Synthesis and Improved Properties of Hypergolic Boronium‐Based Ionic Liquids

A series of asymmetric monoimidazolium dihydroboronium-based ionic liquids (ILs) were synthesized from amine-boranes. All the resulting ILs were fully characterized by 1H and 13C NMR, IR spectroscopy, elemental analysis or high resolution mass spectrum. Compared with the symmetric bisimidazolium dihydroboronium-based ILs, these new ILs exhibited improved properties with shorter ignition delay times (IDs), higher densities, and lower phase transition temperature showing the promising application potential as green propellants.