Synthesis,Characterization And Properties Of Derivatives Of Five Triazine Energetic Compounds

Triazine compounds are a kind of high-nitrogen compounds with a stable molecular structure,high nitrogen content,and most of the combustion products are N₂,which is less harmful to the environment.It can store and release a large amount of energy through intramolecular ring tension,which is ideal high-energy insensitive energetic compounds..In this paper,cyanuric chloride was used as the precursor to synthesize five triazine energetic compounds:2,4,6-tris（2-（2,4-dinitrophenyl）hydrazino）-1,3,5-triazine（TDNPHT）,2,4,6-trihydrazinyl-1,3,5-triazine（THDT）,2,4,6-trihydrazinyl-1,3,5-triazine nitrate（THDT·HNO₃）,2,4,6trihydrazinyl-1,3,5-triazine perchlorate（THDT·HClO₄）and 2,4,6-tris（5-aminotetrazole）-1,3,5-triazine（TATT）.Five compounds was characterized by EA,IR and NMR.The TDNPHT single crystal containing one DMSO solvent molecule was obtained by slow solvent evaporation method.The molecular formula is C₂₃H₂₁N₁₅O₁₃S,monoclinic system,space group C 2/c,and a unit cell includes 8 molecules.The structures of five compounds were optimized on the basis set level of DFT/B3LYP 6-31G（d）,and the optimized structure parameters,the front-line orbit,mulliken charge,and molecular surface electrostatic potential were analyzed.The thermal behavior of five compounds was analyzed by DSC and TG methods.Under the condition of 10℃·min^-1,TDNPHT,THDT and TATT have only one exothermic decomposition stage,and their peak temperatures（T_p）were 280.42,342.09,and 324.21℃,respectively.The nitrate and perchlorate of THDT are both have two exothermic stages,the T_p of first stage were 246.06 and 268.32℃.The thermal stability sequence is THDT>TATT>TDNPHT>THDT·HNO₃>THDT·HClO₄.Integral method,Ozawa method and Kissinger method are used to calculate their thermal decomposition equations by kinetic calculation.The specific heat equations of TDNPHT,THDT,THDT·HNO₃,THDT·HClO₄ and TATT were measured by Micro-DSCIII microcalorimeter,and the molar heat capacities were calculated to be 738.38,234.95,336.26,323.69 and 370.79 J·mol^-1,respectively.Then,the entropy of activation(H_T-H_298.15),enthalpy of activation(S_T-S_298.15),and Gibbs free energy(G_T-G_298.15)were calculated according to the specific heat capacity equation in the temperature range of 283～333 K.In order to evaluate the thermal safety of these five compounds,their T_SADT and T_b were calculated.Their stability was consistent with the DSC measurement results.The constant-volume combustion heat of TDNPHT、THDT and TATT were measured with an oxygen bomb calorimeter,and the standard molar enthalpy of formation was calculated to be 3364.20,201.285 and 901.61 k J·mol^-1,respectively.The impact sensitivities were measured,the detonation velocities of the five substances calculated by the modified nitrogen equivalent method were 6.096,6.974,7.307,7.385 and7.171 km·s^-1,respectively,and the detonation pressure are 16.01,20.76,22.99,23.74 and 22.42GPa,respectively.THDT·HClO₄ exhibits the best detonation performance.The impact sensitivities of five compounds were measured,and the impact sensitivities were>7.84,>23.52,>13.72,>11.76 and>23.52 J,respectively.The results show that all five compounds are relatively insensitive.