Borohydride Ionic Liquids as Hypergolic Fuels: A Quest for Improved Stability.
Deepak Chand1, Jiaheng Zhang1, Jean'ne M Shreeve2
1Department of Chemistry, University of Idaho, Moscow, ID, 83844-2343 (USA), Fax: (+1) 208-885-9146.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 31, 2015
Summary
New borohydride ionic liquids offer safer, greener alternatives to hazardous hydrazine rocket fuels. These compounds show promise for bipropellant formulations with excellent ignition properties and improved stability.
Area of Science:
- Chemistry
- Materials Science
- Aerospace Engineering
Background:
- Hydrazine fuels are hazardous due to toxicity and high vapor pressure.
- Ionic liquids (ILs) are being explored as safer alternatives to traditional rocket fuels.
- Borohydride-containing ILs offer potential for improved fuel performance and safety.
Purpose of the Study:
- To synthesize novel borohydride-containing ionic liquids.
- To evaluate their properties as potential rocket fuels.
- To investigate their stability and performance characteristics.
Main Methods:
- Efficient synthesis of eight new borohydride-containing ionic liquids.
- Characterization of ignition-delay times (ID).
- Assessment of hydrolytic stability with varying alkyl substituents.
Main Results:
- Two compounds exhibited very short ignition-delay times (3 and 8 ms).
- Long-chain alkyl substituents significantly improved hydrolytic stability.
- 1,3-Di-(n-octyl)-imidazolium borohydride demonstrated water stability.
- 1,3-Di-(n-butyl)-imidazolium borohydride was identified as a liquid crystal.
Conclusions:
- Borohydride ionic liquids are promising, environmentally friendly alternatives to hydrazine fuels.
- They offer advantages such as negligible vapor pressure, good ignition delay, and reduced costs.
- Potential applications include bipropellant formulations, reducing agents, and hydrogen storage materials.
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