Salts of Methylated 5-Aminotetrazoles with Energetic Anions

Abstract

1-methyl-5-aminotetrazole (4, MAT) can easily be protonated by strong acids, yielding known but largely uninvestigated 1-methyl-5-aminotetrazolium nitrate (4a) and perchlorate (4b). Methylation, rather than protonation, of 4 with iodomethane followed by the exchange of the iodide (5a) for nitrate (5b), perchlorate (5c), azide (5d), and dinitramide (5e) yields a new family of energetic methylated aminotetrazole salts. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray structure determination. Compounds 4a, 4b, and 5c crystallize in the monoclinic space group P2(1)/n, whereas compounds 5b and 5e crystallize in the orthorhombic space group P2(1)2(1)2(1) and 5d in the orthorhombic Fddd. Initial safety testing (impact, friction, and electrostatic sensitivity) and thermal stability measurements (DSC) were also carried out. The MAT salts all exhibit good thermal stabilities (decomposition above 150 degrees C). The constant volume energies of combustion (DeltacU) of 4a, 5b, 5d, and 5e were determined to be -2510(10) cal/g, -3190(30) cal/g, -4500(100) cal/g, and -2570(70) cal/g, respectively, experimentally using oxygen bomb calorimetry. From the experimentally determined density, chemical composition and energies of formation (back calculated from the heats of combustion), the detonation pressures and velocities of 4a (8100 m/s, 25.6 GPa), 5b (7500 m/s, 20.2 GPa), 5d (8200 m/s, 21.7 GPa), and 5e (7500 m/s, 21.2 GPa) were predicted using the EXPLO5 code.

1,2,4‐Triazolium‐Cation‐Based Energetic Salts

“…This is a similar effect to that observed in other nitrogen-containing heterocycles upon alkylation or protonation of the heterocyclic ring. [26,37] The methyl group has a shift of % 34 ppm, in keeping with compounds containing an N-methylated azole ring. [31,37] 15 N NMR spectroscopy shows six signals for the six different nitrogen atoms in the cation (Figure 3).…”

“…[26,37] The methyl group has a shift of % 34 ppm, in keeping with compounds containing an N-methylated azole ring. [31,37] 15 N NMR spectroscopy shows six signals for the six different nitrogen atoms in the cation (Figure 3). When the spec- trum is recorded with broadband decoupling, the resonances of the nitrogen atoms in close proximity to protons are strong and positive.…”

New Energetic Materials featuring Tetrazoles and Nitramines – Synthesis, Characterization and Properties

“…tetrazoles) in combination with energetic substituents such as nitro groups (R-NO 2 ) [3,4], nitrate esters (R-O-NO 2 ) [5], azide groups (R-N 3 ) [6] or nitramine functionalities (R 2 N-NO 2 ) [7,8]. Also the formation of tetrazolium salts with oxygen rich counter anions such as NO 3 - [9,10] or N(NO 2 ) 2 - [11,12] are in the focus of our research, since these compounds have balanced oxygen contents. We recently reported on the synthesis and characterization of 2-(2-nitro-2-azapropyl)-5-nitrotetrazole [13], which has an appropriate oxygen balance similar to that of RDX (hexogen).…”

Ionische Flüssigkeiten als hypergole Treibstoffe

“…[37][38][39][40][41][42] Auf der Grundlage von Berechnungen [43] fanden wir heraus, dass die Bildungswärme eines der wichtigsten Charakteristika für hypergole Salze ist und in direktem Zusammenhang mit der Zahl der StickstoffStickstoff-Bindungen in der ionischen Spezies steht. Daher begannen wir mit der Suche nach neuen Ionen mit einer hç-heren Konzentration an Stickstoff-Stickstoff-Bindungen.…”