Misplaced Pages

Sodium perborate

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.

This is an old revision of this page, as edited by Materialscientist (talk | contribs) at 09:03, 1 November 2011 (Reverted edits by 87.163.148.242 (talk) to last version by Rifleman 82). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Revision as of 09:03, 1 November 2011 by Materialscientist (talk | contribs) (Reverted edits by 87.163.148.242 (talk) to last version by Rifleman 82)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)
Sodium perborate
Perborate dimer, peroxide bond shown in red, charges in blue
Names
Other names PBS-1 (mono), PBS-4 (tetra)
Identifiers
CAS Number
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.035.597 Edit this at Wikidata
EC Number
  • 231-556-4
PubChem CID
RTECS number
  • SC7350000
UNII
UN number 1479
InChI
  • InChI=1S/B2H4O8.2Na/c3-1(4)7-9-2(5,6)10-8-1;;/h3-6H;;/q-2;2*+1Key: JBUKJLNBQDQXLI-UHFFFAOYSA-N
  • InChI=1/B2H4O8.2Na/c3-1(4)7-9-2(5,6)10-8-1;;/h3-6H;;/q-2;2*+1Key: JBUKJLNBQDQXLI-UHFFFAOYAG
SMILES
  • ..O1(OO(O)(O)OO1)O
Properties
Chemical formula NaBO3·nH2O
Molar mass 99.815 g/mol (monohydrate);
153.86 g/mol (tetrahydrate)
Appearance white powders
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1 1 0
Flash point non-flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound

Sodium perborate (PBS) is a white, odorless, water-soluble chemical compound with the chemical composition Template:SodiumTemplate:BoronTemplate:Oxygen3. It crystallizes as the monohydrate, NaBO3·H2O, trihydrate, NaBO3·3H2O and tetrahydrate, NaBO3·4H2O. The monohydrate and tetrahydrate are the commercially important forms. The elementary structural unit of sodium perborates is a dimer anion B2O4(OH)4, in which two boron atoms are joined by two peroxo bridges in a chair-shaped 6-membered ring, and the simplistic NaBO3·nH2O-type formulas are just a convenient way to express the average chemical composition.

Preparation and chemistry

Sodium perborate is manufactured by reaction of disodium tetraborate pentahydrate, hydrogen peroxide, and sodium hydroxide. The monohydrate form dissolves better than the tetrahydrate and has higher heat stability; it is prepared by heating the tetrahydrate. Sodium perborate undergoes hydrolysis in contact with water, producing hydrogen peroxide and borate.

Structure

Unlike sodium percarbonate and perphosphate, the sodium perborate is not simply an adduct with hydrogen peroxide, and it does not contain individual and does not contain a BO3 ions. Rather, there is a cyclic dimer anion B2O4(OH)4, in which two boron atoms are joined by two peroxo bridges in a chair-shaped 6-membered ring. This makes the substance more stable, and safer for handling and storage. The formula of the sodium salt is thus Na2H4B2O8.

Uses

It serves as a source of active oxygen in many detergents, laundry detergents, cleaning products, and laundry bleaches. It is also present in some tooth bleaching formulas. It is used as a bleaching agent for internal bleaching of a non vital root treated tooth. The sodium perborate is placed inside the tooth and left in place for an extended period of time to allow it to diffuse into the tooth and bleach stains from the inside out. It has antiseptic properties and can act as a disinfectant. It is also used as a "disappearing" preservative in some brands of eye drops.

Sodium perborate is a less aggressive bleach than sodium hypochlorite, causing less degradation to dyes and textiles. Borates also have some non-oxidative bleaching properties.

Sodium perborate releases oxygen rapidly at temperatures over 60°C. To make it active at lower temperatures (40–60 °C), it has to be mixed with a suitable activator, typically tetraacetylethylenediamine (TAED).

See also

References

  1. ^ B.J Brotherton Boron: Inorganic Chemistry Encyclopedia of Inorganic Chemistry (1994) Ed. R. Bruce King, John Wiley & Sons ISBN 0-471-93620-0
  2. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  3. "Refinement of the X-ray crystal structure of the industrial bleaching agent disodium tetrahydroxo-di-μ-peroxo-diborate hexahydrate, Na2·6H2O". Acta Crystallogr. B34: 3551. 1978. doi:10.1107/S0567740878011565. {{cite journal}}: Unknown parameter |authors= ignored (help)

External links

Stomatological preparations (A01)
Caries prophylaxis
Infection and antiseptics
Corticosteroids
(Glucocorticoids)
Other
Categories: