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.
History
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:
Production
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
Applications
Pearl ash has been used for
soap,
glass, and
china production.
Pearlash added to hard water will soften the water.
In the laboratory, it may be used as a mild
drying agent where other drying agents such as
calcium chloride and
magnesium sulfate may be incompatible. However, it is not suitable for acidic compounds, but can be useful for drying an organic phase if one has a small amount of acidic impurity.
Mixed with water it causes an
exothermic reaction.
It is mixed with distilled water to make a safer electrolyte for oxyhydrogen production than potassium hydroxide, the more commonly used electrolyte.
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.
