{{chembox , Verifiedfields = changed , Watchedfields = changed , verifiedrevid = 428744204 , ImageFile =Potassium picrate.svg , ImageSize = , PIN = Potassium 2,4,6-trinitrophenoxide , OtherNames = Potassium 2,4,6-trinitrophenolate; Picric acid, potassium salt , Section1={{Chembox Identifiers , CASNo_Ref = {{cascite, correct, ?? , CASNo = 573-83-1 , EINECS = 209-361-0 , UNII_Ref = {{fdacite, correct, FDA , UNII = I7I1601L00 , PubChem = 68454 , ChemSpiderID_Ref = {{chemspidercite, changed, chemspider , ChemSpiderID = 61732 , SMILES = c1c(cc(c(c1 +=O) - - +=O) - +=O) - +, InChI = 1/C6H3N3O7.K/c10-6-4(8(13)14)1-3(7(11)12)2-5(6)9(15)16;/h1-2,10H;/q;+1/p-1 , InChIKey = RBGOCSKFMWMTRZ-REWHXWOFAJ , StdInChI_Ref = {{stdinchicite, changed, chemspider , StdInChI = 1S/C6H3N3O7.K/c10-6-4(8(13)14)1-3(7(11)12)2-5(6)9(15)16;/h1-2,10H;/q;+1/p-1 , StdInChIKey_Ref = {{stdinchicite, changed, chemspider , StdInChIKey = RBGOCSKFMWMTRZ-UHFFFAOYSA-M , Section2={{Chembox Properties , Formula = C₆H₂KN₃O₇; C₆H₂(NO₂)₃OK , MolarMass = 267.194 g/mol , Density = 1.852 g/cm3 , MeltingPtC = 250 , BoilingPt = Detonates at 331 °C before boiling , Section3={{Chembox Hazards , MainHazards = Explosive and toxic , GHSPictograms = {{GHS01{{GHS06 , GHSSignalWord = Danger , HPhrases = {{H-phrases, 200, 301, 311, 331 , PPhrases = {{P-phrases, 201, 202, 261, 264, 270, 271, 280, 281, 301+310, 302+352, 304+340, 311, 312, 321, 322, 330, 361, 363, 372, 373, 380, 401, 403+233, 405, 501 Potassium picrate, or potassium 2,4,6-trinitrophenolate, is an organic chemical, a

picrate A picrate is a salt containing the anion (O2N)3C6H2O− or an ester derivative of the picrate anion. These salts are often produced by reactions of picric acid (2,4,6-trinitrophenol). The picrate ion is intensely yellow, although many of its salt ...

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...

. It is a reddish yellow or green crystalline material. It is a

primary explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

. Anhydrous potassium picrate forms

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

crystals.

History

Potassium picrate was first prepared as impure in mid-17th century by

Johann Rudolf Glauber Johann Rudolf Glauber (10 March 1604 – 16 March 1670) was a German-Dutch alchemy, alchemist and chemist. Some historians of science have described him as one of the first chemical engineers. His discovery of sodium sulfate in 1625 led to t ...

by dissolving

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin th ...

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

and neutralizing with

potassium carbonate Potassium carbonate is the inorganic compound with the formula K2 CO3. It is a white salt, which is soluble in water. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used in the production of soap and gl ...

. It is commonly made by neutralizing

picric acid Picric acid is an organic compound with the formula (O2N)3C6H2OH. Its IUPAC name is 2,4,6-trinitrophenol (TNP). The name "picric" comes from el, πικρός (''pikros''), meaning "bitter", due to its bitter taste. It is one of the most acidic ...

by potassium carbonate. It was used since 1869. Its chief applications are in

pyrotechnics Pyrotechnics is the science and craft of creating such things as fireworks, safety matches, oxygen candles, explosive bolts and other fasteners, parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demolition. ...

, in some

whistle mix A pyrotechnic composition is a substance or mixture of substances designed to produce an effect by heat, light, sound, gas/smoke or a combination of these, as a result of non-detonative self-sustaining exothermic chemical reactions. Pyrotechnic s ...

es, as a component of

explosive An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An expl ...

s (with

potassium nitrate Potassium nitrate is a chemical compound with the chemical formula . This alkali metal nitrate salt is also known as Indian saltpetre (large deposits of which were historically mined in India). It is an ionic salt of potassium ions K+ and nitrat ...

and

charcoal Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, cal ...

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the e ...

s (with

potassium chlorate Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It ...

), and

explosive primer A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common. The commercial use of explosives uses electr ...

s (with

lead picrate Lead picrate is an organic picrate salt. It is a sensitive and highly explosive compound that is typically found as a hydrate. Dry lead picrate is incredibly dangerous and cannot be handled without explosive decomposition occurring. History ...

and

Description

Potassium picrate is not a very powerful explosive. It is somewhat shock-sensitive. In contact with flame it

deflagrates Deflagration (Lat: ''de + flagrare'', "to burn down") is subsonic combustion in which a pre-mixed flame propagates through a mixture of fuel and oxidizer. Deflagrations can only occur in pre-mixed fuels. Most fires found in daily life are diffu ...

with a loud sound. If ignited in confined space, it will

detonate Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

. It is more sensitive than

. In contact with metals (e.g. lead, calcium, iron), potassium picrate, like

ammonium picrate Dunnite, also known as Explosive D or systematically as ammonium picrate, is an explosive developed in 1906 by US Army Major Beverly W. Dunn, who later served as the chief inspector of the Bureau of Transportation Explosives. Ammonium picrate is ...

and

, 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

surfactant Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...

s in water; materials detectable by this method are called potassium picrate active substances (PPAS).

Synthesis

As with other picrates, potassium picrate may be produced by the neutralization of picric acid with the corresponding carbonate. As picric acid is barely soluble in water the reaction must be done in an appropriate solvent like methanol. First dissolving the picric acid in methanol and then adding potassium carbonate will result in potassium picrate. Temperature control is important to prevent detonation or excessive methanol evaporation.

Sensitivity

According to Urbanski, Potassium picrate detonated 10% of the time when struck by a mass of 2kg dropped from the height of 21cm. By comparison, the more sensitive anhydrous lead picrate detonated 10% of the time when struck by the same mass dropped from the height of 2cm.

References

# # Urbanski, Tadeusz (1964), Chemistry and Technology of Explosives, Volume 1, New York: Pergamon Press. Picrates Potassium compounds Explosive chemicals

History

Description

Synthesis

Sensitivity

See also

References