Aluminum chloride

White or light-yellow crystalline solid (or amorphous solid depending on the method of production); odor of HCl; hygroscopic; melts at 190°C at 2.5 atm; sublimes at 181.2°C; density 2.44 g/cm3 at 25°C; decomposes in water evolving heat; soluble in HCl; soluble in many organic solvents, including absolute ethanol, chloroform, carbon tetrachloride and ether; slightly soluble in benzene.Aluminum chloride is important industrial chemical. Anhydrous Aluminum chloride is used as the catalyst in variety of Friedel-Crafts type of reactions. Large amounts of ethylbenzene are prepared in this way and are used to make styrene.C6H6 + CH3CH2Cl + AlCl3→C6H5CH2CH3 + H+ + [AlCl4]-Aluminum chloride is also used in the manufacture of anthraquinone (used in dyestuffs industry) and dodecylbenzene (used to make detergents) and in the isomerisation of hydrocarbons (petroleum industry).Aluminum chloride reacts vigorously with water and fumes in air. It is used as a catalyst in cracking petroleum and in organic synthesis.

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.

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 AlCl3molecule 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 Al2Cl6molecules inthe vapour dissociate to (planar)AlCl3molecules. Aluminium chlorideis used commercially as a catalyst inthe cracking of oils. It is also a catalystin certain other organic reactions,especially the Friedel–Craftsreaction.

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

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.

Aluminum chloride has extensive commercial applications. It is used primarily in the electrolytic production of aluminum. Another major use involves its catalytic applications in many organic reactions, including Friedel-Crafts alkylation, polymerization, isomerization, hydrocracking, oxidation, decarboxylation, and dehydrogenation. It is also used in the production of rare earth chlorides, electroplating of aluminum and in many metal finishing and metallurgical operations.

Astringent (topical).

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.

Aluminum chloride is used as a catalyst in many organic reactions.