Picric acid

Picric acid, also known as 2,4,6-trinitrophenol (TNP), is a chemical compound with the formula C6H2(NO2)3OH. It is one of the most acidic phenols. Like other highly nitrated compounds such as TNT, picric acid is an explosive.

History

Picric acid was first synthesized in 1771 by Peter Woulfe, an Irish chemist, by the action of nitric acid on indigo. Its name comes from the Greek word pikros, which means bitter, due to its bitter taste.

Properties

Picric acid is a yellow crystalline solid, which is odorless when dry but has a strong, unpleasant odor when wet. It is slightly soluble in water and more so in ethanol. It is highly sensitive to shock and friction, making it a powerful explosive.

Uses

Picric acid has been used for many purposes throughout history. It was used as a yellow dye in the 19th century. In the early 20th century, it was used as an antiseptic and a treatment for burns. Today, it is primarily used in laboratories for the preparation of picrate salts, which are used in the analysis of metals.

Safety

Due to its explosive nature, picric acid must be handled with care. It should be stored in a cool, dry place, away from sources of ignition. It should not be allowed to come into contact with metals, as this can form highly sensitive picrate salts.

See also

• Explosive material
• Phenol
• Peter Woulfe

References

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  Chemical structure of Picric acid
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  Picric acid crystals
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  French munitions industry during World War I
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  Stumps and rocks being removed by Picric acid