Trinitrotoluene

Trinitrotoluene (TNT) is a chemical compound with the formula C₆H₂(NO₂)₃CH₃. This yellow-coloured solid is a reagent in chemistry but is best known as a useful explosive material with convenient handling properties. The explosive yield of TNT is considered the standard measure of strength of bombs and other explosives (see TNT equivalent). In chemistry, TNT is used to generate charge transfer salts.

1 Explosive character
2 Toxicity
3 Use
4 History
5 Preparation
6 Difference from dynamite
7 See also
8 External links

[edit] Explosive character

Upon detonation, TNT decomposes as follows:

2 C₇H₅N₃O₆ →3 N₂ + 5 H₂O + 7 CO + 7 C

The reaction is exothermic, but has a high activation energy. Because of the production of carbon, TNT explosions have a sooty appearance. The following data characterize the detonation of TNT.

property	value
Shock sensitivity	Insensitive
Friction sensitivity	Insensitive
RE factor	1.00
Explosive velocity	6,900 m/s (density: 1,6 g/cm³)
Steam pressure at 20 °C	150 to 600 Pa
Lead block test	300 ml/10 g
Sensitivity to impact	15 N·m
Friction sensitivity	to 353 N (36 kp) no reaction

[edit] Toxicity

TNT is poisonous and skin contact can cause skin irritation, causing the skin to turn a bright yellow-orange color.

People 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 trinitrotoluene. There is evidence that TNT adversely affects male fertility, and TNT is listed as a possible human carcinogen. Consumption of TNT produces black urine.

During the First World War, munition workers who handled the chemical found that their skin turned bright yellow, which resulted in their acquiring the nickname "canary girls" or simply "canaries." TNT also slowly changes ginger-coloured hair to green. A 1916 British Government inquiry on female workers at the Royal Arsenal, Woolwich found that 37% had severe pains due to loss of appetite, nausea, and constipation, 25% suffered from dermatitis, and 34% experienced changes in menstruation. Before respirators and protective grease applied to the skin were introduced, about 100 workers died from the disease.^{[citation needed]}

Some military testing grounds are contaminated with TNT. Wastewater from munitions programs including contamination of surface and subsurface waters may be colored pink due to the presence of TNT and RDX. Such contamination, called “pinkwater,” may be difficult and expensive to remedy.

[edit] Use

TNT is the most common explosive for military and industrial purposes. It is valued due to its insensitivity to shock and friction, which reduces the chance of an unexpected detonation. TNT melts at 80 °C, far below the temperature at which it will spontaneously detonate, allowing it poured as well as safely combined with other explosives. TNT also does not absorb water or dissolve easily in it, allowing it to be used effectively in wet environments.

[edit] History

TNT was first prepared in 1863 by a German chemist Joseph Wilbrand and originally used as a yellow dye. Its potential as an explosive was not appreciated for several years mainly because it was so difficult to detonate and because it was less powerful than alternatives. Among its advantages, however, TNT can be safely melted using steam or hot water, allowing the liquid to be poured into shell cases. It is also so insensitive that, for example, in 1910, TNT was exempted from the UK's Explosives Act 1875, i.e. it was not considered an explosive for the purposes of manufacture and storage.

The German armed forces adopted it as a filling for artillery shells in 1902. TNT-filled armour-piercing shells would explode after they had penetrated the armour of British capital ships, whereas the British lyddite-filled shells tended to explode upon striking armour, thus expending much of their energy outside the ship. The British started replacing lyddite with TNT in 1907.

Because of the high demand for explosives during the Second World War, TNT was frequently mixed with 40%-80% ammonium nitrate, producing an explosive called amatol. Although nearly as powerful as TNT (and much less expensive), amatol suffered from the slight disadvantage of being hygroscopic (prone to absorbing water). Another variation called minol, consisting of amatol mixed with about 20% aluminium powder, was used by the British in mines and depth charges. Although blocks of pure TNT are available in various sizes (e.g. 250, 500, and 1000 g) it is more commonly encountered in explosive blends that comprise a variable percentage of TNT plus other ingredients. Examples of explosive blends containing TNT include

[edit] Preparation

TNT is synthesized in a two-step process. First, toluene is nitrated with a mixture of sulfuric and nitric acid to produce mono- and dinitrotoluene. Next, the mixture of mono- and dinitrotoluene is further nitrated with a mixture of nitric acid and oleum, a more potent nitration recipe. The waste acid from this second step can be recycled for use in the first.

[edit] Difference from dynamite

It is a common misconception that TNT and dynamite are the same, but this is not the case. Whereas TNT is a specific chemical compound, dynamite is a type of wood pulp or another absorbent mixture soaked in nitroglycerin that is compressed into a cylindrical shape and wrapped in paper.