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Solubility Thermodynamics of Organic Energetic Materials
Published in Mark J. Mezger, Kay J. Tindle, Michelle Pantoya, Lori J. Groven, Dilhan M. Kalyon, Energetic Materials, 2017
Sanjoy K. Bhattacharia, Nazir Hossain, Brandon L. Weeks, Chau-Chyun Chen
Organic energetic materials are extensively used in industrial, mining, propulsion, and military applications. Pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), and cyclotetramethylenetetranitramine (HMX) are among the most commonly used organic energetic materials. Molecular structures of PETN, RDX, and HMX are shown in Figure 3.1 (NIST webbook 2016). Synthesis of PETN, RDX, and HMX is carried out in solution, and pure forms of these materials are obtained by crystallization of the solution (Akhavan 2004). For proper selection of solvents and antisolvents and calculation of the rate of crystallization, knowledge of the solubility in pure and mixed solvents is essential. Likewise, assessment of the environmental fate of these energetic materials requires knowledge of their solubilities in water. However, measuring the solubilities of energetic materials in various solvents and mixed solvents can be very expensive and time consuming.
Formation of Nanosized Aluminum and Its Applications in Condensed Phase Reactions
Published in Claudia Altavilla, Enrico Ciliberto, Inorganic Nanoparticles: Synthesis, Applications, and Perspectives, 2017
Jan A. Puszynski, Lori J. Groven
During the past decade, a significant research effort has been made to understand the reactivity of elemental nanopowders, such as aluminum, boron, silicon, and several transition metals with different oxidizers. The research effort has also been on investigation of these fuel particles as an energetic enhancement of secondary energetic systems. Energetic materials are a subclass of reactive materials containing both fuel and oxidizer. These materials can be further classified as homogeneous or heterogeneous systems, depending on whether the oxidizer is chemically or physically linked to the fuel. These types of energetic materials are commonly used as propellants, explosives, or pyrotechnics. Homogeneous energetic materials are based on monomolecular compounds, such as TNT, RDX, HMX, and CL-20 (Dreizin 2009). The maximum energy released by these compounds during the combustion process is 50%–500% lower than the energy generated by the combustion of elemental reactants. For example, the oxidation of aluminum or boron generates approximately 30 kJ/g or 58 kJ/g, respectively, compared to 10 kJ/g for HMX energetic material. In order to take advantage of the large energy associated with the oxidation of elemental powders in energetic systems, it is necessary to increase the combustion front velocity by two to three orders of magnitude. Traditionally used micron-sized powders in thermite mixtures are characterized by very low combustion front velocities, only a few meters per second. Therefore, efforts to reduce the average particle size of a fuel reactant are necessary to obtain much faster reaction rates.
Explosives
Published in Per-Anders Persson, Roger Holmberg, Jaimin Lee, Rock Blasting and Explosives Engineering, 2018
Per-Anders Persson, Roger Holmberg, Jaimin Lee
The term energetic material is mostly used to comprise all materials that can undergo exothermal chemical reaction releasing a considerable amount of thermal energy. A wider definition is sometimes used to include inert materials at high pressure and/or high temperatures. It includes in the concept of energetic material any material that has a high internal energy because it is compressed to a high pressure and/or heated to a high temperature. A high pressure gas in a pressure vessel by this definition is an energetic material, which seems logical. The white-hot tungsten filament in a lamp bulb could also, with the wider definition, be termed an energetic material. It would be an example of an energetic material that is not explosive because, even at that high temperature, tungsten is still a solid and does not expand, except very slightly due to thermal expansion. By contrast, the nickel bridge wire in an exploding bridge wire (EBW) detonator, heated into its gaseous supercritical state by a short-duration, high-energy, high-voltage electric discharge, would be an example of an explosive energetic material, although no chemical reaction is involved in releasing the energy. The vaporized bridge wire material expands explosively, shock initiating the secondary explosive of the detonator, pressed into contact with the bridge wire. Yet another example of an energetic material that is not explosive in itself is a pyrotechnic material mix. An example of a pyrotechnic material is thermite, an intimate finely powdered mix of iron oxide, Fe2O3, with aluminum. Thermite reacts chemically with the release of thermal energy sufficient to heat the resulting mix of Fe and Al2O3 to an intensively luminous white hot, but even the Fe is in the condensed state, and the hot reaction products therefore do not expand explosively. In the following, we will mostly use the term energetic material to mean explosives, propellants, and pyrotechnics.
Effect of heating rates on the energy release application of Al/MLG/Fe2O3 nanothermite
Published in Philosophical Magazine, 2023
Priya Thakur, Vimal Sharma, Nagesh Thakur
Energetic materials are materials that store chemical energy and release it by an exothermic redox (oxidation–reduction) reaction between the constituents. These materials are further categorised into two classes i.e. monomolecular and binary energetic materials. In monomolecular energetic materials, constituent particles are present in the same molecule. The energy release rate of such materials is fast whereas the density of released energy is low due to the less interfacial contact and mass transport between the reactants. On the other hand, the fuel and oxidisers are separate molecules in binary composites (thermite) having more density of released energy but less energy release rate. The Al/Fe2O3 is the first thermite discovered by Goldschmidt in 1895 for the application of welding railway tracks. The redox reaction in the Al/Fe2O3 composite material available in the literature is [1–3]:
Cocrystallization of energetic Mn(II) complex with nitrogen-rich ligand SCZ and oxygen-rich ligand TNR
Published in Journal of Coordination Chemistry, 2019
Guo-Ying Zhang, Li Yang, Wen-Chao Tong, Ji-Min Han, Nai-Meng Song
Energetic materials that can store and release substantial amounts of chemical energy are extensively used in military and civilian areas [1]. The development of energetic materials still focuses on exploring new energetic compounds of excellent performance [2]. The most studied topic in the preparation of energetic compounds is the facile synthesis of new energetic complexes [3]. However, as the structures and synthetic procedures of new ligands becoming more and more complicated [4], the synthetic difficulties and high costs of novel ligands may limit their practical application. Cocrystallization is an effective method to alter and improve the properties of energetic materials [5]. Synthesis and investigation of energetic cocrystals have drawn wide attention and usually only organic energetic compounds can be used for cocrystallization [6], while reports of coordination energetic complex cocrystals are rare [7]. A possible reason lies in the requirements mismatch to generate complexes and cocrystals. The unique coordination modes of the ligands and central metals usually cannot satisfy the strict requirements on the spatial structure and interaction of components to form cocrystals simultaneously. Therefore, research on the preparation and properties of complex cocrystals is very challenging.
An overview over dinitramide anion and compounds based on it
Published in Indian Chemical Engineer, 2020
Energetic materials (EM’s) are the chemical compounds with stored chemical energy in it that can be released upon combustion. EM’s find its applications in mining, firecrackers, explosives, safety air bags, military shells and in propellants. Explosives are generally combusted in an uncontrolled fashion for creating deflagration to detonation condition rapidly in order to generate shock waves, while on the other hand solid propellants are burned in a controlled manner. Solid propellants are combusted uniformly with desired burning rate inside a solid rocket motor chamber to produce sufficient thrust for creating lift-off condition of the rockets and missiles and to defy Earth’s gravitational pull. DA-based compounds find their applications in both explosives and propellants [1,2].