.281,7.931,7.528 km·s-1,and the detonation pressure were 25.20,22.73,26.82,24.03 GPa,respectively.The constant-volume combustion heat of the four compounds were determined to be 2237.71,3361.90,1523.40 and 1396.67 kJ·mol-1,respectively.According to Gass’s law,their standard molar enthalpy of combustion and standard molar enthalpy of formation were obtained,which provides more comprehensive data for the study of their thermal properties.