Potassium Fluoride KF · CAS 7789-23-5

What is Potassium Fluoride?

Potassium Fluoride is the simple inorganic salt of potassium and fluoride, formula KF, supplied as a white crystalline solid. It is highly water-soluble and, unlike hydrofluoric acid or other reactive fluorinating gases, is handled and stored as an ordinary free-flowing powder.

Its largest specialty use is as the fluoride source in Halex (halogen-exchange) nucleophilic aromatic substitution reactions, where an activated chloro- or nitro-aromatic is heated with KF, typically with a phase-transfer catalyst or in a polar aprotic solvent, to swap chlorine for fluorine. This is the route by which many of the fluoroaromatic intermediates used across the pharmaceutical and agrochemical industries, including several fluoronitrobenzenes and fluoroanilines, are manufactured at scale.

Beyond fine-chemical synthesis, potassium fluoride is also used as a flux in metallurgy and brazing, as an etching and frosting agent for glass, and historically as a wood preservative, owing to its ability to lower melting points of oxide films and its biocidal activity at higher concentrations.

Handling follows standard precautions for a toxic, corrosive inorganic fluoride — chemical-resistant gloves, eye protection, adequate ventilation, and storage away from strong acids, which liberate hydrogen fluoride gas on contact.

Why Potassium Fluoride specifically

• The standard Halex fluoride source. KF is the most widely used inorganic fluoride for nucleophilic aromatic fluorination, converting activated chloroaromatics to their fluoro analogues.
• Handled as a solid, not a gas or acid. Unlike HF or fluorine gas, KF is a free-flowing crystalline powder, which simplifies dosing, storage and transport relative to more hazardous fluorinating agents.
• Cost-effective fluoride source. Compared with other metal fluorides (such as caesium fluoride), KF offers a favourable balance of reactivity and cost for bulk Halex chemistry.
• Multi-industry utility. The same material serves as a Halex reagent in fine-chemical plants and as a flux/etching agent in metallurgy and glass processing.

How Potassium Fluoride is Manufactured

Potassium fluoride is produced by straightforward acid-base neutralisation chemistry rather than a complex multi-step synthesis, so supply reliability depends mainly on hydrofluoric acid availability and crystallisation/drying capacity.

• Neutralisation. Hydrofluoric acid is reacted with a potassium base — typically potassium carbonate or potassium hydroxide — to form potassium fluoride in aqueous solution.
• Concentration and crystallisation. The solution is concentrated and cooled to crystallise potassium fluoride, which is then separated from the mother liquor.
• Drying. The crystals are dried to the target moisture specification; for Halex-grade material, drying is tightly controlled since residual moisture can interfere with the fluorination reaction.
• Milling and quality release. The dried solid is milled to the required particle-size distribution, tested, and packed under conditions that keep it from reabsorbing atmospheric moisture.

Typical Commercial Specification

Figures below are representative of commercial, Halex-grade potassium fluoride. Tell us your application — fine-chemical synthesis, metallurgical flux, or glass processing — and we will advise on the grade to order against.

Physical & Chemical Properties

Behaviour in the process

Potassium fluoride's reactivity pattern is what Halex chemistry and metallurgical/glass users rely on:

• Nucleophilic fluoride source. In polar aprotic solvents or with phase-transfer catalysis, the fluoride ion displaces chlorine or other leaving groups from activated aromatic substrates.
• Hygroscopicity. Readily absorbs atmospheric moisture, which both reduces reactivity in Halex chemistry and causes caking in storage if containers are not kept sealed.
• Reacts with strong acids. Liberates hydrogen fluoride gas on contact with strong acids — a key handling and compatibility consideration.

Potassium Fluoride and Alternative Fluoride Sources

Choosing a fluoride source for Halex chemistry comes down to reactivity, cost and the specific substrate being fluorinated.

Stated plainly: for most commercial Halex routes converting activated chloronitrobenzenes or similar substrates to their fluoro analogues, standard KF is the default economical choice.

Industries We Supply Potassium Fluoride To

The same potassium fluoride feeds a fine-chemical plant running Halex fluorination and a metallurgical shop using it as a flux. What changes is the grade, particle size and documentation each requires.

Where Potassium Fluoride is Used

In the Halex reaction

Potassium fluoride supplies the nucleophilic fluoride ion that displaces chlorine from an activated aromatic ring, typically under elevated temperature with a polar aprotic solvent such as sulfolane or DMSO, or with a phase-transfer catalyst. This route underlies the commercial manufacture of several fluoronitrobenzene and fluoroaniline intermediates — the Halex step is often the most capital- and energy-intensive stage of the whole synthesis, which is why fluoride-source quality and consistency matter.

Quality Control & Testing

Every lot is released against a batch-specific Certificate of Analysis, with moisture content reported alongside the main assay because residual moisture directly affects Halex reaction performance.

• KF content — by titration, the primary grade measure.
• Moisture content — critical for Halex-grade material; reported separately from bulk assay.
• Particle size distribution — affects reaction surface area and handling behaviour.
• Water insolubles — a purity and process-contamination check.

Common Process Problems & Likely Causes

Packaging, Storage & Shipping

• Standard packing. HDPE drums or moisture-barrier bags, typically 25 – 200 kg net, with larger bulk formats on contract supply.
• Moisture protection. Keep sealed at all times — KF is hygroscopic and will cake or lose Halex reactivity if exposed to humid air.
• Material compatibility. Keep away from strong acids, which liberate hydrogen fluoride gas on contact.
• Storage conditions. Store in a cool, dry, well-ventilated area, off the floor and away from incompatible acids.
• Transport classification. Commonly shipped under UN 1812, Class 6.1, Packing Group III — confirm against your own current SDS before shipping.

Hazards & Safe Handling

Potassium Fluoride is toxic if swallowed, causes skin and serious eye irritation, and may cause respiratory irritation. Standard precautions for a toxic, corrosive inorganic fluoride and good laboratory and plant practice apply throughout handling.

• Skin and eye contact. Chemical-resistant gloves and goggles are standard practice; rinse thoroughly with water on contact and seek medical attention for eye exposure.
• Inhalation. Use adequate ventilation and dust control when handling the powder; avoid breathing dust.
• PPE. Chemical-resistant gloves, safety goggles or a face shield and, where dust is generated, a suitable respirator.
• Acid contact. Never mix with strong acids — this liberates toxic, corrosive hydrogen fluoride gas.

Regulatory & Compliance Notes

Potassium fluoride is a registered, widely traded inorganic fluoride. Because obligations differ by territory and use, the notes below are orientation rather than legal advice.

• GHS classification. Classified as toxic if swallowed, causing skin and serious eye irritation, and potential respiratory irritation (Signal word: Danger); the SDS carries the full hazard statements for your grade.
• REACH and chemical inventories. Registered under EU REACH and listed on major chemical inventories.
• Dangerous goods transport. Commonly shipped as UN 1812, Class 6.1, Packing Group III. Confirm with your logistics/EHS team against your current SDS before shipping.
• HS code. Commonly declared under the fluorides heading (HS 2826); confirm the exact tariff line with your customs broker for your jurisdiction.

We Supply Potassium Fluoride Worldwide

Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Potassium Fluoride from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation and freight so the material arrives ready to use.

• Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
• Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged as routing allows.
• Documentation. Commercial invoice, packing list, certificate of origin, COA and SDS issued as a complete set.
• Flexible volumes. From trial quantities up to repeat bulk shipments on a supply contract.

Buying Potassium Fluoride from Chelora

We are an independent sourcing and supply partner. For this product that means settling three things at enquiry: the grade and moisture specification your application needs, the packing format, and the quantity you are buying.

• Documentation on every lot. Batch-specific COA with assay and moisture content, plus the current SDS.
• Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
• Quantities. Trial quantities through to larger bulk shipments on contract supply.
• Inspection. Independent third-party inspection available at loading when the contract requires it.
• Related fluoroaromatic intermediates. Many of the fluoronitrobenzenes and fluoroanilines in our catalog are themselves made using Halex chemistry with KF — ask us about the full chain from fluoride source through to finished intermediate.

How ordering works

• Send the enquiry. Grade, moisture specification, quantity, destination port and the Incoterm you buy on.
• We quote. Price, lead time, packing format and a sample COA, normally within one working day.
• Qualify the supply. For first orders or Halex-grade applications, we share the analysis so your technical team can sign off before you commit.
• Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
• Ship and document. Packed, labelled and loaded with the full export document set, and tracked through to arrival.

Related Fluoroaromatic Intermediates