Catalytic Ignition of Ionic Liquid Fuels by Ionic Liquids
AIR FORCE RESEARCH LAB EDWARDS AFB CA ROCKET PROPULSION DIV
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The majority of current hypergolic ionic liquids ILs are hypergolic spontaneous ignition upon contact between a fuel and oxidizer with nitric acid in one of its several formulations. Only very few have been found to be hypergolic with higher performing N2O4. While ILs can be considered green or less hazardous in certain aspects when compared to hydrazine, both nitric acid and N2O4 are highly hazardous. To gain a true advantage, a more environmentally friendly oxidizer must be considered. Hydrogen peroxide might be an attractive alternative for some systems, especially because of its benign decomposition products. Although the permissible exposure limit for hydrogen peroxide is only 1 ppm in air, the high boiling points of its water solutions, 141 degrees C 90 hydrogen peroxide and 148 degrees C 98 hydrogen peroxide, result in relatively low vapor pressures at 25 degrees C of only 0.5 KPa and 0.3 KPa, respectively. In 2011, we showed that ILs can be hypergolic with H2O2 but it required complex aluminumborohydride anions to realize acceptable ignition delay ID times. Here we describe how certain ILs can be employed as ignition enhancing catalyst to make many ILs hypergolic.
- Physical Chemistry
- Combustion and Ignition
- Liquid Rocket Propellants