Key Property Q&A Is potassium hydroxide soluble in water? Yes - KOH dissolves readily in water (121 g/100 mL at 25°C) with a strongly exothermic reaction; always add KOH to water, never the reverse.  |  Is KOH soluble in ethanol / methanol? Yes - potassium hydroxide in ethanol and potassium hydroxide in methanol solutions are widely used in chemical synthesis and biodiesel production.  |  Is potassium hydroxide dangerous? KOH is a corrosive substance (GHS Category 1 skin/eye corrosion, UN 1813). It causes severe burns on contact. Full PPE is mandatory.  |  Potassium hydroxide vs sodium hydroxide? Both are strong bases, but KOH produces softer soaps, is more soluble in organic solvents, and generates potassium salts. NaOH is lower cost and more common for industrial neutralization.

Specification	Industrial Grade Chemical / Textile / Battery	Food Grade E525 / FCC / GB 25575	Electronic Grade Semiconductor / Wafer Etching
KOH Assay	≥ 90.0% or ≥ 95.0%	≥ 95.0%	≥ 99.0%
Carbonate (K₂CO₃)	≤ 1.5%	≤ 1.0%	≤ 0.5%
Chloride (Cl⁻)	≤ 0.01%	≤ 0.005%	≤ 0.001%
Heavy Metals (Pb)	≤ 0.002%	≤ 0.001%	≤ 0.0001%
Iron (Fe)	≤ 0.001%	≤ 0.0005%	≤ 0.0001%
Sodium (Na)	≤ 1.0%	≤ 0.5%	≤ 0.1%
Moisture	≤ 1.0%	≤ 0.8%	≤ 0.5%
Available Forms	Flakes, Pellets, Powder, Liquid (45%–50%)	Flakes, Pellets	Flakes, Ultra-pure Solution
Packaging	25 kg bag / drum 1000 kg IBC tote ISO tank (liquid)	25 kg food-grade bag	25 kg ultra-clean bag IBC tote (solution)

1. Soap & Detergent Manufacturing - Liquid Soap & Saponification

Potassium hydroxide is the alkali of choice for liquid soap and shampoo production. While sodium hydroxide produces hard bar soap, potassium hydroxide soap (potash soap) yields soft, water-soluble soap pastes ideal for liquid hand washes, shampoos, and industrial cleaning concentrates. In saponification, fatty acids or triglycerides react with KOH solution to form potassium soap salts. Industrial-grade KOH flakes (90–95%) are standard for bulk soap manufacturing; a potassium hydroxide solution (typically 45–50%) is used for continuous saponification lines.

KOH is also used in surface cleaning formulations: its high alkalinity effectively removes grease, oils, biofilms, and mineral deposits from industrial equipment, pipelines, and food processing surfaces (potassium hydroxide cleaning).

Reference: PubChem - Potassium Hydroxide (NIH) ↗

2. Chemical Industry - Potassium Salt Production & Synthesis

KOH is a foundational raw material for manufacturing a wide range of potassium salts: potassium carbonate (K₂CO₃), potassium permanganate (KMnO₄), potassium phosphate, and potassium acetate. It is used as a catalyst, neutralizing agent, and pH adjuster across organic synthesis, biodiesel production (transesterification with KOH in methanol or ethanol), and specialty chemical manufacturing.

Potassium hydroxide in ethanol (ethanolic KOH) is a classic reagent for elimination reactions (E2) and ester hydrolysis in organic chemistry. Potassium hydroxide in methanol (methanolic KOH) is the standard catalyst for biodiesel production via transesterification of vegetable oils.

3. Food & Beverage Industry - Food Additive E525

Food-grade potassium hydroxide is approved as a food additive E525 for pH control, acidity regulation, and processing aid applications. It is used in the production of food preservatives (potassium sorbate), flavor enhancers, cocoa processing (Dutch-process cocoa), and dairy product manufacturing. It meets the purity requirements of FCC (Food Chemicals Codex), FAO/WHO, and GB 25575 standards.

Reference: FAO/WHO JECFA Food Additive Standards ↗

4. Pharmaceutical Industry - Drug Synthesis & pH Control

KOH is used in pharmaceutical manufacturing for synthesizing potassium-based APIs including progesterone, spironolactone, and various antibiotics. It serves as a neutralizing agent, reaction catalyst, and raw material for potassium salt intermediates. Pharmaceutical-grade KOH complies with Ph Eur, BP, and USP pharmacopoeia monographs, with strict limits on heavy metals and sodium content to ensure drug safety.

5. Electronics & Semiconductor - Wafer Etching & Cleaning

Electronic-grade KOH (≥99.0%) is a key etchant for anisotropic silicon wafer etching in MEMS (microelectromechanical systems) and semiconductor device fabrication. KOH etches silicon along crystallographic planes with high selectivity, enabling precise microfabrication of sensors, accelerometers, and microfluidic devices. Its ultra-low metal impurity specification prevents contamination of 8-inch and 12-inch wafer production lines.

KOH solution is also used as an alkaline electrolyte in nickel-cadmium (NiCd), nickel-metal hydride (NiMH), and alkaline zinc-manganese batteries, where its high ionic conductivity and electrochemical stability are essential.

Reference: SEMI Standards - Electronic Chemicals ↗

6. Agriculture, Textile & Other Industries

In agriculture, KOH is used to produce potassium fertilizers (potassium nitrate, potassium phosphate), soil pH adjusters, and agricultural pesticide intermediates, directly supporting crop yield and quality. In the textile industry, KOH is used in cotton mercerization and as a scouring agent to improve fabric lustre and dye uptake. It is also used in biodiesel production as a transesterification catalyst, and in fuel cells as an alkaline electrolyte solution.

Property	Potassium Hydroxide (KOH)	Sodium Hydroxide (NaOH)
Molecular Weight	56.11 g/mol	40.00 g/mol
Soap Type Produced	Soft / liquid soap	Hard bar soap
Solubility in Ethanol	High	Low
Salts Produced	Potassium salts	Sodium salts
Relative Cost	Higher	Lower
Key Advantage	Liquid soap, biodiesel, electronics, agriculture	Bar soap, paper, general neutralization

⚠️ CRITICAL SAFETY NOTE: Potassium hydroxide is a corrosive substance (UN 1813 / UN 1814, Class 8) that causes severe burns to skin, eyes, and mucous membranes. Dissolution in water is strongly exothermic. Always add KOH to water - never water to KOH. Do not mix with acids without proper controls.

Bulk pricing tips: Orders above 20 MT (FCL) typically reduce potassium hydroxide price per kg by 8–15% versus LCL shipments. Long-term annual contracts (100+ MT/year) unlock priority allocation and locked pricing terms. Tank delivery of KOH liquid solution (45%) is the most cost-effective form for large-volume soap and chemical producers. Request a custom KOH price quote →

Q: What is caustic potash, and is it the same as potassium hydroxide?

Yes - caustic potash is the common industrial name for potassium hydroxide (KOH, CAS 1310-58-3). The term "caustic" reflects its strongly corrosive nature. Caustic potash flakes and caustic potash pellets are standard commercial forms. It is distinct from "caustic soda" (sodium hydroxide, NaOH), though both are strong bases with similar but not identical applications.

Q: What are the main forms of potassium hydroxide - flakes, pellets, or liquid?

KOH flakes (irregular flat chips, ~3–5 mm) are the most common solid form - easy to handle and dissolve. KOH pellets (uniform spheres, ~1–3 mm) offer better flowability for automated dosing systems and are preferred in pharmaceutical and food applications. KOH powder (fine grind) is used in specialty coating and ceramic applications. KOH liquid solution (typically 45–50% aqueous) is the most economical form for large-volume users such as soap manufacturers and chemical plants, eliminating the need for dissolution equipment.

Q: How do I make potassium hydroxide solution (KOH solution)?

To prepare a potassium hydroxide solution: always add KOH solid to water - never add water to KOH (to prevent dangerous spattering from the exothermic reaction). Use a polypropylene or stainless steel vessel. For a 10% KOH solution, dissolve 100 g KOH flakes in 900 mL distilled water with stirring; allow to cool before use. For concentrated solutions (45%+), use cooling and ventilation. Always wear full PPE. Common concentrations: 10%, 20%, 45%, 50% w/w. UN 1814 classification applies to solutions with KOH > 2%.

Q: Is potassium hydroxide the same as lye? Can I use it for soap making?

Yes - potassium hydroxide lye is the correct alkali for making liquid soap. When fats or oils are saponified with KOH, the resulting potassium soap salts are soft and water-soluble, producing liquid or gel-textured soaps. For hard bar soap, sodium hydroxide (NaOH) lye is used instead. Food-grade or high-purity KOH (≥90%) is recommended for cosmetic soap making to avoid heavy metal contamination in the final product. Our Industrial Grade KOH flakes/pellets are widely used by soap manufacturers globally.

Q: What is the UN number for potassium hydroxide, and how is it classified for shipping?

Solid potassium hydroxide (flakes, pellets) is classified as UN 1813, Class 8 (Corrosive), Packing Group II. Potassium hydroxide solution (aqueous, >2% KOH) is classified as UN 1814, Class 8, Packing Group II or III depending on concentration. All shipments require proper GHS hazard labeling (corrosion pictogram), emergency contact information, and a Safety Data Sheet (SDS). We handle all documentation for international export compliance (REACH, TSCA, IMO/IMDG).

Q: What is the difference between KOH 90%, KOH 95%, and KOH 99%?

KOH 90% (industrial grade) is standard for bulk chemical processes where high purity is not critical. KOH 95% (industrial/food) is suitable for most soap manufacturing, food processing, and pharmaceutical applications. KOH 99% (electronic grade, anhydrous) is required for semiconductor wafer etching, battery electrolytes, and precision chemical synthesis where minimal carbonate and metal impurities are essential. The difference in assay reflects mainly water content and carbonate levels.

Q: How is potassium hydroxide manufactured?

KOH is produced commercially by the chloralkali process - electrolysis of potassium chloride (KCl) brine using membrane cell or diaphragm cell technology. The process yields KOH solution (typically 30–35% initial concentration, evaporated to 45–90%), chlorine gas (Cl₂), and hydrogen gas (H₂) as co-products. Modern membrane electrolysis technology produces higher-purity KOH with lower sodium content compared to older diaphragm processes, and is the method used by our partner manufacturers. China accounts for the majority of global KOH production capacity.