Not to be confused with potassium peroxymonosulfate

Potassium peroxymonosulfate

Potassium peroxymonosulfate is widely used as an oxidizing agent...

.

Potassium persulfate (K₂

Potassium

Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

S₂

Sulfur

Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

O₈

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

) (also potassium peroxydisulfate or KPS) is a compound.

Uses

It is a food additive

Food additive

Food additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...

 and it is used in organic chemistry

Organic chemistry

Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...

 as an oxidizing agent

Oxidizing agent

An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction...

 for instance in the Elbs persulfate oxidation

Elbs persulfate oxidation

The Elbs persulfate oxidation is the organic reaction of phenols with alkaline potassium persulfate to form para-diphenols.Several reviews have been published.-Reaction mechanism:...

, and in hair dye substances as whitening agent with hydrogen peroxide. It takes also an important role as initiator for emulsion polymerization

Emulsion polymerization

Emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomer, and surfactant. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer are emulsified in a continuous phase of water...

.

For a review of its uses in organic chemistry, see Encyclopedia of Reagents for Organic Synthesis, vol. 1, pp 193-197(1995).

Preparation

Potassium persulfate can be prepared by electrolysis

Electrolysis

In chemistry and manufacturing, electrolysis is a method of using a direct electric current to drive an otherwise non-spontaneous chemical reaction...

 of a mixture between potassium sulfate

Potassium sulfate

Potassium sulfate is a non-flammable white crystalline salt which is soluble in water...

 and hydrogen sulfate at a high current density.

2 KHSO₄ → K₂S₂O₈ + H₂

It can also be prepared by adding potassium bisulfate (KHSO₄) to an electrolyzed solution of ammonium bisulfate

Ammonium bisulfate

Ammonium bisulfate, also known as ammonium hydrogen sulfate, is a white, crystalline solid when it is completely pure, with formula HSO4. It is commonly collected as a byproduct of flue gas desulfurization, formed by partial neutralization of sulfuric acid aerosols by gaseous ammonia, NH3. ...

 (NH₄HSO₄).

Another reaction of its formation is the following (although the practical use of it outside of clandestine chemistry is doubtable).

I₂ + 2KHSO₄ → K₂S₂O₆(O₂) + 2HI

Precautions

Conditions/substances to avoid are: heat

Heat

In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

, flame

Flame

A flame is the visible , gaseous part of a fire. It is caused by a highly exothermic reaction taking place in a thin zone...

s, ignition

Combustion

Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...

 sources, powdered metals, phosphorus

Phosphorus

Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

, hydride

Hydride

In chemistry, a hydride is the anion of hydrogen, H−, or, more commonly, a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, hydrogen is bonded to a more electropositive element or group...

s, organic matter

Organic matter

Organic matter is matter that has come from a once-living organism; is capable of decay, or the product of decay; or is composed of organic compounds...

, halogens, acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s and alkali

Alkali

In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...

s.