Synthesis and properties of novel 1,2,5-oxadiazole-based nitramide salts with fluorodinitromethyl as an energetic moiety

To develop oxidizers with superior energy density, this study presents the design and synthesis of three energetic salts based on <i>N</i>-(4-fluorodinitromethyl-1,2,5-oxadiazol-3-yl)nitramide. The structures of these compounds were comprehensively characterized by Fourier-transform infrared spectroscopy (FT-IR), high-resolution mass spectrometry (HRMS), single-crystal X-ray diffraction (SC-XRD), and multinuclear NMR spectroscopy (¹³C, ¹⁹F). Their thermal behaviors were evaluated using simultaneous thermogravimetric-differential scanning calorimetry (TG-DSC). The results indicate that the thermal decomposition temperatures for the potassium salt, ammonium salt, and hydroxyammonium salt are 143.2°C, 165.4°C, and 140.5°C, respectively. The ammonium salt exhibits a density of 1.75 g/cm³, an enthalpy of formation of 37.6 kJ/mol, a detonation velocity of 8712 m/s, and a detonation pressure of 32.1 GPa. In comparison, the hydroxyammonium salt has a higher density (1.89 g/cm³) and enthalpy of formation (65.0 kJ/mol), along with superior detonation performance (detonation velocity: 9252 m/s, detonation pressure: 38.1 GPa). Notably, the energetic characteristics of the hydroxyammonium salt are comparable to those of HMX, underscoring its high energetic potential as novel oxidizer.