Potassium Picrate

Potassium picrate, or potassium 2,4,6-trinitrophenolate, is an organic chemical, a picrate of potassium. It is a reddish yellow or green crystalline material. It is a primary explosive. Anhydrous potassium picrate forms orthorhombic crystals.

Potassium picrate was first prepared as impure in mid-17th century by Johann Rudolf Glauber by dissolving wood in nitric acid and neutralizing with potassium carbonate. It is commonly made by neutralizing picric acid by potassium carbonate. It was used since 1869. Its chief applications are in pyrotechnics, in some whistle mixes, as a component of explosives (with potassium nitrate and charcoal), propellants (with potassium chlorate), and explosive primers (with lead picrate and potassium chlorate). Potassium picrate is not a very powerful explosive. It is somewhat shock-sensitive. In contact with flame it deflagrates with a loud sound. If ignited in confined space, it will detonate. It is more sensitive than picric acid.

In contact with metals (e.g. lead, calcium, iron), potassium picrate, like ammonium picrate and picric acid, forms picrates of said metals. These are often more dangerous and more sensitive explosives. Contact with such materials therefore should be prevented.

Potassium picrate is used to determine the concentration of nonionic surfactants in water; materials detectable by this method are called potassium picrate active substances (PPAS).