TNT

Trinitrotoluene - TNT

TNT is an Explosive Material 2,4,6-trinitrotoluene is better known by its initials, TNT. It is an important explosive, since it can very quickly change from a solid into hot expanding gases. Two moles of solid TNT almost instantly changes to 15 moles of hot gases plus some powdered carbon, which gives a dark sooty appearance to the explosion.

TNT is explosive for two reasons. First, it contains the elementscarbon, oxygen and nitrogen, which means that when the material burns it produces highly stable substances (CO, CO2 and N2) with strong bonds, so releasing a great deal of energy. This is a common feature of most explosives; they invariably consist of many nitrogen or oxygen containing groups (usually in the form of 2, 3 or more nitro-groups), attached to a small, constricted organic backbone.

However, explosives like TNT, actually have less potential energy than gasoline, but it is the high velocity at which this energy is released that produces the blast pressure. This very high speed reaction is called a detonation. TNT has a detonation velocity of 6,940 m/s compared to 1,680 m/s for the detonation of pentane in air, and the 0.34 m/s stoichiometric flame speed of gasoline combustion in air.

The second fact that makes TNT explosive is that it is chemically unstable - the nitro groups are so closely packed that they experience a great deal of strain and hindrance to movement from their neighbouring groups. Thus it doesn't take much of an initiating force to break some of the strained bonds, and the molecule then flies apart. Typically 1 gram of TNT produces about 1 litre of gas, which is a 1000 fold increase in volume. This expanding hot gas can be used to propel a projectile, such as a bullet from a gun, or for demolition purposes.