366. Aluminum Sulfate

Nomenclature

CAS number: 10043-01-3
Sulfuric acid aluminum salt (3:2); aluminum(III) sulfate; Stingose (Pfizer).
Al2O12S3; mol wt 342.15.
Al 15.77%, O 56.11%, S 28.11%.
Al2(SO4)3.

Description and references

Occurs in nature as the mineral alunogenite. Prepn: Gmelins, Aluminum (8th ed.) 35B, pp 267-269 (1934). Soly in aqueous ethanol: A. B. Gancy, C. A. Wamser, J. Chem. Eng. Data 24, 192 (1979). Prepn and characterization of hydrated forms: A. B. Gancy, Thermochim. Acta 54, 105 (1982). Thermal decompn studies: K.-S. Chou, C.-S. Soong, ibid. 78, 285, 305 (1984); Y. Pelovski et al., ibid. 205, 219, 283 (1992). Evaluation as a first-aid treatment for stings and bites: D. Henderson, R. G. Easton, Med. J. Aust. 2, 146 (1980).

Properties

White, lustrous crystals, pieces, granules, or powder. d 1.61. Melts when gradually heated. At 250° loses its water; decomposes at red heat. Sol in 1 part water. Practically insol in alcohol. On long boiling of the aq soln, insol basic salt ppts. The aq soln is acid.

Derivative

Hydrate.

Nomenclature

CAS number: 7784-31-8 (octadecahydrate)
Al2O12S3.18H2O; mol wt 666.43.
Al 8.10%, O 72.02%, S 14.43%, H 5.44%.

Properties

The commercial product is also known as cake alum or patent alum. It is available in degrees of hydration ranging from 14 to 18 molecules of water. Miscible with water.

Use

Tanning leather, sizing paper, mordant in dyeing; purifying water; manuf lakes, aluminum resinate; fireproofing and waterproofing cloth; clarifying oils and fats; treating sewage; waterproofing concrete; deodorizing and decolorizing petroleum; antiperspirants; agricultural pesticides; manuf aluminum salts; prepn of aluminum acetate solns.

Therapeutic Category

Astringent; in treatment of insect and marine organism stings and bites.

Keywords

Astringent