The acidity of the amine H atoms and the consequent salt formation ability of ethylenedinitramine (EDNA) were analyzed in an attempt to improve the thermal stability of EDNA. Two short-chain alkanediamine bases, namely propane-1,3-diamine and butane-1,4-diamine, were chosen for this purpose. The resulting salts, namely propane-1,3-diaminium N,N′-dinitroethylenediazanide, C3H12N2
2+·C2H4N4O4
2−, and butane-1,4-diaminium N,N′-dinitroethylenediazanide, C4H14N2
2+·C2H4N4O4
2−, crystallize in the orthorhombic space group Pbca and the monoclinic space group P21/n, respectively. The resulting salts display extensive hydrogen-bonding networks because of the presence of ammonium and diazenide ions in the crystal lattice. This results in an enhanced thermal stability and raises the thermal decomposition temperatures to 202 and 221 °C compared to 180 °C for EDNA. The extensive hydrogen bonding present also plays a crucial role in lowering the sensitivity to impact of these energetic salts.
为了提高乙二胺四乙酸(EDNA)的热稳定性,我们分析了胺 H 原子的酸性以及由此产生的成盐能力。为此选择了两种短链烷二胺碱,即丙烷-1,3-二胺和丁烷-1,4-二胺。由此产生的盐,即丙烷-1,3-二氨基 N,N′-二硝基乙二氮杂烷,C3H12N2
2+-C2H4N4O4
2-,以及丁烷-1,4-二氨基 N,N′-二硝基乙撑二氮杂烷,C4H14N2
2+-C2H4N4O4
2- 分别在正交空间群 Pbca 和单斜空间群 P21/n 中结晶。由于铵离子和重氮离子存在于晶格中,因此生成的盐显示出广泛的氢键网络。这就增强了热稳定性,并将热分解温度提高到 202 和 221 °C,而 EDNA 的温度仅为 180 °C。存在的大量氢键在降低这些高能盐对冲击的敏感性方面也发挥了重要作用。