(174e) Environmental Life Cycle Assessment of New Energetic Materials

There is growing interest in the development of new energetic ionic liquids for use as aerospace propellants and explosives. Due to their negligible vapor pressure ionic liquids are usually considered as “green” alternatives to volatile organic compounds. In addition, ionic liquids and salts have tunable physical and chemical properties. Energetic materials release large amount of energy when they decompose. In the case of explosives all energy is released rapidly while in the case of fuels the energy is released in a controlled manner. These materials derive their energy content from oxidation of the carbon backbone or from their high positive heats of formation. The general requirements for energetic materials are high energy and density, thermal stability, low sensitivity to impact and low toxicity. Traditional energetic materials that are commonly used in explosive formulations are HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane), RDX (1,3,5-trinitro-1,3,5-triazacyclohexane) and TNT (2,4,6, trinitrotoluene). Hydrazine derivatives are widely used as energetic fuel in rocket propulsion systems. Most recently several energetic ionic liquids have been proposed as high-energy materials, propellants and explosives. A large number of ionic salts and ionic liquids that are based on a triazole derivative have been proposed as energetic materials. 1,2,4 triazole and 1,2,3 triazole have heats of formation values of 109 KJ/mol and 272 KJ/mol respectively.

In this work we use environmental life cycle assessment method to study the environmental impact associated with the production of ionic liquids and ionic salts to compare with the environmental impact of common energetic material such as TNT. This will provide insights into whether the newer energetic materials that are currently being designed are indeed environmentally friendly as being assumed.