Synthesis and characterization of hypergolic salts based on bis(1H-1,2,3-triazole-1-yl) dihydroborate anion

As a new generation of potential rocket fuel, hypergolic ionic liquids, especially boron-containing hypergolic ionic liquids, have emerged as attractive alternatives for unsymmetrical dimethylhydrazine (UDMH). Herein, a series of bis(1H-1,2,3-triazole-1-yl) dihydroborate (BTDB) hypergolic ionic liquids were successfully synthesized, which had a melting point below -60 °C, high density ranging from 1.134 g/cm³ to 1.173 g/cm³, and superior density-specific impulse from 374.2 to 386.5 s g/cm³. In particular, 1,3-diallyl-1H-imidazol-3-ium bis(1H-1,2,3-triazole-1-yl) dihydroborate owned an ignition-delay time of 36 ms and the enthalpy of formation about 1.78 kJ/g, exhibiting that it was a good potential for the rocket fuels.