Potassium fluoride

Chemical Properties

Potassium fluoride, KF, is a colorless, deliquescent crystalline solid that has a melting point of 846 °C(1550 °F). Potassium fluoride has a salty taste and is poisonous. It is soluble in water,but insoluble in alcohol. Potassium fluoride is used in etching glass,preservatives, and insecticides.

Physical and Chemical Properties

Potassium fluoride is basis raw material of manufacturing fluoride, chemical formula is KF. Molecular weight is 58.10. It is colorless cubic crystal or white powder. It is poisonous! It is deliquescent. Taste is salty. Specific gravity is 2.48. Melting point is 858℃. Boiling point is 1505℃. It is soluble in water. It was dissolved in hydrofluoric acid and ammonia. It is insoluble in ethanol, acetone. Aqueous solution is alkaline and it can corrode glass and porcelain. It can cause irritation for human skin, mucous membrane and eye. When belows 40.2℃, it can crystallize in an aqueous solution to give dihydrate KF·2H2O, which is monoclinic, it is self-dissolved crystalline water at 41℃. It can be obtained by the thermal decomposition of potassium hydrogen fluoride or potassium carbonate (or potassium hydroxide) and hydrofluoric acid (40% or anhydrous). It can be used for glass engraving, food preservation, it can be also used as welding flux, fluoride, pesticides,etc.

Figure 1 the structural formula of potassium fluoride.

Uses

Anhydrous Potassium fluoride is used in organic synthesis as a catalyst for various reactions, or to introduce fluorine into organic molecules. For example, fluoro compounds can be prepared by replacing labile chlorine atoms by fluorine atoms, as in the manufacture of sodium fluoroacetate, a rat poison. The nucleophilic strength of F− and the solubility of KF in aprotic organic solvents may be improved by using crown ethers. The “naked” fluoride ion obtained is an efficient fluorinating agent.

Preparation

Potassium fluoride is prepared by reacting potassium carbonate (or KOH) with aqueous hydrofluoric acid. Care is necessary in handling the anhydrous salt, to prevent its hydration.

Chemical Properties

White, crystalline, deliquescent powder; sharp saline taste.Soluble in water and hydrogen fluoride, insoluble in alcohol.

Chemical Properties

Potassium fluoride is a white crystalline solid.

Uses

Uses

Potassium fluoride is used in metal finishing, batteries, coatings and photographic chemicals. It is utilized for the study of ion-specific swelling and de-swelling of ampholytic polymer gels as well as in the measurement of electronic polarizabilities of ions in polymers of alkali halides. It finds application in the electronic industry as a metal surface treatment product. It is used as a preservative, a food additive, a catalyzer and a water absorbing agent. In the Finkelstein reaction, it is actively involved in the conversion of chlorocarbons to fluorocarbons using polar solvents like dimethyl formamide and ethylene glycol.

Definition

ChEBI: Potassium fluoride is a fluoride salt having K+ as the counterion. It has a role as a poison. It is a fluoride salt and a potassium salt.

Reactivity Profile

Potassium fluoride reacts with acids to evolve corrosive and toxic hydrogen fluoride. Aqueous solutions corrode glass and consequently are prepared and stored in polyethylene containers. The pure solid may be stored in glass containers. Reacts violently with (Pt + BrF3). [NTP 1992].

Hazard

Toxic by ingestion and inhalation, strong irritant to tissue.

Health Hazard

TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Fire Hazard

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.

Safety Profile

Poison by ingestion and intraperitoneal routes. Moderately toxic by subcutaneous route. Experimental teratogenic effects. A corrosive irritant to the eyes, skin, and mucous membranes. Mutation data reported. A very reactive material. When heated to decomposition it emits toxic fumes of K2O and F-. Used in etchmg glass, as a presewative, as an insecticide, and in organic synthesis. See also FLUORIDES and HYDROFLUORIC ACID.

Potential Exposure

Potassium fluoride is used in etching glass; as a preservative and insecticide.

Shipping

UN1812 Potassium fluoride, solid, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Incompatibilities

Incompatible with strong acids; reacts releasing hydrogen fluoride. Aqueous solutions corrode glass and consequently are prepared and stored in polyeth- ylene containers. The pure solid may be stored in glass containers. Reacts violently with (Pt 1 BrF 3 )

Toxics Screening Level

The initial threshold screening level (ITSL) for potassium fluoride is 76 μg/m3 based on an eight hour averaging time.