- Structure
- Nomenclature
- Properties
- Physical state
- Molecular weight
- Melting point
- Density
- Solubility
- pH
- Other properties
- Behavior when heated
- Obtaining
- Applications
- In various applications
- In the polymer industry
- In scientific and medical research laboratories
- In the industrial production of antibodies
- In antifreeze mixtures
- How it works as an antifreeze
- References
The potassium acetate is an organic compound consisting of a potassium ion K + and an acetate ion CH 3 COO -. Its chemical formula is CH 3 COOK, or KCH 3 COO, or also C 2 H 3 KO 2. It is a colorless or white crystalline solid, very soluble in water.
It is used to regulate the acidity of certain industrially processed foods. Due to its great affinity with water, it is used in laboratories or in certain processes to absorb water from other compounds, such as for dehydrating alcohol.
KCH 3 COO potassium acetate is used to regulate the acidity of some processed foods. Author: RitaE. Source: Pixabay.
Potassium acetate participates in some chemical reactions as an accelerator of these and in the synthesis of organic compounds. It also allows to increase the formation of antibodies (natural substances that fight infections) in industrial methods to produce them.
Its very low temperature properties make it a good candidate for use in ice melting mixes on concrete roads in very cold climates. According to consulted sources, it is also used in fire fighting equipment and in assemblies to observe cells in microscopes.
Structure
Potassium acetate is made up of a K + potassium cation and a CH 3 COO - acetate anion. The latter is the conjugate base of acetic acid CH 3 COOH. The acetate ion CH 3 COO - is formed by a methyl -CH 3 linked to a carboxylate -COO -.
The union between both ions is electrostatic or ionic, that is, the union between a positive and a negative ion.
Structure of potassium acetate CH 3 COOK. SSsilver. Source: Wikimedia Commons.
Nomenclature
- Potassium acetate
- Potassium ethanoate
- Potassium salt of acetic acid
- AcOK
- KOAc
Properties
Physical state
Colorless or white crystalline solid.
Molecular weight
98.14 g / mol
Melting point
292 ºC
Density
1.6 g / cm 3
Solubility
Very soluble in water: 256 g / 100 mL at 20 ° C.
pH
A 5% aqueous solution of potassium acetate has a pH of 7.5-9.0.
Other properties
Sometimes it has a faint vinegar smell. In 10% solution, it does not attack aluminum at room temperature but at 60-70 ° C the metal darkens and suffers pitting.
At concentrations of 20% or more, surface attack on aluminum occurs at any temperature.
Potassium acetate (AcOK) is highly soluble in water. It has a hydrate: KCH 3 COO.1,5H 2 O, which is the solid obtained when it crystallizes from the aqueous solutions of AcOK.
Behavior when heated
If the hydrated potassium acetate (AcOK) (KCH 3 COO.1,5H 2 O) is subjected to heating, when it reaches 40 ° C, it begins to lose the water of hydration.
KCH 3 COO. 1,5H 2 O → KCH 3 COO + 1,5H 2 O ↑
If anhydrous potassium acetate is heated (without water: KCH 3 COO), when it reaches 340 ° C it begins to decompose forming K 2 CO 3 potassium carbonate according to the following reaction:
2 KCH 3 COO + 4 O 2 → K 2 CO 3 + 3 H 2 O + 3 CO 2 ↑
Obtaining
It can be prepared by the action of potassium hydroxide KOH on various compounds, such as acetic acid CH 3 COOH, acetic anhydride (CH 3 CO) 2 O and ammonium acetate CH 3 COONH 4.
KOH + CH 3 COOH → CH 3 COOK + H 2 O
It can also be obtained by reacting potassium carbonate K 2 CO 3 or potassium bicarbonate KHCO 3 with acetic acid CH 3 COOH.
KHCO 3 + CH 3 COOH → CH 3 COOK + H 2 O + CO 2 ↑
Potassium acetate can be crystallized from an aqueous solution to obtain it in high purity.
Applications
In various applications
Potassium acetate is used in the processed food industry as an acidity regulator. It is used as a desiccant in chemical methods to measure the water vapor permeability of some fabrics.
It serves as a dehydrating agent for ethanol in the production of this alcohol starting from lignocellulose, a material derived from wood.
It is used to produce antibiotics and is widely used in fire fighting equipment.
In the polymer industry
It is used to recycle polyurethanes as it serves to catalyze or accelerate the hydrolysis and glycolysis reactions of said polymers so that they become alcohols and amines.
It is also used in the production of organic silicone resins.
In scientific and medical research laboratories
High purity potassium acetate is used in laboratories as a reagent in analytical chemistry. Also to carry out medico-scientific research.
In histopathology laboratories it serves to ensure a neutral pH medium in microscope setups.
Potassium acetate has many uses in chemical and medical research laboratories. Author: Michal Jarmoluk. Source: Pixabay.
It is used for the synthesis of heterocyclic organic compounds, which are compounds with different size cycles.
Certain microelectrodes that serve to study the electrical properties of cells, are filled with a concentrated solution of potassium acetate.
In the industrial production of antibodies
Potassium acetate is used for the large-scale production of monoclonal antibodies (which are those that come from the same stem cell) in cell cultures. It allows to stimulate the synthesis or formation of antibodies.
Antibodies are substances produced by some cells in the blood to fight infections from viruses or bacteria.
Artistic image of antibodies. Sodium acetate KCH 3 COO serves in the production of antibodies in large quantities. BlitzKrieg1982. Source: Wikimedia Commons. Although potassium acetate (AcOK) inhibits or slows cell growth and decreases cell density, the productivity of antibodies per cell increases.
Drawing of antibody attack against some bacteria. SA1590. Source: Wikimedia Commons.
In antifreeze mixtures
Potassium acetate has been used in anti-icing mixtures in order to use them to melt ice on roads and cement pavements and thus allow their safe use.
During the winter season the roads are filled with snow and ice. Potassium acetate can be helpful in such cases. Author: S. Hermann & F. Richter. Source: Pixabay.
The selection of potassium acetate (AcOK) for this application is due to the fact that a 50% by weight aqueous solution of AcOK is eutectic and has a melting point of -62 ° C. That means that even at temperatures as low as -62 ° C the solution remains molten.
A eutectic is a homogeneous mixture of components that has the lowest melting point of all possible mixtures of these, including that of the pure components.
How it works as an antifreeze
Potassium acetate (AcOK) has a very good ability to melt ice.
At -5 ° C it is capable of melting 11.5 kg of ice for each kg of AcOK. This property decreases as the temperature decreases, but even at -50 ° C it has the ability to melt 1.3 Kg of ice for every Kg of AcOH.
At -5 ° C this capacity is comparable to that of sodium chloride or table salt (NaCl), while from -30 ° C it far exceeds it.
Potassium acetate allows ice to melt on frozen roads. Author: Markus Sch. Source: Pixabay.
However, in the tests carried out with AcOK together with other compounds, a certain degree of corrosion of the cement surfaces was observed, for which reason it was considered to add anticorrosive agents to the antifreeze mixtures.
On the other hand, the mixture of potassium acetate (CH 3 COOK) with potassium formate (HCOOK) is an excellent antifreeze and does not require anticorrosive.
References
- Baker, FJ et al. (1976). Staining Procedures. Aqueous mountants. In Introduction to Medical Laboratory Technology (Fifth Edition). Recovered from sciencedirect.com.
- Hassan, AA et al. (2018). Indazoles: Synthesis and Bond-Forming Heterocyclization. In Advances in Heterocyclic Chemistry. Recovered from sciencedirect.com.
- US National Library of Medicine. (2019). Potassium acetate. Recovered from pubchem.ncbi.nlm.nih.gov.
- Das, A. and Alagirusamy, R. (2010). Moisture transmission. Desiccant inverted cup method. In Science in Clothing Comfort. Recovered from sciencedirect.com.
- Vargel, C. (2004). Carboxilic Acids and their Derivatives. Acetates. In Corrosion of Aluminum. Recovered from sciencedirect.com.
- Cuevas, J. (2014). Electrophysiological Recording Techniques. Intracellular Recording Techniques. In Reference Module in Biomedical Sciences. Recovered from sciencedirect.com.
- Fink, JK (2018). Poly (urethane) s. Recycling. Solvolysis. In Reactive Polymers: Fundamentals and Applications (Third Edition). Recovered from sciencedirect.com.
- Fong, W. et al. (1997). Optimization of monoclonal antibody production: combined effects of potassium acetate and perfusion in a stirred tank bioreactor. Cytotechnology 24: 47-54. Recovered from link.springer.com.
- Danilov, VP et al. (2012). Low-Temperature Anti-Icing Reagents in Aqueous Salt Systems Containing Acetates and Formiates. Theoretical Foundations of Chemical Engineering, 2012, Vol 46, No. 5, pp. 528-535. Recovered from link.springer.com.
- Fakeev, AAet al. (2012). Research and Development of Method for Potassium Acetate of High Purity. Journal of Applied Chemistry, 2012, Vol. 85, No.12, pp. 1807-1813. Recovered from link.springer.com.