- Carbonate of potash redirects here. For one of potassium carbonate's impure forms, see potash.
Potassium carbonate is a white salt, soluble in water (insoluble in alcohol), which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid. Potassium carbonate is used in the production of soap and glass.
Potassium carbonate was first identified in 1742 by Antonio Campanella and is the primary component of potash
and the more refined pearlash
or salts of tartar
. Historically pearlash was created by baking potash
in a kiln
to remove impurities. The fine white powder remaining was the pearlash. The first patent
issued by the U.S. Patent Office
was awarded to Samuel Hopkins
in 1790 for an improved method of making potash and pearlash.
In late 18th century North America, before the development of baking powder, pearl ash was used as a leavening agent in "quick breads".
Other terms for potassium carbonate:
- Carbonate of potash
- Dipotassium carbonate
- Dipotassium salt
- Pearl ash
- Salt of tartar
- Salt of wormwood
Today potassium carbonate is prepared commercially by the electrolysis
of potassium chloride
. The resulting potassium hydroxide
is then carbonated using carbon dioxide
to form potassium carbonate, which is often used to produce other .
- 2KOH + CO2 → K2CO3 + H2O
Pearl ash has been used for soap
, and china
In the laboratory, it may be used as a mild drying agent where other drying agents such as calcium chloride may be incompatible. However, it is not suitable for acidic compounds.
Mixed with water it causes an exothermic reaction that results in a temperature change, producing heat.
In cuisine, it is used as an ingredient in the production of grass jelly, a food consumed in Chinese and Southeast Asian cuisines.
Potassium carbonate is being used as the electrolyte in many cold fusion experiments.
Potassium carbonate is sometimes used as a buffering agent in the production of mead or wine.
Aqueous potassium carbonate is also used as a fire suppressant in extinguishing deep fat fryers and various other B class related fires.
Potassium carbonate is used in reactions to maintain anhydrous conditions without reacting with the reactants and product formed. It may also be used to pre-dry some ketones, alcohols, and amines prior to distillation.
A Dictionary of Science
, Oxford University Press Inc.
, New York