3-Methylazasydnone: First Energetic Mesoionic Liquid

Abstract

Energetic ionic liquids (EILs) have drawn considerable attention as potential liquid propellant components. However, most known EILs are oxygen-deficient and can be used only with external oxidizer. Herein, we report the first example of energetic mesoionic liquid, 3-methylazasydnone, that can function both as a monopropellant and in bipropellant systems. Methylazasydnone has the highest density among the methylated five-membered aromatic heterocycles in the liquid and solid state (1.49 and 1.60 g cm −3 , respectively), shows moderate volatility, good thermal stability, and is insensitive to impact. The computed performance of liquid propellant's combustion is superior to that of the benchmark energetic ionic liquid, 2hydroxyethylhydrazinium nitrate (428 vs 424 g•s cm −3 ). Overall, methylazasydnone is a promising advanced functional material for application in green liquid mono-and bipropellants.