Potassium carbonate

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Potassium carbonate
Potassium Carbonate 2D structure.png
Potassium-carbonate-xtal-3D-SF.png
Potassium carbonate.jpg
Identifiers
CAS number 584-08-7 YesY
PubChem 11430
ChemSpider 10949 YesY
UNII BQN1B9B9HA YesY
RTECS number TS7750000
Jmol-3D images Image 1
Properties
Molecular formula K2CO3
Molar mass 138.205 g/mol
Appearance white, hygroscopic solid
Density 2.43 g/cm3
Melting point 891 °C (1,636 °F; 1,164 K)
Boiling point decomposes
Solubility in water 112 g/100 mL (20 °C)
156 g/100 mL (100 °C)
Solubility insoluble in alcohol, acetone
Hazards
MSDS ICSC 1588
EU Index Not listed
R-phrases R22 R36 R37 R38
Main hazards Irritant
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
LD50 1870 mg/kg
Related compounds
Other anions Potassium bicarbonate
Other cations Lithium carbonate
Sodium carbonate
Rubidium carbonate
Caesium carbonate
Related compounds Ammonium carbonate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Potassium carbonate (K2CO3) is a white salt, soluble in water (insoluble in ethanol[1]), 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[edit]

Potassium carbonate was first identified in 1742 by Antonio Campanella and is the primary component of potash and the more refined pearl ash or salts of tartar. Historically, pearl ash was created by baking potash in a kiln to remove impurities. The fine, white powder remaining was the pearl ash. The first patent issued by the US Patent Office was awarded to Samuel Hopkins in 1790 for an improved method of making potash and pearl ash.

In late 18th century North America, before the development of baking powder, pearl ash was used as a leavening agent in quick breads.[2]

Other terms for potassium carbonate:

  • Carbonate of potash
  • Dipotassium carbonate
  • Dipotassium salt
  • Pearl ash
  • Potash
  • Salt of tartar
  • Salt of wormwood

Production[edit]

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 potassium compounds.

2KOH + CO2 → K2CO3 + H2O

Applications[edit]

  • (historically) for soap, glass, and china production
  • as a mild drying agent where other drying agents, such as calcium chloride and magnesium sulfate, may be incompatible. 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. It may also be used to dry some ketones, alcohols, and amines prior to distillation.[3]
  • 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. It is used to tenderize tripe. German gingerbread recipes often use potassium carbonate as a baking agent.
  • as a buffering agent in the production of mead or wine.
  • softening hard water.[4]
  • as a fire suppressant in extinguishing deep-fat fryers and various other B class-related fires
  • in condensed aerosol fire suppression, although as the byproduct of potassium nitrate.
  • an ingredient in welding fluxes, and in the flux coating on arc-welding rods.
  • it is also used in gunpowder as a stable source of energy.
  • stability in neurons to help maintain equilibrium.
  • as an animal feed ingredient to satisfy the potassium requirements of farmed animals such as broiler breeders

References[edit]

  1. ^ http://www.researchgate.net/publication/231535294_Solubility_of_Potassium_Carbonate_and_Potassium_Hydrocarbonate_in_Methanol
  2. ^ See references to "pearl ash" in "American Cookery" by Amelia Simmons, printed by Hudson & Goodwin, Hartford, 1796.
  3. ^ Leonard, J.; Lygo, B.; Procter, G. "Advanced Practical Organic Chemistry" 1998, Stanley Thomas Publishers Ltd
  4. ^ Child, Lydia M. "The American Frugal Housewife" 1832

Bibliography[edit]

A Dictionary of Science, Oxford University Press, New York, 2003

External links[edit]