Алюминия хлорид

Химические свойства

Aluminum chloride is a noncombustible but highly reactive whitish-gray, yellow, or green powder or liquid. Strong, acidic, irritating odor like hydrochloric acid.The vapor consists of double molecules Al2Cl6 . Soluble in water.

Использование

A yellowish-white crystalline or granular powder made by passing chlorine gas over alumina in a heated state and collecting the product by sublimation. Aluminum chloride was occasionally used in gold and platinum toning baths.

Определение

aluminium chloride: A whitishsolid, AlCl₃, which fumes in moist airand reacts violently with water (togive hydrogen chloride). It is knownas the anhydrous salt (hexagonal; r.d.2.44 (fused solid); m.p. 190°C (2.5atm.); sublimes at 178°C) or the hexahydrateAlCl₃.6H₂O (rhombic; r.d.2.398; loses water at 100°C), both ofwhich are deliquescent. Aluminiumchloride may be prepared by passinghydrogen chloride or chlorine overhot aluminium or (industrially) bypassing chlorine over heated aluminiumoxide and carbon. The chlorideion is polarized by the smallpositive aluminium ion and thebonding in the solid is intermediatebetween covalent and ionic. In theliquid and vapour phases dimer moleculesexist, Al₂Cl₆, in which thereare chlorine bridges making coordinatebonds to aluminium atoms (seeformula). The AlCl₃ molecule can alsoform compounds with other moleculesthat donate pairs of electrons(e.g. amines or hydrogen sulphide);i.e. it acts as a Lewis acid. At hightemperatures the Al₂Cl₆ molecules inthe vapour dissociate to (planar)AlCl₃ molecules. Aluminium chlorideis used commercially as a catalyst inthe cracking of oils. It is also a catalystin certain other organic reactions,especially the Friedel–Craftsreaction.

Общее описание

Aluminum chloride may be manufactured by chlorination of liquid aluminum in ceramic lined reaction vessels at 600-700^oC.

Профиль реактивности

ALUMINUM CHLORIDE behaves as an acidic salt. Self-reactive. After long storage in closed containers, explosions often occur upon opening [Chem. Abst. 41:6723d 1947]. Can cause ethylene(also other alkenes) to polymerize violently [J. Inst. Pet. 33:254 1947]. Causes ethylene oxide to rearrange and polymerize, liberating heat [J. Soc. Chem. Ind. 68:179 1949]. Can catalyze violent polymerization of allyl chloride [Ventrone 1971]. Addition to nitrobenzene containing about 5% phenol caused a violent explosion [Chem. Eng. News 31:4915 1953]. Mixtures with nitromethane may explode when organic matter is present [Chem. Eng. News 26:2257 1948].

Опасность

Powerful irritant to tissue; moderately toxic by ingestion. Reacts violently with water, evolving hydrogen chloride gas.

Угроза здоровью

Contact with the skin or eyes in the presence of moisture causes thermal and acid burns.

Пожароопасность

Behavior in Fire: Reacts violently with water used in extinguishing adjacent fires

Воспламеняемость и взрывоопасность

Aluminum chloride is not flammable but reacts violently with water, so fires involving this substance should be extinguished with carbon dioxide or dry chemicals. Toxic fumes (HCl and reaction products) can be released during fires.

Промышленное использование

Aluminum chloride (AlCl3) is a volatile solid which sublimes at 458 K. The vapour formed on sublimation consists of an equilibrium mixture of monomers (AlCl3) and dimers (Al2Cl6). It is used to prepare the powerful and versatile reducing agent lithium tetrahydridoaluminate (LiAlH4). Aluminium trichloride (AlCl3) act as Lewis acids to a wide range of electron-pair donors, and this has led to their widespread use as catalysts. In the important Friedel-Crafts acylation, AlCl3 is used as a strong Lewis acid catalyst in order to achieve the acylation of an aromatic ring.

Профиль безопасности

Moderately toxic by ingestion. Experimental teratogenic and reproductive effects. Mutation data reported. The dust is an irritant by ingestion, inhalation, and skin contact. Highly exothermic polymerization reactions with alkenes. Incompatible with nitrobenaenes or nitrobenzene + phenol. Highly exothermic reaction with water or steam produces toxic fumes of HCl. See also ALUMINUM COMPOUNDS, CHLORIDES, and HYDROCHLORIC ACID.

Возможный контакт

It is used as ethylbenzene catalyst, dyestuff intermediate, and detergent alkylate; in making other chemicals and dyes, astringents, deodorants, in the petroleum refining, and the rubber industries

Описание

Алюминий хлористый является неорганическим соединением, солью алюминия и хлороводородной кислоты.
Получают хлорид алюминия в  результате реакции смеси хлора и окиси углерода на обезвоженный каолин  (белая глина) или боксит (алюминиевая руда).
Существует несколько видов данного реактива:
- алюминий хлористый безводный
- алюминий хлорид гексагидрат

Химические свойства

Представляет  собой гигроскопическое кристаллическое вещество от белого до  бледно-жёлтого (соломенного) цвета, с сильным запахом хлорида водорода.
Бурно  вступает в реакцию с водой, при этом выделяет большое количество тепла.  Дымится при взаимодействии с влажным воздухом в процессе гидролиза.
Практически  не растворяется в бензоле и толуоле. Имеет хорошую растворимость в  органических растворителях (этиловый спирт, пропанон, 1,2-этандиол,  нитробензен, хлороводород, хлороформ).

Применение

Применяется  в реакциях Фриделя-Крафтса в качестве катализатора (вещество, которое  может быть извлечено в конце реакции, потому что оно только в нем, чтобы  ускорить, замедлить или инициировать реакцию).
Используют как компонент в составе дезодорантов.
Растворы трихлоралюминия применяют при очистке сточных вод и обработке древесины.

хранилище

work with this substance should be conducted in a fume hood, and impermeable gloves should be worn at all times when handling AlCl3. Aluminum chloride should be stored in sealed containers under an inert atmosphere in a cool, dry place. Care should be taken in opening containers of this compound because of the possibility of the buildup of HCl vapor from hydrolysis with traces of moisture.

Безопасность

Вещество достаточно токсичное.
При нагревании в небольших количествах улетучивается.
Способно вызвать раздражение и химические ожоги кожи, глаз и слизистых оболочек.
Попадание на кожу или в глаза в присутствии влаги вызывает термические и кислотные ожоги.
При попадании пыли в организм, вызывает раздражение дыхательных путей.
Реактив вызывает коррозию металлов.
Опасно для водной экосистемы и окружающей среды.
Во время работы с химреактивом необходимо использовать защитные очки, перчатки, закрытую обувь и защитный костюм.

Перевозки

UN1726 Aluminum chloride, anhydrous, Hazard class: 8; Labels: 8-Corrosive material. UN2581 Aluminum chloride solution, Hazard class: 8; Labels: 8-Corrosive material

Методы очистки

Sublime it several times in an all-glass system under nitrogen at 30-50mm pressure. It has also been sublimed in a stream of dry HCl and has been subjected to a preliminary sublimation through a section of granular aluminium metal [for manipulative details see Jensen J Am Chem Soc 79 1226 1957]. It fumes in moist air.

Несовместимости

A strong reducing agent. Contact with air or water forms hydrochloric acid and hydrogen chloride gas. Reaction with water may be violent. Water, alcohol, and alkenes can cause polymerization. Incompatible with nitrobenzene, organic material, and bases. Attacks metal in presence of moisture, forming flammable hydrogen gas.

Утилизация отходов

May be sprayed with aqueous ammonia in the presence of ice and, when reaction is complete, flushed down drain with running water.