S. Mudi Mannan

Abstract: Energetic salts offer many advantages over conventional energetic molecular compounds. The use of nitrogen containing anions and cations contributes to high heats of formations and high densities. Their low carbon and hydrogen content gives rise to a good oxygen balance. The decomposition of these compounds is predominantly through the generation of dinitrogen which makes them very promising candidates for highly energetic materials for industrial or military applications.

Abstract: Energetische Salze bieten zahlreiche Vorteile gegenuber herkommlichen energetischen Molekulverbindungen. Die Verwendung von stickstoffhaltigen Kationen und Anionen tragt zu hoheren Bildungswarmen und Dichten bei, wobei durch den niedrigen Gehalt an Kohlenstoff und Wasserstoff auch eine gute Sauerstoffbilanz erzielt wird. Da bei der Zersetzung dieser stickstoffreichen Verbindungen ein groserer Anteil von Distickstoff entsteht, sind sie vielversprechende hochenergetische Materialien fur technische und militarische Anwendungen.

Abstract: 2,4,5-Trinitroimidazolate (TNI) salts with "high-nitrogen" cations tend to be highly hydrogen bonded and have heats of formation ranging up to 616 kJ mol(-1). Density, oxygen balance, and thermostability are enhanced by the presence of TNI. Based on theoretical calculations, all of the new salts are potential propellants.

Abstract: The widespread and long-term use of TNT has led to extensive study of its thermal and explosive properties. Although much research on the thermolysis of TNT and polynitro organic compounds has been undertaken, the kinetics and mechanism of the initiation and propagation reactions and their dependence on the temperature and pressure are unclear. Here, we report a comprehensive computational DFT investigation of the unimolecular adiabatic (thermal) decomposition of TNT. On the basis of previous experimental observations, we have postulated three possible pathways for TNT decomposition, keeping the aromatic ring intact, and calculated them at room temperature (298 K), 800, 900, 1500, 1700, and 2000 K and at the detonation temperature of 3500 K. Our calculations suggest that at relatively low temperatures, reaction of the methyl substituent on the ring (C-H alpha attack), leading to the formation of 2,4-dinitro-anthranil, is both kinetically and thermodynamically the most favorable pathway, while homolysis of the C-NO(2) bond is endergonic and kinetically less favorable. At approximately 1250-1500 K, the situation changes, and the C-NO(2) homolysis pathway dominates TNT decomposition. Rearrangement of the NO(2) moiety to ONO followed by O-NO homolysis is a thermodynamically more favorable pathway than the C-NO(2) homolysis pathway at room temperature and is the most exergonic pathway at high temperatures; however, at all temperatures, the C-NO(2) --> C-ONO rearrangement-homolysis pathway is kinetically unfavorable as compared to the other two pathways. The computational temperature analysis we have performed sheds light on the pathway that might lead to a TNT explosion and on the temperature in which it becomes exergonic. The results appear to correlate closely with the experimentally derived shock wave detonation time (100-200 fs) for which only the C-NO(2) homolysis pathway is kinetically accessible.

Abstract: Many advantages accrue from nitrogen-rich heterocyclic compounds compared to traditional molecular energetic compounds. Utilization of heterocyclic nitrogen-containing cations and anions in energetic salts gives rise to lower vapor pressures, higher heats of formation and higher densities. Additionally, smaller amounts of hydrogen and carbon contribute to a better oxygen balance than normally is found with their carbocyclic analogues. Nitrogen-rich compounds are promising high energetic materials that may be more acceptable than their alternatives for both industrial and military uses since a higher percentage of their decomposition products will be dinitrogen.