Four Triazine Class Of Energetic Compounds In Synthesis, Quantum Chemistry Calculation, Thermal Behavior And Non-isothermal Decomposition Kinetics

Eight kinds of tetrazine derivates were synthesized in two different ways. They are 3,6-dibenzyl-S-terazine (DBT),3,6-bis(3-pyridyl)-S-terazine (BPT),3,6-bis(3,5-dimethylpyrazol-1-yl)-S-terazine (BT),3,6-dihydrazino-S-terazine (DHT),3,6-bis-nitroguanyl-S-tetrazin dehydrate (DNGTz·2H2O),3,6-bis(benzylmethylene)hydrazone-S-tetrazi (BBHT),3,6-bis [(4-pyridyl)methylene]hydrazone-S-tetrazine(BPHT) and 3,6-bis[(4-nitrophenyl)methylene] hydrazone-S-tetrazine(BNHT). Particularly BBHT, BPHT and BNHT were first synthesized. All compounds were chaaracterized by elemental analysis, IR spectroscopy and NMR.The Density-Function Theory (DFT) of Gaussian03 software was used to calculate geometries and frequencies of the series of the compounds. The optimized geometry, vibration frequency and frontier orbital energy were obtained. Additionally, Nature Bond Orbital (NBO) charges of atoms were calculated, and the relationship with the stability of the compound was discussed.The DSC, TG/DTG techniques were used to study the thermal behavior of DBT, BPT, BBHT, BPHT and BNHT under a non-isothermal condition. The Kissinger method, Ozawa method, the differential method and the integral method were carried out to determine the kinetic parameters, the apparent activation energy (E) and the pre-exponential (A) of DBT and BPT in the exothermic processes. The thermal decomposition mechanism function, the critical temperature of thermal explosion (Tb), the entropy of activation (AS≠), enthalpy of activation (ΔH≠) and Gibbs free energy of activation (ΔG≠) were obtained. The temperature-resistant regularity of the compounds was also discussed.The specific heat capacity of DBT, BPT, DHTz and BNHT were determined with continuous Cp mode of mirco-calorimeter (Micro-DSCⅢ). Using the determined relationship between Cp and thermodynamic temperature T, enthalpy, entropy and Gibbs free energy of compounds in the range from 283 K to 353 K, relative to the standard temperature 298.15 K, were calculated by the relationship between specific heat capacity and thermodynamic functions.