Potassium acetate (also called potassium ethanoate), (CH3COOK) is the potassium salt of acetic acid. It is a hygroscopic solid at room temperature.

Potassium acetate
Skeletal formula of potassium acetate
Preferred IUPAC name
Potassium acetate
Other names
Potassium ethanoate, E261
3D model (JSmol)
ECHA InfoCard 100.004.385 Edit this at Wikidata
E number E261 (preservatives)
  • InChI=1S/C2H4O2.K/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1 ☒N
  • InChI=1/C2H4O2.K/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1
  • CC(=O)[O-].[K+]
Molar mass 98.142 g·mol−1
Appearance White deliquescent crystalline powder
Density 1.8 g/cm3 (20 °C)[1]
1.57 g/cm3 (25 °C)
Melting point 292 °C (558 °F; 565 K)
Boiling point Decomposes
216.7 g/100 mL (0.1 °C)
233.8 g/100 mL (10 °C)
268.6 g/100 mL (25 °C)
320.8 g/100 mL (40 °C)
390.7 g/100 mL (96 °C)[2]
Solubility Soluble in alcohol, liquid ammonia
Insoluble in ether, acetone
Solubility in methanol 24.24 g/100 g (15 °C)
53.54 g/100 g (73.4 °C)[1]
Solubility in ethanol 16.3 g/100 g[1]
Solubility in sulfur dioxide 0.06 g/kg (0 °C)[1]
Acidity (pKa) 4.76
109.38 J/mol·K[3]
150.82 J/mol·K[3]
−722.6 kJ/mol[1]
B05XA17 (WHO)
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Lethal dose or concentration (LD, LC):
3250 mg/kg (oral, rat)[4]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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It can be prepared by treating a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic acid:


This sort of reaction is known as an acid-base neutralization reaction.

The sesquihydrate in water solution (CH3COOK·1½H2O) begins to form semihydrate at 41.3 °C.[2]





Potassium acetate (as a substitute for calcium chloride or magnesium chloride) can be used as a deicer to remove ice or prevent its formation. It offers the advantage of being less aggressive on soils and much less corrosive:[5] for this reason, it is preferred for airport runways although it is more expensive.[6]

Fire extinguishing


Potassium acetate is the extinguishing agent used in Class K fire extinguishers because of its ability to cool and form a crust over burning oils.

Food additive


Potassium acetate is used in processed foods as a preservative and acidity regulator. In the European Union, it is labeled by the E number E261;[7] it is also approved for usage in the USA,[8] Australia, and New Zealand.[9] Potassium hydrogen diacetate (CAS #4251-29-0 ) with formula KH(OOCCH3)2 is a related food additive with the same E number as potassium acetate.

Medicine and biochemistry


In medicine, potassium acetate is used as part of electrolyte replacement protocols in the treatment of diabetic ketoacidosis because of its ability to break down to bicarbonate to help neutralize the acidotic state.

In molecular biology, potassium acetate is used to precipitate dodecyl sulfate (DS) and DS-bound proteins to extract ethanol from DNA.

Potassium acetate is used in mixtures applied for tissue preservation, fixation, and mummification. Most museums today use a formaldehyde-based method recommended by Kaiserling in 1897 which contains potassium acetate.[10] This process was used to soak Lenin's corpse.[11]

Use in executions


Potassium acetate was incorrectly used in place of potassium chloride when putting a prisoner to death in Oklahoma in January 2015.[12] Charles Frederick Warner was executed on January 15, 2015 with potassium acetate; this was not public knowledge until the scheduled execution of Richard Glossip was called off. [13] In August 2017, the U.S. state of Florida executed Mark James Asay using a combination of etomidate, rocuronium bromide, and potassium acetate.[14] The drug was also used in the February 2023 execution of Donald Dillbeck, once again in combination with etomidate and rocuronium bromide. [15]



Potassium acetate is used as a catalyst in the production of polyurethanes.[16]



It is used as a diuretic and urinary alkalizer. Before modern chemistry, it was variously called terra foliata tartari, sal Sennerti, tartarus regeneratus, arcanum tartari and sal diureticus.[17] In 1760 it was used in the preparation of Cadet's fuming liquid ((CH3)2As)2O, the first organometallic compound ever produced.


  1. ^ a b c d e "Potassium acetate".
  2. ^ a b Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand.
  3. ^ a b Acetic acid, potassium salt in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) (retrieved 2014-05-18)
  4. ^ https://chem.nlm.nih.gov/chemidplus/rn/127-08-2 [dead link]
  5. ^ Gruber, Michael R.; Hofko, Bernhard; Hoffmann, Markus; Stinglmayr, David; Seifried, Teresa M.; Grothe, Hinrich (April 2023). "Deicing performance of common deicing agents for winter maintenance with and without corrosion-inhibiting substances". Cold Regions Science and Technology. 208: 103795. doi:10.1016/j.coldregions.2023.103795.
  6. ^ Harrington-Hughes, Kathryn (1992). Handbook of test methods for evaluating chemical deicers. Transportation Research Board. ISBN 9789994805839.
  7. ^ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
  8. ^ US Food and Drug Administration: "Listing of Food Additives Status Part II". Food and Drug Administration. Retrieved 2011-10-27.
  9. ^ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27.
  10. ^ Dale Ulmer (1994). "Fixation. The Key to Good Tissue Preservation" (PDF). Journal of the International Society for Plastination. 8 (1): 7–10. Archived from the original (PDF) on 2011-05-16. Retrieved 2017-09-08.
  11. ^ Andrew Nagorski (2007). The Greatest Battle. Simon and Schuster. p. 53.
  12. ^ "Oklahoma used wrong drug in Charles Warner's execution, autopsy report says".
  13. ^ Eyder Peralta. "Oklahoma Used The Wrong Drug To Execute Charles Warner". NPR.
  14. ^ Jason Dearon. "Florida executes convicted killer Mark Asay using new drug". Sun Sentinel.
  15. ^ Kathryn Varn. "Convicted murderer Donald Dillbeck has been executed. Here's the latest". Tallahassee Democrat.
  16. ^ Hosea Cheung, Robin S. Tanke, G. Paul Torrence "Acetic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH, Weinheim. doi:10.1002/14356007.a01_045.
  17. ^ Crosland, Maurice P. (2004-01-01). Historical Studies in the Language of Chemistry. Courier Corporation. ISBN 978-0-486-43802-3.