Potassium acetate

Colourless soluble salt of acetic acid From Wikipedia, the free encyclopedia

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

Quick facts Names, Identifiers ...
Potassium acetate
Skeletal formula of potassium acetate
Skeletal formula of potassium acetate
Names
Preferred IUPAC name
Potassium acetate
Other names
Potassium ethanoate
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.004.385 Edit this at Wikidata
E number E261 (preservatives)
UNII
  • InChI=1S/C2H4O2.K/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1 ☒N
    Key: SCVFZCLFOSHCOH-UHFFFAOYSA-M ☒N
  • InChI=1/C2H4O2.K/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1
    Key: SCVFZCLFOSHCOH-REWHXWOFAA
  • CC(=O)[O-].[K+]
Properties
CH3COOK
Molar mass 98.142 g·mol−1
Appearance White deliquescent crystalline powder
Density 1.57 g/cm3 (25 °C (77 °F; 298 K))[1]
Melting point 303–307 °C (577–585 °F; 576–580 K)[1]
Boiling point Decomposes
  • 216.7 g/100 mL (0.1 °C (32.2 °F; 273.2 K))
  • 233.7 g/100 mL (10 °C (50 °F; 283 K))
  • 268.6 g/100 mL (25 °C (77 °F; 298 K))
  • 320.8 g/100 mL (40 °C (104 °F; 313 K))
  • 390.7 g/100 mL (96 °C (205 °F; 369 K))[2]
Solubility in methanol
  • 24.24 g/100g (15 °C (59 °F; 288 K))
  • 53.54 g/100g (73.4 °C (164.1 °F; 346.5 K))[3][verification needed]
Solubility in ethanol 16.3 g/100g[2]
Solubility in acetic acid 20.95 g/100g (28.03 °C (82.45 °F; 301.18 K))[3][4]
Solubility in dimethylformamide 0.09 g/100g[3]
Solubility in sulfur dioxide 0.006 g/100g (0 °C (32 °F; 273 K))[3]
Solubility in liquid ammonia 1.026 g/100g (−33.9 °C (−29.0 °F; 239.2 K))[3]
Vapor pressure < 0.0000001 hPa[1]
Acidity (pKa) 4.76
Structure
Monoclinic
Thermochemistry[5]
109.38 J/(mol × K)
150.82 J/(mol × K)
−722.6 kJ⋅mol−1[3]
Enthalpy of fusion (ΔfH⦵fus)
 22 kJ⋅mol−1[3]
Pharmacology
B05XA17 (WHO)
Hazards[6]
GHS labelling:
Warning
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 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
1
1
1
Lethal dose or concentration (LD, LC):
3250 mg/kg (oral, rat)
Related compounds
Other anions
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
Close

Preparation

It can be prepared by treating a potassium-containing base such as potassium hydroxide with acetic acid:

CH3COOH + KOH → CH3COOK + H2O

This sort of reaction is known as an acid-alkali reaction.

At saturation, the sesquihydrate in water solution (2CH3COOK·3H2O) begins to form the semihydrate (2CH3COOK·H2O) at 41.3 °C (106.3 °F).[2]

Applications

Deicing

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 advantages over chlorides of being less aggressive on soils and much less corrosive: for this reason, it is one of the preferred substances for removal of ice from airplanes and airport runways.[7][8]

Fire extinguishing

Potassium acetate is the extinguishing agent used as a component in some Class K fire extinguishers[9] because of its ability to cool and form a crust over burning oils.[citation needed]

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; it is also approved for usage in the USA, Australia, and New Zealand.[10][11][12]

Medicine and biochemistry

In molecular biology, potassium acetate is used to precipitate Sodium dodecyl sulfate (SDS) and SDS-bound proteins to allow their removal from DNA.[citation needed]

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.[13] This process was used to soak Lenin's corpse.[14]

Industry

Potassium acetate is used as a catalyst in the production of polyurethanes.[15]

Use in executions

Potassium acetate was incorrectly used in place of potassium chloride when putting a prisoner to death in Oklahoma in January 2015. 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.[16][17]

In August 2017, the U.S. state of Florida used potassium acetate (intentionally) in the execution of Mark James Asay.[18]

Historical

Potassium acetate 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.[19] In 1760 it was used in the preparation of Cadet's fuming liquid ((CH3)2As)2 + ((CH3)2As)2O, the first organometallic compound ever produced.[citation needed]

References

External links

Related Articles

Wikiwand AI