Four Oxazine 1,2,4,5 - Salt Synthesis, Characterization, Structure Analysis And Thermodynamics Research, Theoretical Calculation And Thermal Behavior

3,6-bis(3,5-dimethylpyrazol-1-yl)-1,2,4,5-terazine(BT) was synthesized by the typical synthesied route, then BT derivatives were synthesized, the single crystals of3,6-dihydrazino-s-terazine nitrate [DHTz·2(HNO3)],3,6-dihydrazino-s-terazine DNSA salt (DHTz·DNSA·2H2O),3,6-guanidine-1,2,4,5-terazine perchlorate[DGTz·2(HGO4)] and3-guanidine-6-(3,5-dimethylpy razol-1-yl)-1,2,4,5-terazine perchlorate (BGTz·HClCO4·CH3OH) were obtained, and the structures were determined by a single-crystal X-ray diffractometer.The quantum chemical calculation using density functional theory (DFT) in the Gaussian03program has been optimized, geometries and electronics structrues of the series of the compounds were obtained. Addtionally, Frequences, NBO charges of atoms, frontier orbital energy were calculated and the relationship with the stability of the compounds were calculated.The thermal behavior of DHTz·2(HNO3). DHTz·DNSA·2H2O and DGTz-2(HClO4) were studied under a non-isothermal condition by TG/DTG and DSC methods. The method of Kissinger, Ozawa, the differential and integral method were carried out to determine their of kinetic parameters, the apparent activation energy (E) and the pre-exponential (A) in the exothermic processes of DHTz·2(HNO3), and the thermal decomposition mechanism function were obtained, entropy of activation (ΔS≠), enthalpy of activation (ΔH≠),Gibbs free energy of activation (ΔG≠) of DHTz·2(HNO3), DHTz·DNSA·2H2O and DGTz-2(HClO4) were obtained.The specific heat capacity of DGTz·2(HClO4) and DHTz·DNSA·2H2O were determined with continuous Cp mode of mircocalorimeter (Micro-DSC Ⅲ). Using the determined relationship between Cp and thermodynamic temperature T, enthalpy, entropy and Gibbs free energy of compounds in the range from283K to353K, relative to the standard temperature298.15K, were calculated by the relationship between specific heat capacity and thermodynamic functions.