以3-氨基-1,2,4-三唑为原料,经过重氮化、取代、分子内缩合、硝化反应合成4-硝基-2-(1-硝基-1,2,4-三唑-3-基)-1,2,3-三唑(DNDTz),总收率为25.02%。采用红外光谱、1 H NMR、13 C NMR、质谱及元素分析对中间体及目标产物的结构进行了表征;采用DSC、TG研究了DNDTz的热行为,得到DNDTz放热分解峰为160.8℃,热分解过程分为三个阶段,质量损失分别为13.5%、52.39%、27.15%。结果表明,DNDTz没有熔融过程,而是直接分解。采用B3PW91/6-31G(d,p)方法对DNDTz进行结构优化,获得稳定构型、键级和热力学性质以及温度与内能、热容和熵的关系式;用Monte-Carlo方法结合Politzer校正公式,得到DNDTz的理论密度为1.812g/cm3,用VLW公式预测其爆速为8.604km/s。
The oxidative cyclization reaction of 2-nitroaniline via sodium hypochlorite to yield benzo- furoxan is investigated by the hybrid density functional theory B3LYP/6-31G（d,p） method. Solvent effects are estimated with the polarizable continuum model to optimize structures. The title reaction is predicted to undergo two pathways, each of which is a stepwise process. Path A includes four steps, namely oxidization, H-attack, hydrolysis, and cyclization. Path B involves the nucleophilic attack of OH^- to the H atom of the N-H bond and the proton transfer to the N atom of amino group leading to the cleavage of the N-H single bond in the amino group. The calculated results indicate that path A is favored mechanism for the title reaction. Furthermore, it is rational for one water molecule serving as a bridge to assist in the hydrolysis step of Path A and our calculations exhibit that this process is the rate-determining step.
