Potassium carbonate#Production
{{Short description|Chemical compound}}
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 476994545
| Name =
| ImageFile = Potassium carbonate.svg
| ImageFile1 = Potassium-carbonate-xtal-3D-SF.png
| ImageFile2 = Potassium carbonate.jpg
| ImageSize =
| IUPACName = Potassium carbonate
| OtherNames = Carbonate of potash, dipotassium carbonate, sub-carbonate of potash, pearl ash, pearlash, potash, salt of tartar, salt of wormwood.
| SystematicName =
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 10949
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 131526
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = BQN1B9B9HA
| UNII1_Ref = {{fdacite|correct|FDA}}
| UNII1 = L9300DKS8U
| UNII1_Comment = (sesquihydrate)
| InChI = 1/CH2O3.2K/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2
| InChIKey = BWHMMNNQKKPAPP-NUQVWONBAS
| SMILES = C(=O)([O-])[O-].[K+].[K+]
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/CH2O3.2K/c2-1(3)4;;/h(H2,2,3,4);;/q;2*+1/p-2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = BWHMMNNQKKPAPP-UHFFFAOYSA-L
| CASNo = 584-08-7
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo1_Ref = {{cascite|correct|CAS}}
| CASNo1 = 6381-79-9
| CASNo1_Comment = sesquihydrate
| PubChem = 11430
| RTECS = TS7750000
}}
| Section2 = {{Chembox Properties
| Formula = {{Chem2|K2CO3}}
| K=2|C=1|O=3
| Appearance = White, hygroscopic solid
| Density = 2.43{{nbsp}}g/cm3
| MeltingPtC = 891
| BoilingPt = Decomposes
| Solubility = 110.3{{nbsp}}g/(100{{nnbsp}}mL) (20{{nbsp}}°C)
149.2{{nbsp}}g/(100{{nnbsp}}mL) (100{{nbsp}}°C)
| SolubleOther = {{ubl|3.11{{nbsp}}g/(100{{nnbsp}}mL) (25{{nbsp}}°C) methanol|Insoluble in alcohol, acetone}}
| pKa = 10.25
| MagSus = −59.0·10−6{{nbsp}}cm3/mol
}}
| Section3 =
| Section4 = {{Chembox Thermochemistry
| HeatCapacity = 114.4 J/(mol·K)
| Entropy = 155.5 J/(mol·K)
| DeltaHform = −1151.0 kJ/mol
| DeltaGfree = −1063.5 kJ/mol
| DeltaHcombust =
| DeltaHfus = 27.6 kJ/mol
| DeltaHvap =
| DeltaHsublim =
| HHV =
| LHV =
}}
| Section5 =
| Section6 =
| Section7 = {{Chembox Hazards
| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics1588.htm ICSC 1588]
| GHSPictograms = {{GHS07}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302|315|319|335}}
| PPhrases = {{P-phrases|261|305+351+338}}
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S =
| FlashPt = Non-flammable
}}
| Section8 = {{Chembox Related
| OtherAnions = {{ubl|Potassium bicarbonate|Potassium sulfate|Potassium chromate}}
| OtherCations = {{ubl|Lithium carbonate|Sodium carbonate|Rubidium carbonate|Caesium carbonate}}
| OtherCompounds = {{ubl|Ammonium carbonate|Calcium carbonate}}
}}
}}
Potassium carbonate is the inorganic compound with the formula {{Chem2|K2CO3|auto=1}}. It is a white salt, which is soluble in water and forms a strongly alkaline solution. It is deliquescent, often appearing as a damp or wet solid. Potassium carbonate is mainly used in the production of soap and glass.{{cite encyclopedia|author=H. Schultz |author2=G. Bauer |author3=E. Schachl |author4=F. Hagedorn |author5=P. Schmittinger |title=Potassium Compounds|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2005|publisher=Wiley-VCH|location=Weinheim|doi=10.1002/14356007.a22_039|isbn=3-527-30673-0}} Commonly, it can be found as the result of leakage of alkaline batteries.{{Cite web |last=List |first=Jenny |date=October 19, 2022 |title=Crusty Leaking Cells Kill Your Tech. Just What's Going On? |url=https://hackaday.com/2022/10/19/crusty-leaking-cells-kill-your-tech-just-whats-going-on/ |archive-url=https://web.archive.org/web/20230530235234/https://hackaday.com/2022/10/19/crusty-leaking-cells-kill-your-tech-just-whats-going-on/ |archive-date=May 30, 2023 |website=Hackaday}} Potassium carbonate is a potassium salt of carbonic acid. This salt consists of potassium cations {{chem2|K+}} and carbonate anions {{chem2|CO3(2−)}}, and is therefore an alkali metal carbonate.
History
{{About|2=a longer section on a related group of chemicals with much common history|3=Potash#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.{{Cite web |title=Milestones in U.S. patenting |url=https://www.uspto.gov/patents/milestones |access-date=2023-08-04 |website=www.uspto.gov |language=en-US |archive-date=2023-03-22 |archive-url=https://web.archive.org/web/20230322074743/https://www.uspto.gov/patents/milestones |url-status=live }}
In late 18th-century North America, before the development of baking powder, pearl ash was used as a leavening agent for quick breads.See references to "pearl ash" in "American Cookery" by Amelia Simmons, printed by Hudson & Goodwin, Hartford, 1796.{{cite book |last1=Civitello |first1=Linda |title=Baking powder wars: the cutthroat food fight that revolutionized cooking |date=2017 |publisher=University of Illinois Press |location=Urbana, Illinois |isbn=978-0-252-04108-2 |pages=18–22}}
Production
The modern commercial production of potassium carbonate is by reaction of potassium hydroxide with carbon dioxide:
:{{chem2|2 KOH + CO2 → K2CO3 + H2O}}
From the solution crystallizes the sesquihydrate {{chem2|K2CO3*1.5H2O}} ("potash hydrate"). Heating this solid above {{Convert|200|°C|°F|abbr=on}} 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:
:{{chem2|2 KHCO3 → K2CO3 + H2O + CO2}}
Applications
- (historically) for soap, glass, and dishware production;{{cn|date=December 2024}}
- as a dietary potassium supplement, containing 56% of elemental potassium,{{cite journal|doi=10.1088/1755-1315/648/1/012185 |title=Applications of guano and K2CO3 on soil potential-P, potential-K on Andisols |date=2021 |last1=Zakiah |first1=K. |last2=Maulana |first2=M. R. |last3=Widowati |first3=L. R. |last4=Mutakin |first4=J. |journal=IOP Conference Series: Earth and Environmental Science |volume=648 |page=012185 |doi-access=free }} 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;{{cite web | url=https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/ | title=Office of Dietary Supplements - Potassium | access-date=2024-12-18 | archive-date=2022-08-11 | archive-url=https://web.archive.org/web/20220811045719/https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/ | url-status=live }}{{cite web | url=https://www.drugs.com/inactive/potassium-carbonate-106.html | title=Potassium Carbonate: What is it and where is it used? | access-date=2024-12-18 | archive-date=2024-07-17 | archive-url=https://web.archive.org/web/20240717072535/https://www.drugs.com/inactive/potassium-carbonate-106.html | url-status=live }}
- 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.Leonard, J.; Lygo, B.; Procter, G. "Advanced Practical Organic Chemistry" 1998, Stanley Thomas Publishers Ltd
- 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, although in combination with hartshorn;{{cn|date=December 2024}}
- 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 aroma{{emdash}}the 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;{{cn|date=December 2024}}
- as a buffering agent in the production of mead or wine;{{cn|date=December 2024}}
- in antique documents, it is reported to have been used to soften hard water;{{cite book|author=Lydia M. Child|title=The American Frugal Housewife|year=1832}}
- as a fire suppressant in extinguishing deep-fat fryers and various other oil/fat/grease related fires;{{cn|date=June 2025}}{{cn|date=June 2025|reason=author didn't seem to know that oil/fat/grease fires are not Class B, see the fire-class article}}
- in condensed aerosol fire suppression, although as the byproduct of potassium nitrate;{{cn|date=December 2024}}
- as an ingredient in welding fluxes, and in the flux coating on arc-welding rods;{{cn|date=December 2024}}
- as an animal feed ingredient to satisfy the potassium requirements of farmed animals such as broiler breeder chickens;{{cn|date=December 2024}}
- as an acidity regulator in Swedish snus snuff tobacco.{{cn|date=December 2024}}
References
{{Reflist}}
Bibliography
- A Dictionary of Science, Oxford University Press, New York, 2004
- {{cite journal|url=https://www.researchgate.net/publication/231535294|title=Solubility of Potassium Carbonate and Potassium Hydrocarbonate in Methanol|first1=Andrew|last1=Yu. Platonov|first2=Andrey|last2=Evdokimov|first3=Alexander|last3=Kurzin|first4=Helen|last4=D. Maiyorova|date=29 June 2002|journal=Journal of Chemical & Engineering Data|volume=47|issue=5|pages=1175–1176|doi=10.1021/je020012v}}
External links
- [http://www.inchem.org/documents/icsc/icsc/eics1588.htm International Chemical Safety Card 1588]
{{Potassium compounds}}
{{Carbonates}}
{{Authority control}}
Category:Deliquescent materials