Hypergolic N,N-dimethylhydrazinium ionic liquids.

N,N-Dimethylhydrazinium dicyanamide and nitrocyanamide ionic liquids (ILs) were prepared by quaterization of N,N-dimethylhydrazine with alkyl halides followed by metathesis reactions with silver dicyanamide or silver nitrocyanamide. The key physicochemical properties, such as melting point and decomposition temperatures, density, viscosity, heat of formation, detonation pressure and velocity, and specific impulse were measured/calculated. The impact of anions and alkyl-substituted cations on these properties is demonstrated. Droplet tests with white-fuming nitric acid (WFNA) as an oxidizer were utilized to show that the 14 new N,N-dimethylhydrazinium salts are hypergolic with ignition delay (ID) times ranging from 22 to 1642 ms, thereby suggesting that some may have potential as bipropellants.