Sodium perborate
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| Sodium perborate | |
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| Other names | PBS-1 (mono), PBS-4 (tetra) |
| Identifiers | |
| CAS number | [7632-04-4 (monohydrate), 10486-00-7(tetrahydrate)] |
| Properties | |
| Molecular formula | NaBO3.nH2O |
| Molar mass | 99.8151 g/mol (mono); 153.8611 g/mol (tetra) |
| Appearance | white powders |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Sodium perborate (PBS) is a white, odorless, water-soluble chemical compound with chemical formula NaBO3. It crystallizes as the monohydrate, NaBO3.H2O, tetrahydrate, NaBO3.4H2O and trihydrate, NaBO3.3H2 O. [1]The monohydrate and tetrahydrate are the commercially important forms.[1]
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[edit] Preparation and chemistry
Sodium perborate is manufactured by reaction of disodium tetraborate pentahydrate, hydrogen peroxide, and sodium hydroxide.[1]The monohydrate form dissolves better than the tetrahydrate and has higher heat stability; it is prepared by heating the tetrahydrate.[1] Sodium perborate undergoes hydrolysis in contact with water, producing hydrogen peroxide and borate.[1]
[edit] Structure
Unlike sodium percarbonate and perphosphate, the sodium perborate are not simply addition compounds of hydrogen peroxide, but contain a cyclic anion with peroxo bridges and do not contain the BO3− ion. [2]. This makes the material more stable, safer for handling and storage. The formulae of the mono and tetra hydrates can therefore be written as Na2B2O8H4 (anhydrous) and Na2B2O8H4.6H2O respectively.[1]
[edit] Uses
It serves as a source of active oxygen in many detergents, laundry detergents, cleaning products, and laundry bleaches.[1] It is also present in some tooth bleaching formulas. 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).
[edit] Hazards
It is a skin irritant.
[edit] See also
- Amosan
- Sodium percarbonate
- Sodium perphosphate
- Persil
[edit] References
- ^ a b c d e f g B.J Brotherton Boron: Inorganic Chemistry Encyclopedia of Inorganic Chemistry (1994) Ed. R. Bruce King, John Wiley & Sons ISBN 0471936200
- ^ Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
[edit] External links
- Borax Detergent Book: Bleaching
- National Pollutant Inventory - Boron and compounds
- Sodium perborate history, image
- Sodium perborate in organic synthesis
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