“Potassium persulfate”的意思、由来-开放百科全书

词条

Potassium persulfate

释义

Preparation
Uses
Precautions
References

{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 441025344
| Name = Potassium persulfate
| ImageFile = Potassium persulfate.png
| ImageName = Two potassium cations and one peroxydisulfate anion
| ImageFile1 = Potassium-persulfate-xtal-1997-3D-balls.png
| ImageName1 = Ball-and-stick model of the crystal structure
| ImageFile2 = Peroxodisíran draselný.JPG
| ImageName2 = Potassium persulfate as a white powder
| OtherNames = potassium peroxydisulfate
Anthion
potassium perdisulfate
|Section1={{Chembox Identifiers
| CASNo = 7727-21-1
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 24412
| EINECS = 231-781-8
| UNNumber = 1492
| RTECS = SE0400000
| SMILES = [O-]S(=O)(=O)OOS(=O)(=O)[O-].[K+].[K+]
| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}
| ChemSpiderID = 22821
| InChI = 1/2K.H2O8S2/c;;1-9(2,3)7-8-10(4,5)6/h;;(H,1,2,3)(H,4,5,6)/q2*+1;/p-2
| InChIKey = USHAGKDGDHPEEY-NUQVWONBAA
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/2K.H2O8S2/c;;1-9(2,3)7-8-10(4,5)6/h;;(H,1,2,3)(H,4,5,6)/q2*+1;/p-2
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = USHAGKDGDHPEEY-UHFFFAOYSA-L
|Section2={{Chembox Properties
| Formula = K₂S₂O₈
| MolarMass = 270.322 g/mol
| Appearance = white powder
| Odor = odorless
| Density = 2.477 g/cm³^[1]
| Solubility = 1.75 g/100 mL (0 °C)
4.49 g/100 ml (20 °C)
| SolubleOther = insoluble in alcohol
| MeltingPt= <
| MeltingPtC = 100
| MeltingPt_notes = (decomposes)
| RefractIndex = 1.467
|Section3={{Chembox Structure
| CrystalStruct = triclinic
|Section7={{Chembox Hazards
| ExternalSDS = ICSC 1133
| GHSPictograms = {{GHS03}} {{GHS07}} {{GHS08}}
| GHSSignalWord = DANGER
| HPhrases = {{H-phrases|272|302|315|317|319|334|335|371}}
| PPhrases = {{P-phrases|220|261|280|305+351+338|342+311}}
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 1
| NFPA-S = OX
| FlashPt = Non-flammable
| PEL =
| LD50 = 802 mg/kg (oral, rat)^[1]
|Section8={{Chembox Related
| OtherAnions = Potassium sulfite
Potassium sulfate
Potassium peroxymonosulfate
| OtherCations = Sodium persulfate
| OtherFunction =
| OtherFunction_label =
| OtherCompounds =
}}

Not to be confused with potassium peroxymonosulfate.

Potassium persulfate is the inorganic compound with the formula K₂S₂O₈. Also known as potassium peroxydisulfate or KPS, it is a white solid that is sparingly soluble in cold water, but dissolves better in warm water. This salt is a powerful oxidant, commonly used to initiate polymerizations.

Preparation

Potassium persulfate can be prepared by electrolysis of a cold solution potassium bisulfate in sulfuric acid at a high current density.^[2]

2 KHSO₄ → K₂S₂O₈ + H₂

It can also be prepared by adding potassium bisulfate (KHSO₄) to a solution of the more soluble salt ammonium peroxydisulfate (NH₄)₂S₂O₈. In principle it can be prepared by chemical oxidation of potassium sulfate using fluorine.

Uses

This salt is used to initiate polymeriziation of various alkenes leading to commercially important polymers such as styrene-butadiene rubber and polytetrafluoroethylene and related materials. In solution, the dianion dissociates to give radicals:^[3]

[O₃SO-OSO₃]²⁻ {{eqm}} 2 [SO₄]⁻

It is used in organic chemistry as an oxidizing agent,^[4] for instance in the Elbs persulfate oxidation of phenols and the Boyland–Sims oxidation of anilines.

As a strong yet stable bleaching agent it also finds use in various hair bleaches and lighteners. Such brief and non-continuous use is normally hazard free, however prolonged contact can cause skin irritation.^[5]

It has been used as an improving agent for flour with the E number E922, although it is no longer approved for this use within the EU.

Precautions

The salt is a strong oxidant and is incompatible with organic compounds. Prolonged skin contact can result in irritation.^[5]

References

1. ^http://chem.sis.nlm.nih.gov/chemidplus/rn/7727-21-1
2. ^¹{{cite book|last=Brauer|first=Georg|title=Handbook of Preparative Inorganic Chemistry |volume=1 |edition=2nd |year=1963 |publisher=Academic Press |location=New York |isbn=978-0121266011 |page=392 |url=https://books.google.com/books?id=TLYatwAACAAJ&dq=Handbook+of+Preparative+Inorganic+Chemistry&hl=en&sa=X&ei=IPT2UtTZGMfgoASR1IGgDg&ved=0CC8Q6AEwAQ}}
3. ^{{Ullmann | title = Peroxo Compounds, Inorganic |author=Harald Jakob |author2=Stefan Leininger |author3=Thomas Lehmann |author4=Sylvia Jacobi |author5=Sven Gutewort | doi = 10.1002/14356007.a19_177.pub2}}
4. ^Encyclopedia of Reagents for Organic Synthesis, vol. 1, pp. 193–197(1995)
5. ^¹{{cite journal|title=Final Report on the Safety Assessment of Ammonium, Potassium, and Sodium Persulfate|journal=International Journal of Toxicology|date=January 2001|volume=20|issue=3|page=7-21|doi=10.1080/10915810152630710}}

4 : Persulfates|Potassium compounds|Oxidizing agents|Radical initiators

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