Potassium hydroxide
[CAS# 1310-58-3]

Identification

• Classification: Inorganic chemical industry >> Inorganic base
• Name: Potassium hydroxide
• Synonyms: Caustic potash
• Molecular Formula: KOH
• Molecular Weight: 56.10
• CAS Registry Number: 1310-58-3
• EC Number: 215-181-3
• SMILES: [OH-].[K+]

Properties

• Density: 2.044
• Melting point: 360 °C
• Boiling point: 1320 °C
• Water solubility: soluble

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H290-H302-H314-H318
• Safety Statements: P234-P260-P264-P264+P265-P270-P280-P301+P317-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P321-P330-P363-P390-P405-P406-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1A	H314
Acute toxicity	Acute Tox.	4	H302
Serious eye damage	Eye Dam.	1	H318
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	3	H301
Specific target organ toxicity - single exposure	STOT SE	1	H370
Skin irritation	Skin Irrit.	2	H315
Aspiration hazard	Asp. Tox.	1	H304
Skin corrosion	Skin Corr.	1B	H314
Eye irritation	Eye Irrit.	2	H319
Skin corrosion	Skin Corr.	1	H314
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Skin corrosion	Skin Corr.	1C	H314
Acute toxicity	Acute Tox.	3	H302
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	3	H332
Acute toxicity	Acute Tox.	4	H332
Flammable liquids	Flam. Liq.	2	H225
Explosives	Expl.	1.1	H201
Acute toxicity	Acute Tox.	1	H312
Specific target organ toxicity - repeated exposure	STOT RE	1	H372

• Transport Information: UN 1813; UN 1814

Discovery and Applications

Potassium hydroxide (KOH), commonly known as caustic potash, is an inorganic compound of great industrial importance. It was first isolated in 1807 by the famous British chemist Sir Humphry Davy through the electrolysis of potassium carbonate. Davy's work laid the foundation for the production of potassium-based compounds and emphasized the role of potassium hydroxide as a strong base.

Potassium hydroxide is a white, hygroscopic solid that readily absorbs moisture from the air. It is highly soluble in water, forming a strongly alkaline solution with a pH of about 14. The compound has a melting point of 360°C and is used in a variety of chemical reactions due to its alkalinity and reactivity.

Potassium hydroxide has a wide range of uses in industrial processes. KOH is the primary reagent in the production of various potassium salts, including potassium carbonate and potassium sulfate. These salts are essential for fertilizers, detergents, and other industrial products. It is used in the manufacture of liquid and soft soaps. KOH saponifies fats and oils to produce potassium salts of fatty acids, which contribute to the cleaning properties of soaps.

In the chemical industry, potassium hydroxide plays a variety of roles. KOH is used as a reagent in various chemical syntheses, including the production of biodiesel through transesterification of fats and oils. It also aids in the preparation of other potassium compounds and organic chemicals. It is used to adjust the pH of solutions in chemical processes, ensuring optimal conditions for reactions and product stability.

In agriculture, potassium hydroxide is used to adjust the pH of alkaline soils, making them more suitable for growing crops. Proper pH increases nutrient availability and improves soil health. KOH is used to produce potassium-based fertilizers, which are essential for plant growth and development. Potassium improves plant disease resistance, enhances drought tolerance, and increases overall crop yields.

Potassium hydroxide is used in food processing as a food additive (E525) to adjust acidity and as a pH control agent in various foods. It helps maintain the desired texture and stability of processed foods. KOH is used in the production of foods such as olives to aid in the pickling process by neutralizing acids and improving texture.

In the laboratory, potassium hydroxide is used in titrations and other analytical procedures to determine the concentration of acidic substances in a sample. It provides precise control of pH during analytical procedures. It can be used as a basis for a variety of research applications, including the synthesis of compounds and the study of reaction mechanisms.

Because potassium hydroxide is a strong base, it should be handled with care, using gloves, goggles, and protective clothing to prevent skin and eye contact. Work in a well-ventilated area or use appropriate respiratory protection to avoid inhaling dust or fumes. Store KOH in a sealed container in a cool, dry place away from moisture and incompatible materials (such as acids).

Potassium hydroxide is generally safe for the environment if used properly. It is easily neutralized in the environment, breaking down into less harmful potassium salts and water. Steps should be taken to prevent large-scale spills, as high concentrations can affect soil and water quality.

References

2002. Textural and Chemical Characterizations of Adsorbent Prepared from Palm Shell by Potassium Hydroxide Impregnation at Different Stages. Journal of Colloid and Interface Science, 254(2).
DOI: 10.1006/jcis.2002.8587

2023. Preparation and Characterization of Adsorbent from Oil Palm Empty Fruit Bunches Activated with KOH. The 6th Mechanical Engineering, Science and Technology (MEST 2022) International Conference.
DOI: 10.2991/978-94-6463-134-0_16

2023. Synthesis of Diethanolamide Surfactant from Palm Oil by Esterification and Amidation Processes. The 6th Mechanical Engineering, Science and Technology (MEST 2022) International Conference.
DOI: 10.2991/978-94-6463-134-0_9