Nitration Products of 5‐Amino‐1H‐tetrazole and Methyl‐5‐amino‐1H‐tetrazoles – Structures and Properties of Promising Energetic Materials

Abstract

The nitration of 5-amino-1H-tetrazole (1), 5-amino-1-methyl-1H-tetrazole (3), and 5-amino-2-methyl-2H-tetrazole (4) with HNO 3 (100%) was undertaken, and the corresponding products 5-(nitrimino)-1H-tetrazole (2), 1-methyl-5-(nitrimino)-1H-tetrazole (5), and 2-methyl-5-(nitramino)-2H-tetrazole (6) were characterized comprehensively using vibrational (IR and Raman) spectroscopy, multinuclear ( 1 H, 13C, 14 N, and 15 N) NMR spectroscopy, mass spectrometry, and elemental analysis. The molecular structures in the crystalline state were determined by single-crystal X-ray diffraction. The thermodynamic properties and thermal behavior were investigated by using differential scanning calorimetry (DSC), and the heats of formation were determined by bomb calorimetric measurements. Compounds 2, 5, and 6 were all found to be endothermic compounds. The thermal decompositions were investigated by gas-phase IR spectroscopy as well as DSC experiments. The heats of explosion, the detonation pressures, and velocities were calculated with the software EXPLO5, whereby the calculated values are similar to those of common explosives such as TNT and RDX. In addition, the sensitivities were tested by BAM methods (drophammer and friction) and correlated to the calculated electrostatic potentials. The explosion performance of 5 was investigated by Koenen steel sleeve test, whereby a higher explosion power compared to RDX was reached. Finally, the long-term stabilities at higher temperatures were tested by thermal safety calorimetry (FlexyTSC). X-Ray crystallography of monoclinic 2 and 6, and orthorhombic 5 was performed.

Highly Enantioselective Synthesis of γ‐Nitroketones Containing a Terminal Alkene Moiety by means of Organocatalyzed Conjugate Addition between Nitroalkene and Enones

“…In contrast, the solubility of the double deprotonated salt 4 is comparatively low in water, which means, that single crystals for the structure determination have to be grown directly from the aqueous reaction mixture after the addition of hydroxylamine to the free acid. The starting materials 5‐nitriminotetrazole as well as the methylated compounds 1‐methyl‐5‐nitriminotetrazole and 2‐methyl‐5‐nitraminotetrazole were synthesized according to literature 11…”

Synthesis and Characterization of 5-Amino-1-nitriminotetrazole and Its Salts

“…The bonds length of compound 2 are similar to that of 5-nitroiminotetrazoles [12]. There have a little elongation for nitro group bonds O1-N6 and O2-N6, shorten for N5-N6 after forming the anion in compounds 3 and 4.…”

“…The simple nitrosubstitued tetrazoles, such as 5-nitrotetrazole [12], 5-nitroiminotetrazole [13], show high detonation velocities but sensitive toward impact and friction, while their sensitivities can be improved by the formation of salts by reacting with the corresponding organic bases. 5-Amino-1-nitriminotetrazole (2) has the relative high nitrogen content of 67.6 % among the reported nitrotetrazole precursors.…”

A DFT study on the structure–property relationship of amino-, nitro- and nitrosotetrazoles, and their N-oxides: new high energy density molecules

“…The amino group (NH 2 ) stabilizes the compounds, however, the nitro (NO 2 ) and nitroso (NO) groups destabilize the ring system and increase the sensitivity of the materials. Several nitrotetrazoles and their salts were synthesized for pyrotechnic compositions, gas generator, propellants, high explosives, and primers in prime charges [2][3][4][5][6][7][8][9][10][11][12][13][14]. Depending on the ring substituents of tetrazole, explosive properties can be tailored to span the spectrum of sensitivity from insensitive to highly sensitive.…”