四硝基吡咯及其衍生物结构与性能的理论研究

为了寻找新型高能量密度材料,设计了四硝基吡咯及其甲基、氨基、硝基衍生物。在DFT-B3LYP/6~(-3)1G*水平下对模型化合物进行了几何结构全优化。在DFT-B3LYP/6~(-3)11++G**水平计算了模型化合物的生成焓、爆轰性能。自然键轨道(NBO)分析了模型化合物引发键的强度进而考察了其热安全性。计算结果表明:1-甲基四硝基吡咯密度为1.88 g·cm~(~(-3)),爆速和爆压分别为8.66 km·s~(-1)和34.10 GPa,其爆轰性能具有与1,3,5-三硝基~(-1),3,5-三氮杂环己烷(RDX)相当的爆轰性能;四硝基吡咯、1-氨基四硝基吡咯密度分别为1.93 g·cm~(-3)和2.04 g·cm~(-3),爆速均为9.01 km·s~(-1),爆压分别为37.54 GPa和38.73 GPa,具有与1,3,5,7-四硝基~(-1),3,5,7-四氮杂环辛烷(HMX)相当的爆轰性能;由于五硝基吡咯中含有五个硝基,其热安全性最差,N(5)—NO2键离解能仅为60.8 k J·mol~(-1)。计算值与之前的实验值具有较好的一致性,表明计算值可靠。

Theoretical Study on Structure and Properties of Tetranitropyrrole and Its Derivatives

In order to search new high-energy density materials,2,3,4,5-tetranitropyrrole(TNP) and its methyl-,amino-,nitro-substituted derivatives were designed.Their structures were optimized at the DFT-B3 LYP/6-31 G* level.Heats of formation,detonation properties were calculated at the DFT-B3LYP/6-311++G** level.Nature Bond Orbital(NBO) analysis was carried to understanding the strength of trigger bond and further to access the thermal stability of the model compounds.The calculated results are as follows:the density,detonation velocity and detonation pressure of 1-methyl-2,3,4,5-tetranitropyrrloe are 1.88 g·cm-3,8.66 km·s-1 and 34.10 GPa,respectively,which is comparable to the detonation properties of 1,3,5-trinitro-1,3,5-triaza-cyclohexane (RDX).The densities of 2,3,4,5-tetranitropyrrole and 1-amino-2,3,4,5-tetranitropyrrole are 1.93 g·cm-3 and 2.04 g·cm-3,respectively;the detonation velocities are both 9.01 km·s-1,and detonation pressures are 37.54 GPa and 38.73 GPa,which suggests that the detonation properties of TNP and ATNP are both comparable to that of 1,3,5,7-tetranitro-1,3,5,7-tetraza-cyclooctcme (HMX).With containing five nitro groups,the BDE of nitro group N(5)—NO2 is 60.8 kJ·mol-1,suggesting that pentanitropyrrole has the poorest thermal stability in all five model compounds.The calculated results and previous experimental work agree reasonably well one another,showing values in this paper are reasonable.