- The project consisted with combining CL-20 and N2O4.
- For ideal characteristics, the explosive should contain an equal amount of oxidizer and reducing agent.
- The entire process was recorded on a high-speed video camera, so that the speed of the combustion front could be calculated later.
Russian scientists, in collaboration with their Chinese colleagues, created one of the most powerful explosives yet discovered. The project was done conjointly between the the Russian Mendeleev University of Chemical Technology and the Beijing Institute of Technology.
The project consisted of combining CL-20 and an active oxidizer of the N2O4 into one. There are many explosives and the CL-20 is one of the most powerful. Its detonation speed is about 9.5 km/s, while that of TNT reaches only 7 km/s.
Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide, which is usually used by ex-USSR/Russia rocket engineers, as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium mixture with nitrogen dioxide.
It is a consensus that an energy-saturated material consists of a fuel and an oxidizer. For ideal characteristics, the explosive should contain an equal amount of oxidizer and reducing agent. However, in real molecules, including CL-20, the oxidizer is always less.
As Valery Sinditski, a Professor at the Russian State Technical University, said:
“We wanted to add an additional oxidizer to CL-20 to improve its energy, and some crystal modifications of this molecule have internal cavities in its structure. We filled them with an extremely aggressive compound, nitrogen tetraoxide N2O4. This is a very strong oxidizer, which is widely used in liquid rocket fuels and when it comes into contact with an organic compound, a rapid oxidation-reduction reaction usually begins. However, the CL-20 molecules themselves contain so many NO2 groups that they simply do not react with this oxidizer and serve as a vessel for such an aggressive compound.”
Moreover, to modify CL-20, the scientists took its crystals, dissolved them at room temperature in chloroform, and added liquid N2O4. Then, from this mixture, CL-20 crystallized with already captured oxidizer molecules. Thereafter, the scientists examined the structure of the resulting compounds and found that N2O4 was actually embedded in the cavities of the CL-20 crystal.
In this case, over time, the N2O4 molecules dissociate to even more active compounds: NO2 radicals, and the initially white crystals become brownish along with this. Next, the researchers conducted a series of experiments on thermal decomposition and combustion of new compounds.
It should be noted that CL-20 was not blown up, but carefully burned, as this allows us to reliably assess the technical characteristics of the explosive. The charge from the modified CL-20 was pressed into thick-walled plexiglass tubes and ignited, and the temperature distribution in the combustion wave was recorded using built-in thin thermocouples.
At the same time, the entire process was recorded on a high-speed video camera, so that the speed of the combustion front could be calculated later. It has been found that the combustion rate of the new substance exceeds the same value for pure CL-20 in the same crystal modification, and the thermal stability is comparable.
From other data obtained, the scientists estimated the detonation rate of the new substance and the pressure in the shock wave from its explosion and showed that the modified CL-20 even exceeds the pure CL-20 in these parameters.
Prior to this work, other research groups have already had similar studies with CL-20 solvates— that is, CL-20 molecules in the cavity of the crystal structure of which any liquids are enclosed, but no one has yet tried to combine CL-20 with N2O4.
The work titled “Solvate of 2,4,6,8,10,12‐Hexanitro‐2,4,6,8,10,12‐Hexaazaisowurtzitane (CL‐20) with both N2O4 and Stable NO2 Free Radical” is available here.
The work is a an interesting combination. Nevertheless, it is very dangerous creation.