Cyanotetrazolylborohydride (CTB) anion-based ionic liquids with low viscosity and high energy capacity as ultrafast-igniting hypergolic fuels

Abstract

A series of hypergolic cyanotetrazolylborohydride (CTB) anion-based ionic liquids have been synthesized by a straightforward N-hydroboration of tetrazole followed by a salt metathesis reaction, which exhibited remarkably low viscosity (<20 mPa s), high density (often >1.1 g cm⁻³), and ultra-short ignition delay time (as short as 1.4 ms) upon contact with white fuming nitric acid (WFNA).