摘要
新型高能不敏感含能材料的合成对于武器装备能量水平和安全性的提升有重要意义。以5,6‑二氨基呋咱并[3,4‑b]吡嗪为原料,经氧化反应首次合成了5,6‑二氨基呋咱并[3,4‑b]吡嗪‑4,7‑二氧化物(DAFPO),用核磁共振(氢谱、碳谱、氮谱)、红外光谱和元素分析对其进行了表征。以乙酸乙酯为溶剂使用缓慢蒸发法获得了DAFPO•2H2O的单晶,利用X‑射线单晶衍射和Hirshfeld表面分析完成了结构解析和分子间相互作用研究。结果表明,DAFPO•2H2O属正交晶系,Pna21空间群,296 K下晶体密度1.806 g·c
图文摘要
A novel insensitive energetic material, 5,6‑diaminofurazano[3,4‑b]pyrazine‑4,7‑dioxide (DAFPO) was synthesized and fully characterized. The impact and friction sensitivities were measured by BAM method. The detonation velocity and pressure were calculated by EXPLO5 code.
随着现代军事科学技术的发展,高价值武器装备或作战平台对于武器弹药安全性和抗打击能力的要求不断提高。因此,开发兼具高能量水平与不敏感特性的新型化合物成为含能材料领域的重要发展方
氮杂芳环化合物的N‑氧化物是设计高能低感化合物的优良的结构单
呋咱并吡嗪骨架是一种具有较高能量密度的氮杂稠环结构,国内外各课题组以此为结构单元设计出多种性能优良的含能化合
试剂:5,6‑二氨基呋咱并[3,4‑b]吡嗪(DAFP)由实验室自
仪器:ZF‑Ⅱ型三用紫外仪,上海市安亭电子仪器厂;NEXUS 870型傅里叶变换红外光谱仪,美国热电尼高力公司;AV 500型(500 MHz)超导核磁共振仪,瑞士BRUKER公司;VARIO‑EL‑3型元素分析仪,德国EXEMENTAR公司;SMART APEX II CCD面探X射线单晶衍射仪,瑞士BRUKER公司;Q‑200型差示扫描量热仪,美国TA公司;TA 2950热重仪,美国Nicolet公司;AccuPycⅡ1340型全自动真密度仪,美国Micromeritics公司;BFH‑10型撞击感度仪,FSKM‑10型摩擦感度仪,捷克OZM公司。
将5,6二氨基呋咱并[3,4‑b]吡嗪(1.52 g,10 mmol)加入至三氟乙酸(7.0 mL)中,搅拌至溶解。于0 ℃下向其中缓慢加入过氧化氢的50%水溶液(3.0 mL),完毕后升至室温并搅拌反应24 h,析出大量固体。过滤,粗品在真空干燥箱中60 ℃下干燥3 h,得淡黄色固体粉末1.15 g,收率62.5%。
DAFPO的合成路线见

Scheme 1
吡嗪环在过氧化氢/三氟乙酸条件下易于发生氧化反应。在该反应中,三氟乙酸和过氧化氢分别起到酸和碱的作用,使得吡嗪环N原子上的孤对电子与过氧化氢的一个O原子形成了配位键,从而将吡嗪环上的N原子氧化。从理论上分析,提高过氧化氢的用量有助于原料的彻底氧化。但是,由于产物DAFPO在水中的溶解性较好,故过氧化氢水溶液比例过高反而会导致收率下降。因此需选择合理的三氟乙酸与过氧化氢体积比。将DAFP于室温条件下反应24 h,研究了总溶剂量为10 mL时,不同比例三氟乙酸与过氧化氢水溶液对于反应收率的影响,结果如
选取尺寸0.34 mm×0.25 mm×0.13 mm的单晶,采用X‑射线单晶衍射仪进行结构解析。晶体结构解析和结构修正分别由程序SHELXS‑97和SHELXL‑97程序完

图1 DAFPO·2H2O的晶体结构
Fig.1 Crystal Structure of DAFPO·2H2O

图2 DAFPO·2H2O的晶胞堆积图(虚线表示分子间氢键作用)
Fig.2 Molecular packing diagram of DAFPO·2H2O(Dashed lines indicate intermolecular hydrogen‑bond interactions)
晶体结构分析表明,DAFPO·2H2O属于正交晶系,Pna21空间群,每个晶胞内含有4个DAFPO分子和8个H2O分子,晶体密度1.806 g·c
进一步对晶体中存在的氢键进行了分析,DAFPO·2H2O的分子间氢键数据列于

图3 DAFPO·2H2O的分子间氢键作用
Fig.3 The intermolecular hydrogen bond interactions of DAFPO·2H2O
Hirshfeld面是以晶体的电荷分布为依据,球形原子电荷密度总和为0.5的等值面,可以识别特定区域晶体的分子间相互作

a. Hirshfeld surface

b. 2D fingerprint
图4 DAFPO·2H2O的Hirshfeld面图和二维指纹图
Fig.4 Hirshfeld surface and 2D fingerprint of DAFPO·2H2O
采用DSC和TG方法研究了无水DAFPO的热稳定性(测试条件:动态氮气气氛,温度范围25~350 ℃,升温速率10 ℃·mi

图5 DAFPO的DSC曲线
Fig.5 DSC curve of DAFPO

图6 DAFPO的TG‑DTG曲线
Fig.6 TG‑DTG curves of DAFPO
基于原子化反应,使用Gaussian 0
可以看出,DAFPO的固相生成热为753.5 kJ·mo
(1)以5,6二氨基呋咱并[3,4‑b]吡嗪为原料,经氧化反应首次合成了新型含能材料5,6‑二氨基呋咱并[3,4‑b]吡嗪‑4,7‑二氧化物(DAFPO),获得DAFPO·2H2O的单晶并利用X‑射线单晶衍射仪完成结构测定。DAFPO·2H2O属正交晶系,Pna21空间群,296 K下晶体密度1.806 g·c
(2)无水DAFPO的热分解温度为131.8℃,实测密度1.86 g·c
(责编: 王艳秀)
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