Sodium aluminosilicate

Sodium aluminosilicate refers to compounds which contain sodium, aluminium, silicon and oxygen, and which may also contain water. These include synthetic amorphous sodium aluminosilicate, a few naturally occurring minerals and synthetic zeolites. Synthetic amorphous sodium aluminosilicate is widely used as a food additive, E 554.

Sodium aluminosilicate
Names
IUPAC name
aluminum sodium dioxido(oxo)silane
Other names
Aluminosilicic acid, aluminum sodium silicate
Identifiers
3D model (JSmol)
ECHA InfoCard 100.014.259
E number E554 (acidity regulators, ...)
UNII
  • InChI=1S/Al.Na.2O3Si/c;;2*1-4(2)3/q+3;+1;2*-2 checkY
    Key: URGAHOPLAPQHLN-UHFFFAOYSA-N checkY
  • [O-] [Si](=O)[O-].[O-] [Si](=O)[O-].[Na+].[Al+3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Amorphous sodium aluminosilicate

This substance is produced with a wide range of compositions and has many different applications. It is encountered as an additive E 554 in food where it acts as an anticaking (free flow) agent. As it is manufactured with a range of compositions it is not strictly a chemical compound with a fixed stoichiometry.[1] One supplier quotes a typical analysis for one of their products as 14SiO2·Al2O3·Na2O·3H2O,(Na2Al2Si14O32·3H2O).[2]

The US FDA has as of April 1, 2012 approved sodium aluminosilicate (sodium silicoaluminate) for direct contact with consumable items under 21 CFR 182.2727.[3] Sodium aluminosilicate is used as molecular sieve in medicinal containers to keep contents dry.

Sodium aluminosilicate may also be listed as:

  • aluminium sodium salt
  • sodium silicoaluminate
  • aluminosilicic acid, sodium salt
  • sodium aluminium silicate
  • aluminum sodium silicate
  • sodium silico aluminate
  • sasil

As a problem in industrial processes

The formation of sodium aluminosilicate makes the Bayer process uneconomical for bauxites high in silica.

Minerals sometimes called sodium aluminosilicate

Naturally occurring minerals that are sometimes given the chemical name, sodium aluminosilicate include albite (NaAlSi3O8, an end-member of the plagioclase series) and jadeite (NaAlSi2O6).

Synthetic zeolites sometimes called sodium aluminosilicate

Synthetic zeolites have complex structures and examples (with structural formulae) are:

  • Na12Al12Si12O48·27H2O, zeolite A (Linde type A sodium form, NaA), used in laundry detergents[4]
  • Na16Al16Si32O96·16H2O, Analcime, IUPAC code ANA[4]
  • Na12Al12Si12O48·q H2O, Losod[5]
  • Na384Al384Si384O1536·518H2O, Linde type N

References
  1. United Nations Environment Programme Archived 2010-03-31 at the Wayback Machine
  2. Solvay link no longer works
  3. "Sec. 182.2727 Sodium aluminosilicate". U.S. Food and Drug Administration. 1 April 2012. Retrieved 10 December 2012.
  4. Alan Dyer, (1994),Encyclopedia of Inorganic Chemistry, ed R. Bruce King, John Wiley & Sons, ISBN 0-471-93620-0
  5. "Formation and Properties of Losod, a New Sodium Zeolite", Werner Sieber, Walter M. Meie Helvetica Chimica Acta, Volume 57 Issue 6, pp. 1533–1549, 10.1002/hlca.19740570608
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