Potassium perchlorate
Encyclopedia
Potassium perchlorate is the inorganic salt with the chemical formula K
Cl
O4
. Like other perchlorate
s, this salt is a strong oxidizer
and potentially reacts with many organic substances. This usually obtained as a colorless, crystalline solid is a common oxidizer used in fireworks
, ammunition
percussion cap
s, explosive primers, and is used variously in propellant
s, flash compositions
, stars, and sparklers. It has been used as a solid rocket
propellant, although in that application it has mostly been replaced by the higher performance ammonium perchlorate
. KClO4 has the lowest solubility
of the alkali metal
perchlorates (1.5 g in 100 mL of water at 25 °C).
with KCl. This single precipitation reaction exploits the low solubility of KClO4, which is about 100 times less than the solubility of NaClO4 (209.6 g/100 mL at 25 °C).
to combustible materials, greatly increasing their rate of combustion relative to that in air. Thus, with glucose
it gives carbon dioxide:
The conversion of solid glucose into hot gaseous CO2 is the basis of the explosive force of this and other such mixtures. Even with cane sugar, KClO4 yields a low explosive, provided the necessary confinement. Otherwise such mixtures simply deflagrate with an intense purple flame characteristic of potassium
. Flash compositions used in firecracker
s usually consist of fine aluminium
powder mixed with potassium perchlorate.
As an oxidizer, potassium perchlorate can be used safely in the presence of sulfur
, whereas potassium chlorate
cannot. The greater reactivity of chlorate is typical – perchlorates are kinetically poorer oxidants. Chlorate produces chloric acid
, which is highly unstable and can lead to premature ignition of the composition. Correspondingly, perchloric acid
is quite stable.
, usually in combination with one other medication. This application exploits the similar ionic radii and hydrophilicity of perchlorate and iodide
.
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...
Cl
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
O4
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...
. Like other perchlorate
Perchlorate
Perchlorates are the salts derived from perchloric acid . They occur both naturally and through manufacturing. They have been used as a medicine for more than 50 years to treat thyroid gland disorders. They are used extensively within the pyrotechnics industry, and ammonium perchlorate is also a...
s, this salt is a strong oxidizer
Oxidizing agent
An oxidizing agent can be defined as a substance that removes electrons from another reactant in a redox chemical reaction...
and potentially reacts with many organic substances. This usually obtained as a colorless, crystalline solid is a common oxidizer used in fireworks
Fireworks
Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...
, ammunition
Ammunition
Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...
percussion cap
Percussion cap
The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
s, explosive primers, and is used variously in propellant
Propellant
A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...
s, flash compositions
Flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and if confined produces a loud report. It is widely used in theatrical pyrotechnics and fireworks and was once used for flashes in photography.Different varieties of flash powder are made from...
, stars, and sparklers. It has been used as a solid rocket
Solid rocket
A solid rocket or a solid-fuel rocket is a rocket engine that uses solid propellants . The earliest rockets were solid-fuel rockets powered by gunpowder; they were used by the Chinese in warfare as early as the 13th century and later by the Mongols, Arabs, and Indians.All rockets used some form of...
propellant, although in that application it has mostly been replaced by the higher performance ammonium perchlorate
Ammonium perchlorate
Ammonium perchlorate is an inorganic compound with the formula NH4ClO4. It is the salt of perchloric acid and ammonia. It is a powerful oxidizer, which is why its main use is in solid propellants...
. KClO4 has the lowest solubility
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
of the alkali metal
Alkali metal
The alkali metals are a series of chemical elements in the periodic table. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, along with hydrogen. The alkali metals are lithium , sodium , potassium , rubidium , caesium , and francium...
perchlorates (1.5 g in 100 mL of water at 25 °C).
Production
KClO4 is prepared industrially by treating an aqueous solution of sodium perchlorateSodium perchlorate
Sodium perchlorate is the inorganic compound with the chemical formula NaClO4. It is the most soluble of the common perchlorate salts. It is a white crystalline, hygroscopic solid that is highly soluble in water and in alcohol...
with KCl. This single precipitation reaction exploits the low solubility of KClO4, which is about 100 times less than the solubility of NaClO4 (209.6 g/100 mL at 25 °C).
Oxidizing properties
KClO4 is an oxidizer in the sense that it exothermically transfers oxygenOxygen
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...
to combustible materials, greatly increasing their rate of combustion relative to that in air. Thus, with glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...
it gives carbon dioxide:
- 3 KClO4 + C6H12O6 → 6 H2O + 6 CO2 + 3 KCl
The conversion of solid glucose into hot gaseous CO2 is the basis of the explosive force of this and other such mixtures. Even with cane sugar, KClO4 yields a low explosive, provided the necessary confinement. Otherwise such mixtures simply deflagrate with an intense purple flame characteristic of potassium
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...
. Flash compositions used in firecracker
Firecracker
A firecracker is a small explosive device primarily designed to produce a large amount of noise, especially in the form of a loud bang; any visual effect is incidental to this goal. They have fuses, and are wrapped in a heavy paper casing to contain the explosive compound...
s usually consist of fine aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
powder mixed with potassium perchlorate.
As an oxidizer, potassium perchlorate can be used safely in the presence of sulfur
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...
, whereas potassium chlorate
Potassium chlorate
Potassium chlorate is a compound containing potassium, chlorine and oxygen atoms, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. It is the most common chlorate in industrial use...
cannot. The greater reactivity of chlorate is typical – perchlorates are kinetically poorer oxidants. Chlorate produces chloric acid
Chloric acid
Chloric acid, HClO3, is an oxoacid of chlorine, and the formal precursor of chlorate salts. It is a strong acid and oxidizing agent....
, which is highly unstable and can lead to premature ignition of the composition. Correspondingly, perchloric acid
Perchloric acid
Perchloric acid is the inorganic compound with the formula HClO4. Usually encountered as an aqueous solution, this colourless compound is a strong acid comparable in strength to sulfuric and nitric acids. It is a powerful oxidizer, but its aqueous solutions up to appr. 70% are remarkably inert,...
is quite stable.
In medicine
Potassium perchlorate can be used as an antithyroid agent used to treat hyperthyroidismHyperthyroidism
Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
, usually in combination with one other medication. This application exploits the similar ionic radii and hydrophilicity of perchlorate and iodide
Iodide
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. This page is for the iodide ion and its salts. For information on organoiodides, see organohalides. In everyday life, iodide is most commonly encountered as a component of iodized salt,...
.