The design and synthesis of modern energetic materials needs to take environmental concerns and safety issues into account. In addition to traditional criteria like density and detonation properties, environmentally benign decomposition products are also important. Traditional energetic materials that are used for military purposes and civilian applications, for example, 1,3,5-trinitrotriazacyclohexane (RDX), contain nitro functionalities. These nitro groups give good density and positive oxygen balance, but tend to lead to a decreased heat of formation and decreased stability.
Jean’ne M. Shreeve and colleagues, University of Idaho, Moscow, ID, USA, have developed an effective synthesis of N,N‘-ethylene-bridged nitropyrazoles, which show good detonation properties and molecular stability. The team found that N,N‘-ethylene-bridged diaminobis(pyrazoles) exhibit good thermal stability, low impact sensitivity, and favorable energetic performance, whereas N,N‘-ethylene-bridged dinitraminobis(pyrazoles) and diazidobis(pyrazoles) have better detonation performance, but with higher impact and friction sensitivity.
The N,N‘-ethylene-bridged hexanitrobis(pyrazole) derivative was found to be the most promising compound with high density, favorable thermal stability, and good energetic properties and may be a possible alternative to RDX.
- Energetic N,N‘-Ethylene-Bridged Bis(nitropyrazoles): Diversified Functionalities and Properties,
Ping Yin, Jiaheng Zhang, Damon A. Parrish, Jean’ne M. Shreeve,
Chem. Eur. J. 2014.