Potassium carbonate

History

Potassium carbonate is the primary component of potash and the more refined pearl ash or salt 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 for quick breads.

Production

The modern commercial production of potassium carbonate is by reaction of potassium hydroxide with carbon dioxide: : From the solution crystallizes the sesquihydrate ("potash hydrate"). Heating this solid above 200 °C gives the anhydrous salt. In an alternative method, potassium chloride is treated with carbon dioxide in the presence of an organic amine to give potassium bicarbonate, which is then calcined: :

Applications

• (historically) for soap, glass, and dishware production;
• as a dietary potassium supplement, containing 56% of elemental potassium, in tablet or powder form to address low blood potassium levels caused by inadequate nourishment, nausea and vomiting, diarrhea, or potassium-depleting medications such as corticosteroids or diuretics;
• 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.
• in cuisine, where it has many traditional uses. It is used in some types of Chinese noodles and mooncakes, as well as Asian grass jelly and Japanese ramen. German gingerbread recipes often use potassium carbonate as a baking agent.
• in the alkalization of cocoa powder to produce Dutch process chocolate by balancing the pH (i.e., reduce the acidity) of natural cocoa beans; it also enhances aromathe process of adding potassium carbonate to cocoa powder is usually called "Dutching" (and the products referred to as Dutch-processed cocoa powder), as the process was first developed in 1828 by Dutchman Coenraad Johannes van Houten;
• as a buffering agent in the production of mead or wine;
• in antique documents, it is reported to have been used to soften hard water;
• as a fire suppressant in extinguishing deep-fat fryers and various other oil/fat/grease related fires;
• in condensed aerosol fire suppression, although as the byproduct of potassium nitrate;
• as an ingredient in welding fluxes, and in the flux coating on arc-welding rods;
• as an animal feed ingredient to satisfy the potassium requirements of farmed animals such as broiler breeder chickens;
• as an acidity regulator in Swedish snus snuff tobacco.

References

Bibliography

• A Dictionary of Science, Oxford University Press, New York, 2004

References

1. (2016). "CRC handbook of chemistry and physics: a ready-reference book of chemical and physical data.".
2. Chambers, Michael. "ChemIDplus - 584-08-7 - BWHMMNNQKKPAPP-UHFFFAOYSA-L - Potassium carbonate [USP] - Similar structures search, synonyms, formulas, resource links, and other chemical information.".
3. (14 March 2022). "The Difference Between Natural and Alkalized Cacao Powder and its Uses".
4. H. Schultz. (2005). "Potassium Compounds". Wiley-VCH.
5. List, Jenny. (October 19, 2022). "Crusty Leaking Cells Kill Your Tech. Just What's Going On?".
6. "Milestones in U.S. patenting".
7. See references to "pearl ash" in "American Cookery" by Amelia Simmons, printed by Hudson & Goodwin, Hartford, 1796.
8. (2017). "Baking powder wars: the cutthroat food fight that revolutionized cooking". University of Illinois Press.
9. (2021). "Applications of guano and K₂CO₃ on soil potential-P, potential-K on Andisols". IOP Conference Series: Earth and Environmental Science.
10. "Office of Dietary Supplements - Potassium".
11. "Potassium Carbonate: What is it and where is it used?".
12. Leonard, J.; Lygo, B.; Procter, G. "Advanced Practical Organic Chemistry" 1998, Stanley Thomas Publishers Ltd
13. Dunk, Anja. (2021). "Advent". Quadrille.
14. Lydia M. Child. (1832). "The American Frugal Housewife".