基于双键异构的偕二硝基烯类低感高能炸药的合成及性能研究

Gem-dinitro-olefin compounds, represented by the FOX-7, are an important family of low sensitivity high explosives with excellent performance. However, the lack of their synthetic methods restricts the development of these high explosives. This project aims to develop novel high explosives by virtue of a gem-dinitro-olefin isomerization strategy. In this strategy, the construction of gem-dinitro structure will be first achieved by the isomerization of double bonds, and then both spontaneous and manageable isomerization will be employed to synthesize the desired gem-dinitro-olefin structure. In the presence of gem-dinitro-olefin and amino groups as high-energy unit and low sensitivity unit respectively, the design of low-sensitivity high explosives will be achieved by controlling the multiple factors including reasonable arrangement of high-energy/low sensitivity groups, molecular planarity, strong hydrogen bonding and effective crystal stacking. The spontaneous isomerization of gem-dinitro-olefin group will be completed by the screening of skeleton structure, while the controlled isomerization is achieved by both regulating the reaction conditions and using the N-amination strategy. The influence factors of isomerization process and isomerization mechanism will be also explored. In addition, the molecular structures, crystal structures, thermal stability, detonation performance and sensitivities of gem-dinitro-olefin compounds will be also studied, which will help us to obtain the relationships between structure and properties and to reveal the effect of molecular structure on their energy and sensitivity as well. This study will offer many insights into the gem-dinitro-olefin compounds, thereby providing a theoretical basis and experimental support for the development of better detonation-performing explosives with low sensitivity.

以FOX-7为代表的偕二硝基烯类化合物是一类性能优异的潜在低感高能单质炸药，而构建方法单一是制约该类炸药发展的主要因素之一。本项目拟采用双键异构的策略，首先构筑易合成的偕二硝基结构，然后通过自发异构和可控异构实现新型偕二硝基烯类炸药分子的构建。以偕二硝基烯为高能单元，氨基为降感单元，综合考虑高能/降感基团的合理排布、分子平面性、强氢键作用、空间有效堆积等多因素的影响实现低感高能分子的设计。通过骨架结构的筛选与优化实现偕二硝基烯的自发异构制备，通过外界条件的调控与N-氨基化的结合实现偕二硝基烯的可控异构制备，探索自发异构和可控异构的控制因素，揭示异构机制。研究偕二硝基烯炸药分子的物化、安全和爆轰性能，获得结构与性能的内在关系与规律，揭示偕二硝基烯结构对能量与感度适配性的影响规律。本研究将深化对偕二硝基烯结构单元本征特性的理解，为新型低感高能炸药的创制提供理论依据和实验数据支撑。

围绕项目研究目标与研究内容，以偕二硝基烯为高能单元，氨基为降感单元，感度和能量适中的噁二唑环为骨架，设计了多种，具有平面性和强分子间和分子内氢键作用的低感高能分子。分别采用氯肟结构硝化、乙酸乙酯基团硝化和FOX-7结构单元转化等三种构建方式，制备了5类20余种新型偕二硝基类低感高能炸药分子，通过反应条件优化，掌握了偕二硝基基团的制备，实现了可控异构制备。同时通过将含能离子盐的阴阳离子组合于同一分子的策略，制备出一种兼具离子盐低感度和中性分子高密的优势的内翁型新含能分子。对这些化合物的分子结构，晶体结构等进行了鉴定，获得了这些分子的晶体结构和堆积参数；测试了热分解温度，感度等安全和爆轰性能，获得了该系列化合物的能量特性参数。通过对比和计算结构和堆积参数与能量特性参数的相关性，获得结构与性能的内在关系与规律，揭示了偕二硝基烯结构对能量与感度适配性的影响规律。本项目的研究大大加深了对偕二硝基基团的制备和能量特性的理解，偕二硝基具有高能量、高密度的特点，通过合理的结构设计将偕二硝基转化为偕二硝基烯结构可明显降低该基团的感度，一定程度上实现能量与感度的协调。系列化合物的开发与构效关系研究，特别是内翁型含能分子的开发为为新型低感高能炸药的创制提供了新的思路与相关理论依据和实验数据支撑。