苯的硝基和叠氮基衍生物的理论研究

Theoretical Studies on the Nitro and Azido Derivatives of Benzene

在密度泛函理论B3LYP/6-31G*水平下优化了91个苯的硝基(NO2)和叠氮基(N3)衍生物的分子几何构型,预测了它们的密度和生成热,采用Kamlet-Jacobs方法计算了爆速和爆压,筛选得到11种爆轰性能较好的高能量密度化合物(HEDC),计算了它们的多个可能的热解引发键的键离解能(BDE)以及按"氧化呋咱机理"分解时的活化能(Ea).结果表明,当分子中有NO2与N3相邻时,分解按"氧化呋咱机理"进行,分解反应的Ea均大于100 kJ/mol;分子中没有NO2和N3相邻时,热解始于C-NO2或C-N3均裂,裂解的BDE都大于200 kJ/mol.只含NO2或N3的7个物质的稳定性好于同时含NO2和N3的物质,而只含N3的物质的稳定性又好于只含NO2的物质,五叠氮苯和六叠氮苯具有很出色的爆轰性能和稳定性.无论是能量还是稳定性方面,筛选得到的11种物质基本符合HEDC的要求.

The geometries of the nitro and azido substituted derivatives of benzene were optimized at the B3LYP/6-31 G＊ level of density functional theory, the detonation velocity and pressure were calculated with the Kamlet-Jacobs method and eleven candidates satisfying the energetic requirements for high energy density compound （HEDC） were found. The bond dissociation energies （BDE） of the possible trigger bonds were computed for these candidates and the activation energy （Ea） of the pyrolysis process following ＂fu- roxan mechanism＂ were also evaluated for the candidates with the adjacent nitro and azido groups. The cal- culated results show that Ea is much lower than BDE, implying that when there are adjacent azido and nitro groups in molecule, the stability of compounds will be greatly decreased and the pyrolysis happens in ＂furoxan mechanism＂. Otherwise, the pyrolysis will be initiated from the rupture of C-NO2 or C-N3 bond. The calculated BDE are essentially larger than 200 kJ/mol and all Ea are larger than 100 kJ/mol, therefore, the eleven candidates basically satisfy the energetic and stability requirements as HEDC.