The chemical compound trinitrotoluene (C7H5N3O6), or most commonly known as TNT, was developed in Germany in 1863 by Joseph Wilbrand. While TNT is not as powerful as dynamite, it is more stable than most explosives. For more than a century, militaries around the world have melted down TNT into shell casings for kinetic energy weapons. TNT is considered the premier mixture of chemicals for creating spectacular explosions, and it is used in the formulation of determining the amount of energy released when a nuclear weapon is detonated, usually expressed as a TNT equivalent.
After more than a 100 years of dominance, new research from the Los Alamos National Laboratory and the Army Research Laboratory have discovered a new, more powerful compound, Bis-oxadiazole (C6H4N6O8), which could render TNT obsolete.
The molecular structure of Bis-oxadiazole. (Source: OPR&D)
“It would be about 1.5 times the power of TNT,” said David Chavez, an explosives chemist at Los Alamos who worked on the new molecule, who spoke with Popular Mechanics. “So fairly energetic, quite a nice improvement compared to TNT.”
Popular Mechanics first uncovered the report titled “Bis(1,2,4-oxadiazole) Bis(methylene) Dinitrate: A High-Energy Melt-Castable Explosive and Energetic Propellant Plasticizing Ingredient,” which was published late last month in the Organic Process Research & Development, a peer-reviewed scientific journal published by the American Chemical Society.
Chavez told Popular Mechanics that TNT is a blend of the seemingly harmless elements carbon, hydrogen, nitrogen, and oxygen (C7H5N3O6). However, he compares the explosive compounds to gasoline, indicating that rather than extracting oxygen from the air to work as an oxidizer for combustion, like an engine, the explosives have all the ingredients for a powerful explosion within the compound.
The report goes on to explain how TNT has a “major advantage” on the production line than other forms of explosives: it is melt-castable, which means the explosive can be shaped into molds and shells to produce bombs.
“The place where you see it used most is mortar shells and artillery shells,” said Jesse Sabatini, a synthesis chemist with the Army Research Laboratory (ARL) at Aberdeen Proving Ground, Maryland, told Popular Mechanics.
TNT has some significant disadvantages that have led to a “quest to develop new melt-castable explosives,” said Sabatini, between various governmental agencies, including the Department of Energy and the Department of Defense. Sabatini told Popular Mechanics the Army is concerned that TNT and other chemical compounds produce high amounts of pollutants during the manufacturing process.
“There is actually quite a bit of waste that’s generated by making TNT,” Chavez said. “There’s something that’s called red water, which is the kind of water that’s left over from the nitration of TNT. And then when the TNT itself is actually isolated, it’s washed with more water, and that water is a waste that’s called pink water, and it also has some environmental impacts.”
Explosives chemist David Chavez pours an example of melt-castable explosive into a copper mold at Los Alamos National Laboratory’s Technical Area 9. (Source: Army)
“The Army always wants to have enhanced performance,” Sabatini said. “They want more blast. They want more power. And TNT is okay… but we want to do better than that.”
In 2016, ARL synthesized Bis-isoxazole, which proved to be much greener to manufacture and melt-castable, but there was one problem: the new explosive was not as powerful.
The scientist at ARL contacted their colleagues at the Los Alamos laboratories to tweak the explosive recipe. By exchanging a carbon atom for another nitrogen, the Los Alamos scientists were amazed the new tweaked compound produced a much higher explosive yield.
The result, well, the new tweaked chemical compound could replace TNT, is now known as Bis-oxadiazole.
“The additional nitrogen adds density to the molecule, and removing carbon helps balance out the oxidizer so all of the fuel can be used up to produce energy in the reaction. And once the researchers had synthesized it in the lab, they realized Bis-oxadiazole has a melting point around that of TNT, making it melt-castable,” said Popular Mechanics.
According to the scientist, there are two methods in measuring the energy of an explosion: detonation velocity and detonation pressure. It is believed that Bis-oxadiazole “should have a detonation velocity of around 8.18 km/s and detonation pressure of 29.4 gigapascals, compared to around 7.8 km/s and 26 gigapascals for Composition B,” said Popular Mechanics.
The scientist told Popular Mechanics that the production of Bis-oxadiazole would continue for future toxicity studies at ARL and Aberdeen Proving Ground. If the outcomes are successful, the new compound will be molded into artillery shells for testing at Aberdeen Proving Ground. If all goes well on the artillery range, then scientist could start producing large quantities
Chavez explained the average time from chemical discovery to fielding new explosives takes about 5 to 10 years. However, if the new explosive material is as powerful and green to manufacture as scientist suggest, then the Pentagon could rush to incorporate Bis-oxadiazole on the modern battlefield.
“It is a compound that certainly has us excited,” Sabatini said.
To sum up, the Army has developed environmentally friendly explosives that are much more powerful than TNT. It is likely this new technology of advanced explosives will be rushed onto the battlefield before the next round of wars. Seems like the Army is going green…