Аммоний фтористый

Химические свойства

Ammonium fluoride (NH4F) is a white crystalline salt that is soluble in cold water. It is unstable and emits a strong odor of ammonia. Ammonium fluoride is manufactured and sold in solid form or in aqueous solutions. Its applications include glass etching, wood preservation, and serving as a mordant in the textile industry.

Физические свойства

White, deliquescent, crystalline solid; occurs in various forms, as granular powder (commercial products), needles or leaflets, or hexagonal prism (formed on sublimation and condensation); density 1.009 g/cm³ at 25°C; decomposes on heating; highly soluble in cold water (100g/100g at 0°C); decomposes in hot water; slightly soluble in alcohol, insoluble in liquid ammonia.

Использование

It is used for etching of glass, preservation of food, in printing textile, and as mothproofing agent. It is used in chemical analysis and in brewing. It is used in the synthesis of NaHoF4 and NaEuF4, which are important in solid state lasers as well as photoluminescence. The fluoride ion is used as a base and nucleophile in organic synthesis. Ammonium fluoride providee safe deprotection strategy for the tert-butyldimethylsilyl (TBS) group during RNA synthesis.

Подготовка

Anhydrous ammonium fluoride is prepared by reacting anhydrous NH3 and HF or by heating aqueous solutions of NH4F at reduced pressure, so that a mixture of H2O and NH3 is distilled.

Определение

ChEBI: Ammonium fluoride is a fluoride salt having ammonium (NH4+) as the counterion. It is an ammonium salt and a fluoride salt.

Общее описание

Ammonium fluoride is a white crystalline solid. It is soluble in water. It is noncombustible. It is corrosive to aluminum. It is used in chemical analysis, in brewing, and as a preservative for wood.

Реакции воздуха и воды

Dissolves in water and forms dilute solution of hydrofluoric acid. May corrode glass, cement, and most metals [USCG, 1999]. Water soluble.

Профиль реактивности

Salts, basic, such as Ammonium fluoride, are generally soluble in water. The resulting solutions contain moderate concentrations of hydroxide ions and have pH's greater than 7.0. They react as bases to neutralize acids. These neutralizations generate heat, but less or far less than is generated by neutralization of the bases in reactivity group 10 (Bases) and the neutralization of amines. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible.

Опасность

Corrosive to tissue.

Угроза здоровью

Inhalation of dust may cause irritation of respiratory system. Ingestion is harmful; readily soluble fluorides may be fatal if relatively small quantities are swallowed. Contact with eyes causes local irritation of the mucous membrane. Contact with skin may cause burns. High concs. of fluorine in the urine have been reported following skin contact.

Профиль безопасности

Poison by subcutaneous and intraperitoneal routes. See also FLUORIDES. When heated to decomposition it emits very toxic fumes of F-, NO,, and NH3. Incompatible with ClF3

Возможный контакт

Ammonium fluoride is used in printing and dyeing textiles; glass etching, moth-proofing and wood preserving; in analytical chemistry, agriculture, antiseptic in brewing.

Перевозки

UN2505 Ammonium fluoride, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Несовместимости

Acids, alkalis, chlorine trifluoride. Corrodes glass, cement, most metals.

Утилизация отходов

Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal.