Energetic N‐nitrooxyethylimidazolium Salts: Synthesis, Structures and Properties

Abstract

AbstractEnergetic salts 2 and 4 a‐f, comprising an energetic 1,2‐dimethyl‐3‐(2‐nitrooxyethyl)imidazolium cation and energetic anions such as nitrate, 3,5‐dinitro‐1,2,4‐triazolate, picrate, 3‐nitro‐5‐oxo‐1,2,4‐triazolate, dinitromethanide, dinitramide and 5‐nitrotetrazolate, were easily synthesized via quaternization, nitration and metathesis. The salts were fully characterized by Fourier transform infrared (FT‐IR) spectroscopy, ultraviolet‐visible (UV‐Vis) spectroscopy, electrospray ionization mass spectrometry (ESI‐MS), nuclear magnetic resonance (NMR) or elemental analysis. The structure of picrate 4 b was also studied via single crystal X‐ray diffraction. The thermal properties of 2 and 4 a‐f were investigated by differential scanning calorimetry (DSC) and thermo‐gravimetric analysis (TGA). DSC data show that 3, 5‐dinitro‐1, 2, 4‐triazolate 4 a, dinitromethanide 4 d, dinitramide 4 e and 5‐nitrotetrazolate 4 f are typical ionic liquids with a glass transition temperature of −58 °C to −22 °C and a melting point below 100 °C. TGA indicates that 2, 4 a‐c and 4 f have a good thermal stability and a decomposition temperature above 155 °C. Besides, the energetic properties of salts 2 and 4 a‐f were calculated. The detonation velocities of the salts are 6.62–7.42 km/s, approaching those of TNT.