1,4-二氨基-3,6-二硝基吡唑[4,3-c]并吡唑的合成、热性能及量子化学研究

Synthesis, Thermal Performance and Quantum Chemistry Study on 1,4-Diamino-3,6-dinitropyrazolo[4,3-c]pyrazole

以自制的3,5-二甲基-4-氨基吡唑为原料,经重氮化、环化、硝化、氧化、脱羧硝化以及N-胺化等反应合成了1,4-二氨基-3,6-二硝基吡唑[4,3-c]并吡唑(LLM-119),采用红外光谱、核磁共振、质谱及元素分析等手段表征了中间体及目标物的结构;对4-重氮基-3,5-二甲基吡唑内盐的后处理方法进行了改进,采用冷冻结晶法代替萃取法,避免大量使用有机试剂,简化操作过程,收率由77.0%提高到86.1%;初步探讨了N-胺化反应的机理,从理论上分析了收率偏低的原因;利用DSC,TG等热分析手段研究了LLM-119的热性能,其热分解峰温为232.05℃,表明LLM-119具有较好的热稳定性;首次采用B3LYP方法,在6-31G(d,p)基组水平上对LLM-119的结构进行了全参数优化,获得其稳定的几何构型和键级;在振动分析的基础上求得体系的振动频率、IR谱及不同温度下的热力学性质,并得到了温度对热力学性能影响的关系式;用Monte-Carlo方法从理论上计算LLM-119的密度为1.85 g/cm3,与实验值接近,运用Kamlet公式预测爆速为8733.94 m/s.

Using 3,5-dimethyl-4-aminopyrazole as primary substance,1,4-diamino-3,6-dinitropyrazolo[4,3-c]pyrazole（LLM-119） was synthesized by six steps of diazotisation,intramolecular cyclic condensation,nitration,oxidation,decarboxylation nitration and N-amination.The structures of intermediates and target compound were confirmed by means of IR,1H NMR,13C NMR and elemental analysis.The post-treatment method of 4-diazonium-3,5-dimethylpyrazole salt was improved,the yield was increased from 77.0% to 86.1% because of using the freezing crystallization method instead of extractive method,which could avoid the use of organic reagent and shorten operation process.The mechanism of N-amination reaction was discussed in order to analyze the reason of low-yield theoretically.Using differential scanning calorimetry（DSC） and thermogravimetric（TG） as thermal analysis methods,the thermal performance of LLM-119 was studied with thermal decomposition peak temperature of 232.05 ℃ and the results showed that LLM-119 had preferable thermal stability.The structure of LLM-119 was also estimated by a B3LYP method on 6-31G（d,p） basis set in order that its steady geometric configuration and bond order were obtained.The vibrational frequencies,IR spectra and thermodynamics properties in different temperatures of the system were obtained on the basis of vibrational analysis,the relations of the effects of temperatures on thermodynamics properties were also obtained.The density of LLM-119 calculated through the Monte-Carlo method was 1.85 g/cm3,which approached with the experiment value,and the predicted detonation velocity was 8733.94 m/s by the formula of Kamlet.