TriNitroToluene (TNT), the Mistaken Dynamite.

Background of TNT

Yellow dye from TNT

2, 4, 6 - Trinitrotoluene (TNT) with the molecular formula of C₇H₅N₃O₆  is entirely different compound from dynamite. TNT has an interesting starting point where it was originally developed as a dye, not an explosive! 

Julius Wilbrand a.k.a Joseph Wilbrand

TNT revolutionized civil engineering and has cemented itself in the public consciousness as the definition of explosives. TNT was invented in 1863, just four years before dynamite by a German chemist named Julius Wilbrand also known as Joseph Wilbrand. Interestingly enough, TNT’s intended purpose was to act as a yellow dye. Its explosive capabilities weren’t even realized until years after its invention. Its explosiveness weren’t noticed because it has fairly high activation energy. In addition to that, it was actually less powerful than alternative explosive compounds of the day.

Properties of TNT

TNT is powder

TNT is a yellow, odorless solid that does not occur naturally in the environment. It has a melting point of 80.1°C and boiling point of 240°C. It is commonly used as an explosive in military shells, bombs and grenades, in industrial uses, and in underwater blasting. TNT may be burned but it is difficult to ignite. When water has been driven off or evaporated, the residue is easily ignited and it burns vigorously and is highly explosive. TNT also produces toxic oxides of nitrogen during combustion.

TNT in chunks

Safety and toxicity of TNT

TNT is poisonous, and skin contact can cause skin irritation. It causes the skin to turn into a bright yellow-orange color. During the First World War, workers who handled TNT found their skin turned bright yellow which resulted in them acquiring the nickname of “canary girls” or simple “canaries”.

People who are exposed to TNT over a prolonged period tend to experience anemia and abnormal liver functions. Blood and liver effects, spleen enlargement and other harmful effects on the immune system have also been found in animals that ingested or breathed TNT. There is evidence that TNT adversely affects male fertility. TNT is listed as carcinogenic as its effects are tested on lab rats. 

Consumption of TNT produces red urine through the presence of breakdown products and not blood as sometimes believed. 

Symptoms of Anemia

TNT may cause contamination called “pink water” as it was found that some military testing grounds’ wastewater are contaminated by the TNT and appeared as pink in color.

Advantages of TNT

Prior to the development of TNT, explosives were highly instable and prone to near-spontaneous combustion where they are easily exploded. Compounds such as black powder and nitroglycerine were often used, sometimes in volatile multi-compound mixtures. These compounds stated were highly explosive but the major and severe drawback is they have low activation energies. In other words, these explosives could be combust accidentally without ignition. In fact, there were cases where the shipment of the compounds above exploded and killed many people.  

TNT’s stable character made it a good choice for construction operations such as rock-blasting. Besides that, TNT has a melting point which is well below the temperature at which it spontaneously combusts. This allows manufacturers to safely pour the compound in liquid form. Additionally, TNT does not dissolve nor absorb water, making it safe to use in wet environments.

TNT has also helped in the military forces in developing weapons ever since 1902 when German forces began using TNT in their artillery shells. These shells were able to pass through British ships’ armor prior to exploding. In other words, the artillery shells tend to pierce or break the armor before exploding. Thus, TNT-containing shells were able to wreak havoc on contemporary ships by dumping a huge portion of their energy inside of the target.

TNT is also widely used alongside dynamite in the construction of the American railroad system. During this construction, there often are paths that required passage through a whole mountain, and so TNT and dynamite were brought in by the ton to clear passageways.

M795 projectile with IMX-101

Disadvantages of TNT

Though TNT is relatively stable, it does have some drawbacks. Explosives which contain TNT can degrade when stored at high temperatures. This in turn may create cracks in the explosive, increasing its shock sensitivity. Additionally, TNT’s energy density is somewhat low for an explosive compound. TNT was replaced by a compound called IMX-101 in the US army artillery shells as IMX-101 is less shock-sensitive and more stable in high temperatures.

Here's a compiled footage of TNT explosions.