Difference between revisions of "Sodium bromate"
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Sodium bromate is usually prepared by the electrolysis of [[sodium bromide]] solution at 65–70 °C, in the presence of [[dichromate]] and using [[anode]]s of [[lead dioxide]] or [[iron]] and [[cathode]]s of [[stainless steel]] or [[copper]].<ref>{{citation | first1 = Takasi | last1 = Osuga | first2 = Kiichiro | last2 = Sugino | title = Electrolytic Production of Bromates | journal = J. Electrochem. Soc. | volume = 104 | issue = 7 | pages = 448–51 | year = 1957 | doi = 10.1149/1.2428623}}.</ref> The sodium bromate can be crystallized by cooling the electrolyte, and any unoxidized bromide recycled.<ref name="Kirk-Othmer"/> | Sodium bromate is usually prepared by the electrolysis of [[sodium bromide]] solution at 65–70 °C, in the presence of [[dichromate]] and using [[anode]]s of [[lead dioxide]] or [[iron]] and [[cathode]]s of [[stainless steel]] or [[copper]].<ref>{{citation | first1 = Takasi | last1 = Osuga | first2 = Kiichiro | last2 = Sugino | title = Electrolytic Production of Bromates | journal = J. Electrochem. Soc. | volume = 104 | issue = 7 | pages = 448–51 | year = 1957 | doi = 10.1149/1.2428623}}.</ref> The sodium bromate can be crystallized by cooling the electrolyte, and any unoxidized bromide recycled.<ref name="Kirk-Othmer"/> | ||
| − | Sodium bromate can also be prepared by reacting [[bromine]] with [[sodium hydroxide]] solution.<ref>{{citation | inventor1-first = Aavi | inventor1-last = Prager | inventor2-first = Shaul | inventor2-last = Smilovitch | inventor3-first = Mira | inventor3-last = Freiberg | inventor4-first = Haim | inventor4-last = Hariton | assignee = Bromine Compounds Ltd. | title = Alkali and alkaline earth metal bromide and bromate solid mixtures and process for preparation thereof | country-code = IL | patent-number = 84830 | publication date = 1995-01-24}}.</ref> | + | Sodium bromate can also be prepared by reacting [[bromine]] with [[sodium hydroxide]] solution.<ref>{{citation | inventor1-first = Aavi | inventor1-last = Prager | inventor2-first = Shaul | inventor2-last = Smilovitch | inventor3-first = Mira | inventor3-last = Freiberg | inventor4-first = Haim | inventor4-last = Hariton | assignee = Bromine Compounds Ltd. | title = Alkali and alkaline earth metal bromide and bromate solid mixtures and process for preparation thereof | country-code = IL | patent-number = 84830 | publication-date = 1995-01-24}}.</ref> |
:3 Br<sub>2</sub> + 3 OH<sup>−</sup> {{eqm}} BrO{{su|b=3|p=−}} + 5 Br<sup>−</sup> + 3 H<sup>+</sup> | :3 Br<sub>2</sub> + 3 OH<sup>−</sup> {{eqm}} BrO{{su|b=3|p=−}} + 5 Br<sup>−</sup> + 3 H<sup>+</sup> | ||
| − | The disadvantage of this approach is that only one-sixth of the bromine is converted into bromate. However, bromide/bromate mixtures are useful in gold mining, and so this method finds some commercial use. Another approach is to oxidize the remaining bromide with [[chlorine]]:<ref>{{citation | inventor1-first = Naizhi | inventor1-last = Zhao | inventor2-first = Zongsheng | inventor2-last = Wu | inventor3-first = Guishi | inventor3-last = Sun | assignee = Daqinghe Saltern | title = (Method of preparing sodium bromate) | country-code = CN | patent-number = 1102818 | publication-date 1995-05-24}}.</ref> | + | The disadvantage of this approach is that only one-sixth of the bromine is converted into bromate. However, bromide/bromate mixtures are useful in gold mining, and so this method finds some commercial use. Another approach is to oxidize the remaining bromide with [[chlorine]]:<ref>{{citation | inventor1-first = Naizhi | inventor1-last = Zhao | inventor2-first = Zongsheng | inventor2-last = Wu | inventor3-first = Guishi | inventor3-last = Sun | assignee = Daqinghe Saltern | title = 溴酸钠的生产方法 (Method of preparing sodium bromate) | country-code = CN | patent-number = 1102818 | publication-date = 1995-05-24}}.</ref> |
:Br<sub>2</sub> + 2 Cl<sub>2</sub> + 6 OH<sup>−</sup> → 2 BrO{{su|b=3|p=−}} + 4 Cl<sup>−</sup> + 6 H<sup>+</sup> | :Br<sub>2</sub> + 2 Cl<sub>2</sub> + 6 OH<sup>−</sup> → 2 BrO{{su|b=3|p=−}} + 4 Cl<sup>−</sup> + 6 H<sup>+</sup> | ||
Revision as of 08:45, 3 January 2011
| Sodium bromate | |
|---|---|
| IUPAC name | Sodium bromate |
| Other names | Sodium bromate(V) |
| Identifiers | |
| InChI | InChI=1/BrHO3.Na/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 |
| InChIKey | XUXNAKZDHHEHPC-REWHXWOFAY |
| Standard InChI | InChI=1S/BrHO3.Na/c2-1(3)4;/h(H,2,3,4);/q;+1/p-1 |
| Standard InChIKey | XUXNAKZDHHEHPC-UHFFFAOYSA-M |
| CAS number | [] |
| EC number | |
| ChemSpider | |
| Properties[1] | |
| Chemical formula | NaBrO3 |
| Molar mass | 150.89 g mol−1 |
| Appearance | white crystalline solid |
| Density | 3.34 g cm−3 |
| Melting point |
381 °C decomp. |
| Solubility in water | 28.39 g/100 g (25 °C) 43.1 g/100 g (80 °C) |
| Related compounds | |
| Other anions | Sodium chlorate Sodium iodate |
| Other cations | Potassium bromate |
| Other compounds | Sodium bromide Sodium hypobromite Sodium bromite Sodium perbromate |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
Sodium bromate is the sodium salt of bromic acid. It is used as a neutralizer-oxidizer in hair-wave preparations and in textile bleaching.[1]
Preparation
Sodium bromate is usually prepared by the electrolysis of sodium bromide solution at 65–70 °C, in the presence of dichromate and using anodes of lead dioxide or iron and cathodes of stainless steel or copper.[2] The sodium bromate can be crystallized by cooling the electrolyte, and any unoxidized bromide recycled.[1]
Sodium bromate can also be prepared by reacting bromine with sodium hydroxide solution.[3]
- 3 Br2 + 3 OH− ⇌ BrO−3 + 5 Br− + 3 H+
The disadvantage of this approach is that only one-sixth of the bromine is converted into bromate. However, bromide/bromate mixtures are useful in gold mining, and so this method finds some commercial use. Another approach is to oxidize the remaining bromide with chlorine:[4]
- Br2 + 2 Cl2 + 6 OH− → 2 BrO−3 + 4 Cl− + 6 H+
Notes and references
Notes
References
- ↑ 1.0 1.1 1.2 Ukeles, S. D.; Freiberg, M. Bromine, Inorganic Compounds. In Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley: New York, 2002. DOI: 10.1002/0471238961.021815131001031.
- ↑ Osuga, Takasi; Sugino, Kiichiro Electrolytic Production of Bromates. J. Electrochem. Soc. 1957, 104 (7), 448–51. DOI: 10.1149/1.2428623.
- ↑ Prager, Aavi; Smilovitch, Shaul; Freiberg, Mira, et al. (Bromine Compounds Ltd.) Alkali and alkaline earth metal bromide and bromate solid mixtures and process for preparation thereof. IL Patent 84830, published 24 January 1995.
- ↑ Zhao, Naizhi; Wu, Zongsheng; Sun, Guishi (Daqinghe Saltern) 溴酸钠的生产方法 (Method of preparing sodium bromate). CN Patent 1102818, published 24 May 1995.
External links
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See also the corresponding article on Wikipedia. |
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