| Revision as of 12:17, 15 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 476523071 of page Sodium_sulfite for the Chem/Drugbox validation project (updated: ''). |
Latest revision as of 14:55, 12 August 2024 edit Utopes (talk | contribs)Extended confirmed users, Page movers, IP block exemptions, New page reviewers, Pending changes reviewers, Rollbackers38,741 edits →References: sulfites |
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{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}} |
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{{chembox |
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{{chembox |
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| verifiedrevid = 464362863 |
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| verifiedrevid = 476993033 |
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| Name = Sodium sulfite |
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| Name = Sodium sulphite |
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| ImageFile = Na2SO3.svg |
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| ImageFile1 = sodium sulfite.png |
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| ImageName1 = Sodium sulfite |
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| ImageName = Sodium sulfite |
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| ImageFileL2 = Sodium sulfite.jpg |
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| ImageFileL1 = Sodium sulfite.jpg |
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| ImageCaptionL2 = anhydrous |
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| ImageCaptionL1 = anhydrous |
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| ImageFileR2 = Sodium sulfite hydrate.jpg |
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| ImageFileR1 = Sodium sulfite hydrate.jpg |
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| ImageCaptionR2 = hydrate |
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| ImageCaptionR1 = hydrate |
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| IUPACName = Sodium sulfite |
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| IUPACName = Sodium sulfite |
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| OtherNames = Hypo clear (photography)<br>E221 |
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| OtherNames = {{Unbulleted list|Hypo clear (photography)|E221}} |
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| Section1 = {{Chembox Identifiers |
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|Section1={{Chembox Identifiers |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID = 22845 |
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| ChemSpiderID = 22845 |
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| ChEBI_Ref = {{ebicite|changed|EBI}} |
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| ChEBI = 86477 |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII = VTK01UQK3G |
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| UNII = VTK01UQK3G |
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| PubChem = 24437 |
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| PubChem = 24437 |
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| RTECS = WE2150000 |
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| RTECS = WE2150000 |
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| EINECS = 231-821-4 |
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| Section2 = {{Chembox Properties |
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|Section2={{Chembox Properties |
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| Formula = Na<sub>2</sub>SO<sub>3</sub> |
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| Formula = Na<sub>2</sub>SO<sub>3</sub> |
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| MolarMass = 126.043 g/mol |
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| MolarMass = 126.043{{nbsp}}g/mol |
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| Appearance = white solid |
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| Appearance = White solid |
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| Odor = Odorless |
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| Density = 2.633 g/cm<sup>3</sup> (anhydrous)<br/>1.561 g/cm<sup>3</sup> (heptahydrate) |
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| Solubility = 678 g/L (18 °C, heptahydrate) |
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| Density = 2.633{{nbsp}}g/cm<sup>3</sup> (anhydrous)<br/>1.561{{nbsp}}g/cm<sup>3</sup> (heptahydrate) |
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| Solubility = 27.0{{nbsp}}g/100{{thinsp}}mL water (20{{nbsp}}°C) |
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| MeltingPt = 33.4 °C (dehydration of heptahydrate)<br/> 500 °C (anhydrous) |
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| SolubleOther = Soluble in ] <br>Insoluble in ], ] |
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| BoilingPt = Decomposes(separate (substances) into constituent elements) |
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| MeltingPtC = 33.4 |
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| MeltingPt_notes = (dehydration of heptahydrate)<br/> 500 °C (anhydrous) |
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| Section3 = {{Chembox Structure |
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| BoilingPt = Decomposes |
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| RefractIndex = 1.565 |
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| pKa = ~9 (heptahydrate) |
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| LogP = −4 |
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|Section3={{Chembox Structure |
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| MolShape = |
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| Coordination = |
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| Coordination = |
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| CrystalStruct = hexagonal (anhydrous)<br/>monoclinic (heptahydrate) |
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| CrystalStruct = Hexagonal (anhydrous)<br/>Monoclinic (heptahydrate) |
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| Dipole = |
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| Section7 = {{Chembox Hazards |
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|Section7={{Chembox Hazards |
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| ExternalMSDS = |
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| ExternalSDS = |
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| EUIndex = Not listed |
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| MainHazards = |
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| MainHazards = |
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| FlashPt = Non-flammable |
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| FlashPt = Non-flammable |
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| HPhrases = |
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| SPhrases = |
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| PPhrases = |
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| GHS_ref = |
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| NFPA-H = 2 |
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| NFPA-H = 2 |
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| NFPA-F = 0 |
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| NFPA-F = 0 |
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| NFPA-R = 0 |
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| NFPA-R = 0 |
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| Section8 = {{Chembox Related |
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| OtherAnions = ] |
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| OtherAnions = ] |
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| OtherCations = ] |
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| OtherCations = ] |
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| OtherCpds = ]<br/>]<br/>] |
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| OtherCompounds = ]<br/>]<br/>] |
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'''Sodium sulfite''' ('''sodium sulphite''') is the ] with the ] ]]. A white, water-soluble solid, it is used commercially as an antioxidant and preservative. It is also suitable for the softening of ] in the pulping and refining processes of ] and ].<ref>{{cite web| title= High Yield Pulp Production by Modified Sulfite Process| url=https://ippta.co/wp-content/uploads/2021/01/IPPTA-VII1-39-42-High-Yield-Pulp-Production.pdf | access-date=2023-10-19}}</ref> A heptahydrate is also known but it is less useful because of its greater susceptibility toward oxidation by air.<ref name=IS/> |
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==Preparation== |
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] |
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Sodium sulfite can be prepared by treating a solution of ] with ]. When conducted in warm water, Na<sub>2</sub>SO<sub>3</sub> initially precipitates as a white solid. With more SO<sub>2</sub>, the solid dissolves to give the ], which crystallizes upon cooling.<ref name=IS>{{cite book|doi=10.1002/9780470132333.ch49|isbn=9780470132333|chapter=Sulfites and Pyrosulfites of the Alkali Metals|year=1946|last1=Johnstone|first1=H. F.|title=Inorganic Syntheses|pages=162–167|volume=2}}</ref> |
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:<chem>SO2 + 2 NaOH -> Na2SO3 + H2O</chem> |
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Sodium sulfite is made industrially by treating sulfur dioxide with a solution of sodium carbonate.<ref Name="Kirk-Othmer">{{cite book |last1=Weil |first1=Edward D. |last2=Sandler |first2=Stanley R. |editor1-first= Jacqueline I. |editor1-last= Kroschwitz |title=Kirk-Othmer Concise Encyclopedia of Chemical Technology |edition=4th |year=1999 |publisher= John Wiley & Sons, Inc.|location=New York|isbn=978-0471419617|page=1937 |chapter=Sulfur Compounds}}</ref> The overall reaction is: |
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:<chem>SO2 + Na2CO3 -> Na2SO3 + CO2</chem> |
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==Uses== |
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Sodium sulfite is primarily used in the ].<ref>{{Ullmann|doi=10.1002/14356007.a25_477|isbn=3527306730|title=Sulfites, Thiosulfates, and Dithionitesl Chemistry|year=2000|last1=Barberá|first1=José Jiménez|last2=Metzger|first2=Adolf|last3=Wolf|first3=Manfred}}</ref> It has been also applied in the thermomechanical conversion of wood to fibres (''defibration'') for producing medium density fibreboards (MDF).<ref>{{cite web | title=DE19958756A1 - Production of light-colored medium-density fibreboard (MDF) from old fibreboard comprises treatment with sodium sulfite, conversion into pulp and feeding into the blow-line of an MDF plant | website=Google Patents | date=1999-12-07 | url=https://patents.google.com/patent/DE19958756A1/en | access-date=2022-03-01}}</ref> |
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As an oxygen scavenger agent, it is used to treat water being fed to steam boilers to avoid corrosion problems,<ref>{{cite web | url=http://www.gewater.com/handbook/boiler_water_systems/ch_11_preboiler.jsp | title=Pre-boiler and Boiler Corrosion Control | GE Water | access-date=2016-03-14 | archive-date=2017-10-06 | archive-url=https://web.archive.org/web/20171006062229/https://www.gewater.com/handbook/boiler_water_systems/ch_11_preboiler.jsp | url-status=dead }}</ref> in the photographic industry, it protects developer solutions from oxidation and (as hypo clear solution) to wash fixer (]) from film and photo-paper emulsions. |
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As a reducing agent it is used in the textile industry as a bleaching, desulfurizing, and dechlorinating agent (e.g. in swimming pools). Its reducing properties are exploited in its use as a ] to prevent ] from discoloring, and for preserving meats. |
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It is used as a reagent in sulfonation and sulfomethylation agent. It is used in the production of ]. |
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The ] utilizes sodium sulfite for ]. |
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==Reactions== |
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{{main|sulfite}} |
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Sodium sulfite is primarily used as a mild reducing agent. The heptahydrate crystals ] in warm dry air. Heptahydrate crystals also oxidize in air to form sodium sulfate. The anhydrous form is more resistant to oxidation by air.<ref name="merck">Merck Index of Chemicals and Drugs, 9th ed. monograph 8451</ref> |
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], NaHSO<sub>3</sub>, is mixture of salts that dissolve in water to give solutions composed of sodium and bisulfite ions. |
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==Structure== |
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According to ] sodium sulfite heptahydrate features pyramidal SO<sub>3</sub><sup>2-</sup> centers. The S-O distances are 1.50 and the O-S-O angles are near 106º.<ref>{{cite journal |doi=10.3891/acta.chem.scand.23-2253|title=The Crystal Structure of Sodium Sulphite. A Refinement Allowing for the Effect of Crystal Twinning|year=1969|last1=Larsson|first1=Lars Olof|last2=Kierkegaard|first2=Peder|last3=Lindberg|first3=Bengt|last4=Holme|first4=Tord|last5=Lindberg|first5=Alf A.|last6=Craig|first6=J. Cymerman|journal=Acta Chemica Scandinavica|volume=23|pages=2253–2260|doi-access=free}}</ref> |
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==References== |
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{{reflist}} |
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{{Sodium compounds}} |
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{{Sulfites}} |
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] |
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] |
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] |