N-Rich Salts of 2-Methyl-5-nitraminotetrazole: Secondary Explosives with Low Sensitivities

2-Methyl-5-nitraminotetrazole (1) was formed by nitration of 2-methyl-5-aminotetrazole. 2-Methyl-5-aminotetrazole was obtained by an improved synthesis starting from sodium 5-aminotetrazolate, which is methylated with dimethyl sulfate in dimethyl formamide giving 2-methyl-5-aminotetrazole in 29% yield. Nitrogen-rich salts such as guanidinium (2), 1-aminoguanidinium (3), 1,3-diamino-guanidinium (4), 1,3,5-triamino-guanidinium (5), azidoformamidinium (6), hydrazinium (7), diaminouronium 2-methyl-5-nitraminotetrazolate (8), as well as an urea adduct (9), were prepared by facile deprotonation or metathesis reactions. Diaminourea was synthesized by hydrazinolysis of dimethyl carbonate with hydrazine hydrate. All compounds were fully characterized by vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry (DSC) measurements. The crystal structures of 2−6, 8, and 9 could be determined using single crystal X-ray diffraction. The heats of formation of 2−9 were calculated using the atomization method based on CBS-4M enthalpies. With these values and the experimental (X-ray) densities several detonation parameters such as the detonation pressure, velocity, energy, and temperature were computed using the EXPLO5 code. In addition, the sensitivities toward impact, friction, and electrical discharge were tested using the BAM drop hammer, BAM friction tester, as well as a small scale electrical discharge device.

2-甲基-5-硝基氨基四唑（1）通过2-甲基-5-氨基四唑的硝化反应制备而成。2-甲基-5-氨基四唑通过从5-氨基四唑钠出发的改进合成方法获得，该方法使用二甲基亚砜中的二甲基硫酸进行甲基化，得到2-甲基-5-氨基四唑，产率为29%。通过简便的脱质子化或置换反应，制备了富含氮的盐类，如胍基（2）、1-氨基胍基（3）、1,3-二氨基胍基（4）、1,3,5-三氨基胍基（5）、叠氮基甲酰胺基（6）、肼基（7）、二氨基脲2-甲基-5-硝基氨基四唑（8），以及尿素加成物（9）。所有化合物均通过振动光谱（红外和拉曼）、多核核磁共振光谱、元素分析和差示扫描量热法（DSC）进行了全面表征。2-6、8和9的晶体结构可通过单晶X射线衍射确定。使用基于CBS-4M焓的原子化方法计算了2-9的形成焓。利用这些值和实验（X射线）密度，使用EXPLO5代码计算了爆炸参数，如爆炸压力、速度、能量和温度。此外，使用BAM落锤、BAM摩擦试验机和小型电放电装置测试了这些化合物对冲击、摩擦和电放电的敏感性。