Organic geminal hydroperoxides as potential explosives

High explosives are metastable pure substances/mixtures capable (under the right stimuli) of releasing large quantity of energy in the form of heat, light and work into the surrounding. Most practical high explosives in use today are formed from the element carbon, nitrogen, hydrogen and oxygen (e.g., TNT, PETN, HMX, etc..). In recent years, high nitrogen content explosives become more an more important due to the fact that these molecules are capable of storing large amount of potential energy (i.e. large positive heat of formations, HOF's). In high nitrogen content molecules, nitrogen is bonded to another nitrogen atom through the formation of single and double covalent bonds and thus upon detonation the nitrogen forms the highly stable, triple-bonded nitrogen molecule (N₂) with the release of high quantity of energy.

On the other hand, other class of explosives didn't find their ways into practical applications due to their poor detonation performance and their inherent instability. One example is peroxide-base explosives. Peroxide explosives (compounds containing -O-O- linkage) such as diacetone diperoxide (DADP), triacetone triperoxide (TATP), hexamethylene triperoxide diamine (HMTD) are very popular among amateur chemist but these explosives possesses low detonation performance and also high sensitivity toward impact, friction and electrostatic discharge. A recent study, shows that compounds containing the -O-O- linkage like hydroperoxides (-O-O-H) may be useful as powerful explosives and acceptable sensitivity [1].

A series of geminal hydroperoxides were synthesized from their corresponding ketones or aldehydes (see Fig.1) and 30-50 wt% hydrogen peroxide (H₂O₂) in the presence of molecular iodine (I₂) or hydrogen chloride as catalyst:



The structure of the organic hydroperoxides along with their density and detonation performance is shown in Fig.2:



As can be seen in Fig. 2, these new hydroperoxides possess acceptable calculated detonation performance (i.e. calculation done with EXPLO 5 thermochemical code) ranging from 6.15-7.13 km/s for detonation velocity and 117-119 kbar to detonation pressure. Compound (IV) is even more performant than TNT (D= 6.95 km/s, P= 190 kbar at d= 1.640 g/cm³ [2]).

It is also clear that all these hydroperoxides are denser and more powerful explosives than the well known TATP [1] (D= 5.3 km/s at d= 1.180 g/cm³). Moreover, the measured impact sensitivity (impact sensitivities were obtained on a BAM drophammer [1]) of compound (I-V) is less than that of TATP (impact sensitivity= 1-3 Joules for compound (I-V) vs 0.18 Joules for TATP).

The electrostatic discharge (ESD) value of TATP is equal to 0.16 Joules. All the hydroperoxides (except compound (III)) have ESD> 0.2 Joules.

In conclusion, these new hydroperoxides shows that compounds containing the -O-O- explosophoric moiety can be used at least as powerful primary explosives.

References:

[1] N.-D. H. Gamage; B. Stiasny; J. Stierstorfer; P. D. Martin; T. M. Klapotke; C. H. Winter, Less sensitive oxygen-rich organic peroxides containing geminal hydroperoxy groups,Chem. Commun. 51 (2015) 13298-13300.

[2] C. L. Mader, Numerical modeling of explosives and propellants, CRC, Boca Rato (Fla.), 2008.

Dany.


[Edited on 27-8-2015 by Dany]