Potassium acetate
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| Names | |
|---|---|
| Other names
Potassium salt; E261
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| Identifiers | |
| ChEMBL | |
| ECHA InfoCard | 100.004.385 |
| E number | E261 (preservatives) |
CompTox Dashboard (EPA)
|
|
| Properties | |
| CH3CO2K | |
| Molar mass | 98.15 g/mol |
| Appearance | White deliquescent crystalline powder |
| Density | 1.57 g/cm3 |
| Melting point | 292 °C (558 °F; 565 K) |
| 253 g/100 mL (20 °C) 492 g/100 mL (62 °C) | |
| Solubility | soluble in methanol, ethanol, liquid ammonia insoluble in ether, acetone |
| Acidity (pKa) | 4.76 |
| Hazards | |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium acetate (CH3CO2K) is the potassium salt of acetic acid.
Preparation
It can be prepared by reacting 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. Potassium acetate is the salt that forms along with water as acetic acid and potassium hydroxide are neutralized together.
Conditions/substances to avoid are: moisture, heat, flames, ignition sources, and strong oxidizing agents.
Applications
Potassium acetate can be used as a deicer instead of chloride salts such as calcium chloride or magnesium chloride. It offers the advantage of being less aggressive on soils and much less corrosive, and for this reason is preferred for airport runways. It is, however, more expensive. Potassium acetate is also the extinguishing agent used in class K fire extinguishers because of its ability to cool and form a crust over burning oils.
In medicine, potassium acetate is used as part of replacement protocols in the treatment of diabetic ketoacidosis because of its ability to break down into bicarbonate and help neutralize the acidotic state.
Potassium acetate is used as a food additive as a preservative and acidity regulator. In the European Union, it is labeled by the E number E261.
In molecular biology, potassium acetate is used to precipitate dodecyl sulfate (DS) and DS-bound proteins, allowing the removal of proteins from DNA. It is also used as a salt for the ethanol precipitation of DNA.
Potassium acetate is used in mixtures applied for tissue preservation, fixation, and mummification. Most museums today use the formaldehyde-based method recommended by Kaiserling in 1897 which contains potassium acetate.[1] For example, Lenin's mummy was soaked in a bath containing potassium acetate.[2]
Potassium acetate was originally used in the preparation of Cadet's fuming liquid, the first organometallic compound produced. It is used as diuretic and urinary alkaliser, and acts by changing the physical properties of the body fluids and by functioning as an alkali after absortion.
References
- ^ Dale Ulmer, "Fixation. The Key to Good Tissue Preservation.", Journal of the International Society for Plastination, Vol 8 (1): 7-10, 1994
- ^ Andrew Nagorski, "The Greatest Battle", Simon and Shuster, 2007, page 53.