多硝基尿酸衍生物含能性质的理论研究

为了寻找兼具优异爆轰性能和良好热力学及动力学稳定性的高能材料, 本文设计了15个硝基尿酸化合物, 运用密度泛函理论, 对其性质进行了研究. 通过半经验的K-J方程和比冲量预测了其爆炸性能, 结果表明, 所设计分子的爆热、 分子密度、 爆炸速率和爆炸压强同硝基取代基数目之间存在较强的线性关系. 三硝基尿酸和四硝基尿酸衍生物的爆炸速率超过了8.0 km/s, 爆炸压强超过了30 GPa, 并且大多数衍生物的比冲量要高于目前经常使用的炸药黑索金. 通过计算N—NO₂键的解离能、 特征落高、 分子的自由空间预判了衍生物的稳定性和撞击感度, 结果显示, 绝大多数分子有大于80 kJ/mol的键解离能. 本文的理论结果可以为实验上设计合成新的高能材料提供一些有用的信息.

Computational Studies on Energetic Performance of Polynitro-substituted Uric Acid Derivatives

To search for potential energetic materials with large energy density and acceptable thermodynamics and kinetics stability, fifteen nitro uric acid derivatives were investigated by density functional theory. The detonation properties of all the molecules were evaluated according to Kamlet-Jacobs equations and specific impulses. Calculated results show that there are good linear relationships between detonation heat, densities, detonation velocities, detonation pressures and the numbers of nitro groups, respectively. It is found that tri-nitro and tetra-nitro uric acid derivatives show detonation velocity of about 8.0 km/s, and a detonation pressure of 30 GPa, and most of the investigated molecules have higher specific impulse than hexahydro-1,3,5-trinitro-s-triazine(RDX). By analyzing bond dissociation energies(BDEs) of N—NO₂ bonds, impact sensitivity, and the free space per molecule in the unit cell, most of the investigated molecules exhibit satisfactory stability(BDEs > 80 kJ/mol). The results of this study may provide basic information for the further study of this kind of compounds and the molecular design of novel energetic materials.