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

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posted on 2011-02-21, 00:00 authored by Tobias Fendt, Niko Fischer, Thomas M. Klapötke, Jörg Stierstorfer
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 26, 8, and 9 could be determined using single crystal X-ray diffraction. The heats of formation of 29 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.