Towards N-Alkylimidazole Borane-based Hypergolic Fuels

Graphical Greener rocket fuels : A series of N -alkylimidazole borane compounds has been synthesized, which display hypergolic reactivity with the oxidizer of white fuming nitric acid. Compared with popular hypergolic ionic liquids, these fuels have the advantages of low viscosity and cost-effectiveness, and easily scaled-up production. Over the past few decades, toxic and highly volatile hydrazine derivatives have been the main fuel choices for liquid bipropellants, especially in traditional hypergolic rocket engines. The search for new hypergolic fuels as replacements for hydrazine derivatives is of great interest to researchers. In this study, a series of N -alkylimidazole borane compounds has been synthesized and characterized. Interestingly, these compounds display promising applications as potential hypergolic fuels owing to their excellent physiochemical properties including low melting points, high thermal stability, low viscosities, and unique hypergolic reactivity. Compared with popular hypergolic ionic liquids, the cost-effective and scaling-up advantages of these materials highlight their promising potential as high-performance fuels in liquid bipropellant formulations.