Potassium perchlorate

Overview
Potassium perchlorate, a perchlorate salt with the chemical formula KClO4, is a strong oxidizer. It is a colorless, crystalline substance that melts at about 610 °C. It is one of the most common oxidizers used in fireworks, ammunition percussion caps, explosive primers, and is used variously in propellants, flash compositions, stars, and sparklers. It has been used as a solid rocket propellant, though in that application it has mostly been replaced by the higher performance ammonium perchlorate. KClO4 has the lowest solubility of all perchlorates (1.5 g in 100 g of water at 25 °C).

Reactions
As an oxidizer, KClO4 reacts with a wide variety of fuels. A common example is glucose, C6H12O6.


 * 3 KClO4 + C6H12O6 → 6 H2O + 6 CO2 + 3 KCl

When mixed with cane sugar, it can be used as a low explosive, if the necessary confinement is provided. Otherwise the mixture will simply deflagrate with an intense purple flame indicative of potassium salts. Flash compositions used in firecrackers usually consist of fine aluminium powder mixed with potassium perchlorate.

Potassium perchlorate can be used safely in the presence of sulfur; however, potassium chlorate cannot. The common explanation for this is that the sulfur will, given time, produce minute quantities of sulfurous acid and sulfuric acid. These will, in turn, react with potassium chlorate to produce chloric acid, which is highly unstable and can lead to premature ignition of the composition. The corresponding acid of potassium perchlorate, perchloric acid, is stable enough as to prevent spontaneous ignition.

Production
Potassium perchlorate is produced by double decomposition reaction with sodium perchlorate and potassium chloride. Sodium perchlorate is manufactured by anodic oxidation of sodium chloride.

In medicine
Potassium perchlorate can be used as a potent antithyroid agent used to treat hyperthyroidism, usually in combination with one other medication.