Picric acid
Picric acid is the chemical compound formally called 2,4,6-trinitrophenol (TNP). This yellow crystalline solid is one of the most acidic phenols and is vinylogous to nitric acid. Like other highly nitrated compounds such as TNT, picric acid is an explosive. Its name comes from Greek πικρος (pik' ros), meaning "bitter", reflecting its bitter taste.
Its primary use, now outdated, is as an explosive. It has also been used in medicine (antiseptic, burn treatments), dyes, and as a chemistry agent.
History
Picric acid was probably first mentioned in the alchemical writings of Johann Rudolf Glauber in 1742. Initially, it was made by nitrating substances such as animal horn, silk, indigo, and natural resin, the synthesis from indigo first being performed by Peter Woulfe in 1771. Its synthesis from phenol, and the correct determination of its formula, were successfully accomplished in 1841. Not until 1830 did chemists think to use picric acid as an explosive. Before then, chemists assumed that only the salts of picric acid were explosive, not the acid itself. In 1871 Hermann Sprengel proved it could be detonated and most military powers used picric acid as their main high explosive material. Picric acid is also used in the analytical chemistry of metals, ores, and minerals.
