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or Tnt Trinitrotoluene

acid, compound, sulphuric, reaction, shells and product

TRINITROTOLUENE, or TNT, Cili.(CH8) (NO,),, a high explosive, the final nitration product of toluene, is obtained by the energetic treatment of this hydrocarbon with strong nitric acid in the presence of concen trated sulphuric acid. The reaction takes place in three stages, with the formation of mono nitrotoluene and dinitrotoluene as intermediate products. The compound has also been pre pared on a large scale by dissolving orthonitro toluene in 100 per cent sulphuric acid at 60 70° C.; a mixture of nitric and sulphuric acids is allowed to run into the solution in a fine stream with constant stirring and cooling. Under these conditions the formation of dini trotoluene is indicated by a drop in temperature. In order to complete the reaction, the mixture is maintained at a temperature of 120-130° C. for one hour. An increase in yield is claimed by the addition of water to the reaction mix ture at 100° C. During the process of manu facture a number of inorganic salts are pro duced by the action of acids on nitrating cham bers; these impurities act as catalysers and pro mote the formation of nitrated cresols and other by-products, which may form unstable salts with metals, causing premature explosions. It is, therefore, necessary to prepare a compound of high purity. For this purpose the crude product is removed from the tutrators as soon as the desired reaction comes to an end, and purified by first washing with boiling water; volatile impurities are removed by keeping the compound at 95-100° C. for several hours; it is then crystallized from a mixture of 90 per cent alcohol and benzene. Patents have also been issued dealing with purification by dis solving in hot concentrated sulphuric acid and extracting the product by dilution and cooling.

The compound has further been purified by recrystallization from orthonitrotoluene.

Pure trinitrotoluene crystallizes in almost white needles which melt at 80.6° C., and pos

sess a density of 1.6. Its density may be in creased to 1.7 by melting and pouring into shells, or by allowing the molten mass to cool under pressure. It dissolves readily in alcohol, acetone, benzene, toluene, nitrotoluene, and fairly readily in hot concentrated sulphuric acid.

Although trinitrotoluene does not quite pos sess the detonating power of picric acid, in many respects it is decidedly superior to this competitor. At ordinary temperatures it is a perfectly stable explosive; it may be compressed into shells, mines, torpedoes and into slabs or cylinders with perfect safety, and the pressed charges withstand impact of high power bul lets without exploding. The compound is non hygroscopic, and its dust or vapor are not irritating. Having no acid properties it is inert in the presence of metals or their oxides. When ignited it burns with a smoky flame, and when detonated with mercury fulminate it leaves no poisonous vapors or gases, and having a much lower melting point than picric acid, it may be poured into shells at lower temperatures. On account of these properties trinitrotoluene has been extensively employed, sometimes in pref erence to picric acid, as an explosive for shells, mines, hand grenades and torpedoes. It has also been used in safety detonators. Being somewhat deficient in oxygen, it is often mixed with potassium chlorate, lead nitrate and other compounds that can supply the necessary oxygen.

Trinitrotoluene exists in six isomeric modi fications. These are of practically the same value as explosives. The commercial product usually contains the symmetrical compound (1 methyl 2, 4, 6-trinitrobenzene), although the other isomers may also be present.