Potassium acetate
| Potassium acetate | ||
|---|---|---|
 | ||
| Other names Potassium salt; E261 | ||
| Identifiers | ||
| CAS number | 127-08-2  | |
| PubChem | 517044 | |
| ChEMBL | CHEMBL1201058  | |
| ATC code | B05 | |
| Jmol-3D images | {{#if:CC(=O)[O-].[K+]|Image 1 | |
| ||
| Properties | ||
| Molecular formula | 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 | |
| Solubility in water | 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 | ||
| EU classification | not listed | |
| NFPA 704 |
 1
1
1
| |
| LD50 | 3250 mg/kg (oral, rat) | |
| (verify) (what is: /?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| Infobox references | ||
Potassium acetate (CH3CO2K) is the potassium salt of acetic acid.
Preparation
It can be prepared by treating a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic acid:
- CH3COOH + KOH → CH3CO2K + H2O
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 is used as a catalyst in the production of polyurethanes.[1]
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.
Food additive
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;[2] it is also approved for usage in the USA[3] and Australia and New Zealand.[4] Potassium diacetate (CAS#4251-29-0) with formula KH(O2CCH3)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 replacement protocols in the treatment of diabetic ketoacidosis because of its ability to break down into bicarbonate and help neutralize the acidotic state.
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.[5] For example, Lenin's mummy was soaked in a bath containing potassium acetate.[6]
Historical
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
- ↑ 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.
- ↑ UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
- ↑ US Food and Drug Administration: "Listing of Food Additives Status Part II". Retrieved 2011-10-27.
- ↑ Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27.
- ↑ 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 Schuster, 2007, page 53.