十二氢十二硼酸双(二烷基-5-氨基四唑)盐的合成, 表征及热性能

We tried combining dodecahydrodecaborane anion (B₁₂H₁₂ ^2-) with aminotetrazole cation into a series of new borohydrino-tetrazolium salt as a kind of energetic materials. Firstly, by using 1-or 2-5-aminotetrazole (5-ATZ) as the raw material, dialkylated 5-aminotetrazolium iodide was synthesized via dialkylation reaction with methyl iodide and ethyl iodide. And then, the dialkylated 5-aminotetrazolium iodides was used to react with potassium dodecylhydrodecaborate in an aqueous solution by metathesis. Finally, eleven novel bis(dialkyl-5-aminotetrazolium) dodecahydrododecaborates were synthesized. All of them were in yield of above 70%, and their chemical properties were stable under the conditions of purification and drying. These compounds have been characterized by FT-IR, ¹H NMR, ¹³C NMR, ¹¹B NMR, mass spectrometry, and elemental analysis. In inspecting their thermal properties using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) technologies, the results showed that eleven kinds of bis(dialkyl-5-aminotetrazolium) dodecahydrododecaborates have higher thermal stability and the thermal decomposition temperatures of them are mostly above 200℃. In molecular structures, their thermal stability decrease with the increase of the 4-position alkyl when the 1-position alkyl maintains the same. The rapid thermal decomposition of the five compounds, 1,4-dimethyl, 1-methyl-4-ethyl, 1,3-dimethyl, 1-methyl-3-ethyl, and 1-ethyl-3-methyl, occurred before the melting, and the rapid thermal decomposition of the other 6 compounds occurred after the crystals melting. These high-energetic compounds are of great importance in developing new high-performance propellants.