Abstract:The reactions of 8 newly synthesized ionic liquids containing BH3(CN)BH2(CN)- anion, (I.L.1~ I.L.8), with white fuming nitric acid (WFNA) and red fuming nitric acid (RFNA) respectively were tested by using the long focus microscope-high speed photography technique and droplet method test device, respectively. Results show that each test achieves stable hypergolic reaction and two different flame development processes were observed. Specifically, after the contact of I.L.8 with WFNA, the microexplosion is occurred and hypergolic ignition is occurred in a short time, while after the contact of I.L.8 with RFNA the aplashing of secondary droplet is occurred. Due to the effect of Leiden Frost effect, the foam like droplets after reaction is rebounded and a short combustion reaction is appeared, the hypergolic ignition is occurred after a long time. For the ionic liquid with same heterocyclic core, the ignition delay time of the ionic liquid containing the allyl group on the side chain is the shortest, followed by the ionic liquid containing ethyl, while the ignition delay time of the ionic liquid containing butyl and WFNA is the longest. For the ionic liquid with the same side chain, the ignition delay time of the ionic liquid containing the pyridine heterocyclic ring is the longest, followed by the imidazole heterocyclic ionic liquid, and the ignition delay time of the ionic liquid containing tetrahydropyrrole reacted with WFNA is the longest.The higher the enthalpy of formation is, the shorter the ignition delay time is.