Potassium persulphate is the inorganic compound that is a white crystalline powder solid. This substance is known as potassium peroxydisulphate or KPS. It is barely soluble in water, but it manages to dissolve more at warmer temperatures. This compound is a strong oxidant, that is usually used as a free-radical initiator for polymerization.
Potassium persulfate can be prepared by electrolysis of a cold solution potassium bisulphate in sulfuric acid at a high current density
2 KHSO4 → K2S2O8 + H2
It can also be prepared by adding potassium bisulphate (KHSO4) to a solution of the more soluble salt ammonium peroxydisulphate (NH4)2S2O8. In principle, it can be prepared by chemical oxidation of potassium sulfate using fluorine.
The Main Uses of Potassium Persulphate are:
- KSP is used to initiate polymerization of various alkenes leading to commercially important polymers such as styrene-butadiene rubber and polytetrafluoroethylene.
- It is used in organic chemistry as an oxidizing agent; for instance in the Elbs persulfate oxidation of phenols and the Boyland–Sims oxidation of anilines.
- It serves as a bleaching and lightening agent.
- It has been used as an improving agent for flour with E922.