Energetic Materials Laboratory
Department of Chemistry
Indian Institute of Technology Kanpur, India
Dr. Srinivas Dharavath
Assistant Professor
Our research group design and synthesis various nitrogen rich azoles, fused and strained ring containing small molecules which are highly dense, thermally stable and insensitive towards mechanical stimuli for 'Green' and 'Environmentally friendly' high energy materials (HEM) applications. So far, we have synthesized various poly-nitrogen containing small energetic molecules and salts from cheap and commercially available starting materials as HEM in a simple and straightforward manner. Few of the synthesized molecules are a better replacement for the existing benchmark energetic materials that meet the requirements of present and future civil, defence and space missions.
To develop environmental-friendly green energetic materials with excellent insensitivity, thermal stability, and detonation performances, a series of nitrogen-rich salts were synthesized from di(1H-tetrazol-5-yl) methane and N,N'-(methylenebis (1H-1,2,4-triazole-3,5- diyl))dinitramide in a simple and straightforward high-yield approach. The molecules were characterized by NMR, IR, elemental analyses, and differential scanning calorimetry. Single crystal X-ray diffraction studies confirm the molecular structures of salts 4 and 15. Their key energetic parameters, viz., energy content, densities, detonation performances, melting and decomposition temperatures, and impact/friction sensitivities, were assessed. All of these salts disclosed excellent thermal stabilities over 210 °C as measured by DSC. The crystal structure of compounds 4 and 15 shows strong intramolecular network of hydrogen-bonding expected to stabilize the salts and induce higher insensitivity to mechanical stimuli. All the newly synthesized derivatives exhibit superior energetic performance over TNT, close to RDX. The salts 5, 6, 10-14, and 16 display properties better than TATB and are expected to serve as potential energetic materials
The oxadiazole ring is an essential nitrogen-containing heterocycle and valuable building blocks in developing numerous functionalized energetic compounds. Intending to understand the effect of multiple oxadiazole rings on the energetic performance and sensitivities, oxadiazole rings connected with C–C and N=N bond possessing –NO2 and
–NHNO2 groups have been investigated. The results show that incorporating oxadiazoles in the skeleton is very valuable for improving its energy content. All the studied compounds have positive heat of formation (> 410 kJ/mol) and larger than those of 3,4-dinitrofurazan (O1, 219 kJ/mol) and N,N'-1,2,5-oxadiazole-3,4-diyldinitramide (O7, 254 kJ/mol). Even though various molecular combinations offer unlimited structural diversity options and energetic properties, the linear addition of oxadiazole rings efficiently reduces sensitivity but with decreased oxygen balance and detonation performance. To achieve the balance between sensitivity and detonation performance, incorporating oxadiazole rings in the molecular framework may be considered as an efficient scaffold and can significantly assist in the progress of new energetic compounds.