First Example of 1,2,5‐Oxadiazole‐Based Hypergolic Ionic Liquids: A New Class of Potential Energetic Fuels

The development of liquid energetic fuels with improved properties is an important topic in space propulsion technologies. In this manuscript, a series of energetic ionic liquids incorporating a 1,2,5‐oxadiazole ring and nitrate, dicyanamide or dinitramide anion was synthesized and their physicochemical properties were evaluated. The synthesized compounds were fully characterized and were found to have good thermal stabilities (up to 219 °C) and experimental densities (1.21–1.47 g cm−3). Advantageously, 1,2,5‐oxadiazole‐based ionic liquids have high combined nitrogen‐oxygen contents (up to 64.4 %), while their detonation velocities are on the level of known explosive TNT, and combustion performance exceeds those of benchmark 2‐hydroxyethylhydrazinium nitrate. Considering the established hypergolicity with H2O2 in the presence of a catalyst, and insensitivity to impact, synthesized ionic liquids have strong application potential as energetic fuels for space technologies. Liquid energy: a novel type of promising thermally stable energetic fuels incorporating 1,2,5‐oxadiazole ring and explosophoric anions is reported for the first time. Prepared materials have high nitrogen‐oxygen content and high heats of explosion retaining low sensitivity to impact which enables their strong potential for various applications.