TEX (chemical name 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo .5.0.0^5,9.0^3,11dodecane) is a dense (ρ = 1.985 g cm⁻³)

nitramine Nitramide is a chemical compound with the molecular formula H2NNO2. Organyl derivatives of nitramide, RNHNO2 are termed nitroamines, and are widely used as explosives: examples include RDX and HMX. It is an isomer of hyponitrous acid. Struct ...

high explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

, that derives from the very powerful and sensitive high explosive

CL-20 Hexanitrohexaazaisowurtzitane, also called HNIW and CL-20, is a polycyclic nitroamine explosive with the formula C6H6N12O12. In the 1980s, CL-20 was developed by the China Lake facility, primarily to be used in propellants. It has a better oxid ...

. Though related to CL-20 in that is shares the same cage structure, TEX is more easily synthesized in good yield from inexpensive starting materials. Unlike CL-20, TEX is friction insensitive, bears a low impact sensitivity, and possesses a very low shock sensitivity and large critical diameter, making it an interesting explosive filler for

insensitive munitions Insensitive munitions are munitions that are designed to withstand stimuli representative of severe but credible accidents. The current range of stimuli are shock (from bullets, fragments and shaped charge jets), heat (from fires or adjacent ther ...

. Its systematic name, 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo .5.0.0^5,9.0^3,11dodecane derives from its tetracyclic structure.

Synthesis and production

Unlike CL-20, which requires a cumbersome and even costly procedure, TEX is obtained in moderate yield (40 wt.-%) in a one-pot synthesis from 1,4-diformyl-2,3,5,6-tetrahydroxypiperazine (DFTHP) and mixed acid ( H₂SO₄/ HNO₃). The DFTHP undergoes proton-catalyzed hydrolysis and yields

glyoxal Glyoxal is an organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of ...

which reacts as with an intermediate to give TEX. : TEX-formation

Performance

Based on the Kamlet-Jacobs method, the formal idealistic detonation of TEX :C₆H₆N₄O₈ → 3 H₂O_(g) + 2CO₂ + CO + 3 C_(gr) + 2 N₂ at ambient temperature and density of TEX (1.985 g/cm³) yields a detonation velocity of 8170 m/s and a CJ pressure of 31.4 GPa. Calculations with advanced computer codes like EXPLO and CHEETAH call for even higher detonation velocity but about similar values for the detonation pressure definitely superseding insensitive high explosive NTO. Experimental determination with plastic bonded formulations at high theoretical maximum density exceed the predicted detonation pressures but fall a little short with regards to the detonation velocity if the charge diameter is below 90 mm.

Sensitivity

TEX is not friction sensitive and requires some 40 Joules energy to react in the BAM impact tester. In the autoignition test it yields a mild burn response at 252 °C onset temperature. TEX is also mildly shock sensitive in the Large Scale Gap Test (LSGT).

Toxicity

TEX has a similar water solubility as

RDX RDX (abbreviation of "Research Department eXplosive") or hexogen, among other names, is an organic compound with the formula (O2N2CH2)3. It is a white solid without smell or taste, widely used as an explosive. Chemically, it is classified as a ...

and hence will be equally mobile in soil and groundwater. However, in comparison to insensitive explosive NTO, which is highly soluble in water (16 g/L), it should pose a lower level of concern when considering the environmental effects of unexploded or partially exploded charges. Preliminary investigation of the effects of TEX on daphnia and cell cultures show slightly lower toxicity than RDX.

Application

Though known since 1990 TEX is still an experimental explosive. However, given its large critical diameter and low shock sensitivity, it is an ideal candidate for insensitive large-calibre ammunition such as general-purpose bombs, artillery shells, torpedo- and depth charges.

References