I recently stumbled across a reference to toluene, and I couldn’t help but think, how hard is it to transform toluene into trinitrotoluene, or TNT? (Which has an interesting history…)
TNT was first prepared in 1863 by German chemist Julius Wilbrand and originally used as a yellow dye. Its potential as an explosive was not recognized for three decades, mainly because it was too difficult to detonate and because it was less powerful than alternatives. Its explosive properties were first discovered by another German chemist, Carl Häussermann, in 1891. TNT can be safely poured when liquid into shell cases, and is so insensitive that it was exempted from the UK’s Explosives Act 1875 and 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.
The process for making TNT is simple, but not easy:
In the laboratory, 2,4,6-trinitrotoluene is produced by a two-step process. A nitrating mixture of concentrated nitric and sulfuric acids is used to nitrate toluene to a mixture of mono- and di-nitrotoluene isomers, with careful cooling to maintain temperature. The nitrated toluenes are then separated, washed with dilute sodium bicarbonate to remove oxides of nitrogen, and then carefully nitrated with a mixture of fuming nitric acid and sulfuric acid.