Potassium hydroxide

Potassium hydroxide (CAS 1310-58-3), also known as potash lye and designated E525 in food applications, is a strong inorganic alkali.

Where is Potassium hydroxide used?

• Soap and detergent manufacturing: alkali for soft and liquid soaps
• Food processing: acidity regulator in cocoa treatment, noodle production and confectionery
• Fertilizers: potassium source in liquid nutrient formulations
• Pulp and paper: fiber processing and bleaching
• Water treatment: pH correction and pipe corrosion prevention
• Water treatment: regulation of pH and removal of heavy metals, CO2, and other impurities.
• It also serves as a pH regulator, saponification agent and chemical intermediate where sodium-based alternatives are unsuitable.

Formulation notes

• Reacts with ammonium salts, releasing ammonia and creating a fire risk.
• Never add water to potassium hydroxide; for solutions or dilutions always add it slowly to the water.

Typical specification

• Water solubility: 110 g/100 ml at 25°C (very high).
• Most commonly available as a 45 to 50% concentrated solution.
• Available as a 28% w/w aqueous solution containing 72% w/w water.
• The 28% aqueous solution is also designated 5N.

Regulatory status

• Classified as harmonized under EU Regulation 1272/2008 (CLP).
• Potassium hydroxide solution has UN number 1814, hazard class 8, packing group II-III.
• Carries hazard statement H314, causing severe skin burns and serious eye damage.
• EU CLP harmonised classification index number: 019-002-00-8.

Storage, packaging and handling

• When moist, attacks metals such as aluminum, tin, lead, and zinc, producing flammable hydrogen.
• Store separated from food and feed, strong acids and metals, only in its original packaging, dry, well closed, in an area without drains or sewer access.
• Store only in the original container, dry, well closed, in an area without access to drains or sewers.

Frequently asked questions about Potassium hydroxide

How does potassium hydroxide behave when dissolved in water?

Potassium hydroxide is a strong alkali that dissociates completely in water into potassium and hydroxide ions; dissolution is strongly exothermic.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.