6-(3,5-二甲基-1H-吡唑)-1,2,4,5-四嗪-3-酮(DPTzO)及其胍盐的晶体结构和热分解行为

Crystal Structure and Thermal Decomposition Behaviors of 6-(3,5-Dimethyl-1H- pyrazole)-1,2,4,5-tetrazin-3-one (DPTzO) and Its Guanidine Salt

合成了两种四嗪衍生物6-(3,5-二甲基-1H-吡唑)-1,2,4,5-四嗪-3-酮(DPTzO)及其胍盐(G·DPTzO),采用红外光谱(FT-IR)、元素分析(EA)、核磁共振(NMR)和X-射线单晶衍射对结构进行表征;利用差示扫描量热法(DSC)和热重法(TG-DTG)分析两种化合物的热分解行为;根据不同升温速率下的DSC曲线用Kissinger和Ozawa法计算热分解动力学参数。结果表明,DPTzO晶体属于正交晶系,Pna 2 1空间群,晶胞参数为:a=1.224 7(2)nm,b=1.310 9(3)nm,c=0.529 88(10)nm,α=90°,β=90°,γ=90°,V=0.850 7(3)nm,Z=4;G·DPTzO晶体属于单斜晶系,P2 1/c空间群,晶胞参数为a=0.754 30(13)nm,b=0.923 52(17)nm,c=1.763 7(3)nm,α=90°,β=100.754(3)°,γ=90°,V=1.207(4)nm 3,Z=4;G·DPTzO中G+与DPTzO-上N、O原子形成大量氢键构成二维结构。DPTzO与G·DPTzO的活化能(E)和指前因子(A)分别为210.60和237.77 kJ/mol、10 21.2和10 21.0 s-1;自加速分解温度(T SADT)、热点火温度(T be)和热爆炸临界温度(T bp)分别为204.49和268.57℃、202.99和260.21℃、205.80和264.35℃,分子间氢键的存在提高了胍盐的热安定性。

6-(3,5-Dimethyl-1H-pyrazole)-1,2,4,5-tetrazin-3-one(DPTzO)and its guanidine salt(G·DPTzO)were synthesized and characterized by Fourier-transform infrared spectroscopy(FT-IR),elemental analysis(EA),nuclear magnetic resonance(NMR)and single crystal X-ray diffraction.The thermal decomposition behaviors of the two compounds were analyzed by thermogravimetry(TG-DTG)and differential scanning calorimetry(DSC)under non-isothermal conditions and then the thermal decomposition kinetic parameters were calculated by the Kissinger and Ozawa′s methods.The crystal parameters are determined as follows:DPTzO,orthorhombic,space group Pna 2 1,a=1.224 7(2)nm,b=1.310 9(3)nm,c=0.529 88(10)nm,α=90°,β=90°,γ=90°,V=0.850 7(3)nm,Z=4;G·DPTzO,monoclinic,space group P2 1/c,a=0.754 30(13)nm,b=0.923 52(17)nm,c=1.763 7(3)nm,α=90°,β=100.754(3)°,γ=90°,V=1.207(4)nm 3,Z=4.In G·DPTzO,hydrogen bonds between G+and the N,O atoms on the DPTzO-group connect the molecules into a two-dimentional structure.The apparent activation energy(E)and pre-exponential constant(A)of the thermal decomposition were determined as 210.60 kJ/mol and 10 21.2 s-1 for DPTzO and 237.77 kJ/mol and 10 21.0 s-1 for G·DPTzO,respectively.The self-accelerating decomposition temperature(T SADT),the thermal ignition temperature(T be)and the critical thermal explosion temperature(T bp)are 204.49 and 268.57℃,202.99 and 260.21℃,205.80 and 264.35℃,respectively.The intermolecular hydrogen bonds are helpful for enhancing the thermal stability of guanidine salt.