Two Energetic Salts based on 5,5′-Bitetrazole-1,1′-diolate: Syntheses, Characterization, and Properties

Abstract

Two salts based on 1H,1′H‐5,5′‐bitetrazole‐1,1′‐diolate (BTO) anion with pyrazole (1) and imidazole (2) cations were synthesized with metathesis reactions. Structural characterization was accomplished for them by using the element analysis, Fourier transform infrared spectroscopy (FT‐IR), NMR and mass spectrum, and X‐ray single crystal diffraction. Thermal analysis for the title salts were determined by means of differential scanning calorimetry (DSC) and thermogravimetry‐derivative thermogravimetry (TG‐DTG) as well as the calculation of non‐isothermal kinetic parameters. Consequently, both salts shown acceptable thermal stabilities as the decomposition temperatures were over 200 °C. The enthalpies of formation were calculated for these salts using the measured combustion energies with a result of 70.6 kJ·mol–1 for 1 and –47.8 kJ·mol–1 for 2, respectively. Impact and friction sensitivities were also tested and the results indicated that these salts both have low sensitivities (>40 J, 120 N). The title energetic salts possess acceptable performance, they can therefore be applied in the field of energetic materials.

Novel insensitive energetic-cocrystal-based BTO with good comprehensive properties

“…More importantly, the cocrystal is also much superior to the non-cocrystal IMBTO (1.588 g cm −3 ) as recently published. 20 The graphite-like structure of CIMBTO in the solid state was the same as that of the predicted mode and highly contributed to the high density in Fig. 3 .…”

“…The metathesis reaction is analogous to that of non-cocrystal IMBTO. 20 Thereafter, a cocrystallization experiment was conducted by dissolving the same equivalent of H 2 BTO and IMBTO in a minimum amount of distilled water, and the mixtures were stirred slowly to dissolve. Then, the solution was filtered and the solvent was evaporated over a period of several days at room temperature.…”

“…To verify our assumption further, we studied the packing coefficient, which was calculated as the ratio of the total molecular volume to the unit cell volume, where 73.64% for CIMBTO was closer to the value for H 2 BTO itself (74.35%) and higher than that of IMBTO (71.53%). 20 This result signies that the volume and amount of the internal cavities were largely reduced in the cocrystal and that the cocrystal was a new compound.…”

“…The expected cocrystal imidazolium BTO (CIMBTO) displayed a desirable crystal density of 1.720 g cm −3 , which is significantly higher than that of the non-cocrystal IMBTO (1.588 g cm −3 ) recently published. 20 Meanwhile, multinuclear nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, elemental analysis (EA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) were employed to characterize the prepared cocrystal. The resultant cocrystal also exhibited potentially decent thermal stability, good detonation properties, and extremely low sensitivity toward accidental stimuli; these characteristics highlight the cocrystal's potential energetic application.…”