Sodium persulfate

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Sodium persulfate
Two sodium cations and one peroxodisulphate anion
Ball-and-stick model of the crystal structure
Sodium persulfate as a white powder
Identifiers
CAS number 7775-27-1 YesY
PubChem 62655
ChemSpider 56406 YesY
EC number 231-892-1
UN number 1505
ChEMBL CHEMBL502764 YesY
RTECS number SE0525000
Jmol-3D images Image 1
Properties
Molecular formula Na2S2O8
Molar mass 238.10 g/mol
Appearance white powder
Density 2.59 g/cm3
(Loose bulk density: 1.12 g/cm3)[1]
Melting point 180 °C (356 °F; 453 K) decomposes
Solubility in water 55.6 g/100 ml (20 °C)
Hazards
MSDS ICSC 1136
EU Index Not listed
R-phrases R8 R20 R22 R36 R37 R38
S-phrases S17 S26 S36
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazard OX: Oxidizer. E.g., potassium perchlorateNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions Sodium dithionite
Sodium sulfite
Sodium sulfate
Other cations Potassium persulfate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Sodium persulfate is the inorganic compound with the formula Na2S2O8. It is the sodium salt of persulfate (also called peroxydisulate), an oxidizer. It is a white solid that dissolves in water. It is almost non-hygroscopic and has good shelf-life.

Production[edit]

The salt is prepared by the electrolytic oxidation of sodium hydrogen sulfate:

2 NaHSO4 → Na2S2O8 + H2

Oxidation is conducted at a platinum anode.[2] In this way about 165,000 tons were produced in 2005.[3]

The standard redox potential of sodium persulfate into hydrogen sulfate is 2.1 V, which is higher than that of hydrogen peroxide (1.8 V) but lower than ozone (2.2 V).[4] The sulfate radical formed in situ has a standard electrode potential of 2.7 V.

Applications[edit]

It is mainly used as a radical initiator for emulsion polymerization reactions for styrene based polymers such as Acrylonitrile butadiene styrene.[3] Also applicable for accelerated curing of low formaldehyde adhesives.

Other uses[edit]

It is a bleach, both standalone (particularly in hair cosmetics) and as a detergent component. It is a replacement for ammonium persulfate in etching mixtures for zinc and printed circuit boards, and is used for pickling of copper and some other metals.

It is also used as a soil conditioner and soil remediation and in manufacture of dyestuffs, modification of starch, bleach activator, desizing agent for oxidative desizing, etc.

Organic chemistry[edit]

Sodium persulfate is a specialized oxidizing agent in chemistry, for example in a synthesis of diapocynin from apocynin where iron(II) sulfate is the radical initiator:[5]

Diapocynin Synthesis

Safety[edit]

The salt is an oxidizer and forms combustable mixtures with organic materials such as paper.

References[edit]

  1. ^ FMC Corporation. Sodium Persulfate. http://www.fmcchemicals.com/Portals/chem/Content/docs/Tech%20Data%20Sheets/sodpersulfate.pdf (accessed Nov 17, 2013).
  2. ^ Pietzsch, A.; Adolph, G. J. Chem. Technol. Biotechnol. 1911, 30, 85.
  3. ^ a b Harald Jakob, Stefan Leininger, Thomas Lehmann, Sylvia Jacobi, Sven Gutewort (2005), "Peroxo Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a19_177.pub2 
  4. ^ Block, Philip A., Richard A. Brown, and David Robinson. "Novel activation technologies for sodium persulfate in situ chemical oxidation." Proceedings of the Fourth International Conference on the remediation of chlorinated and recalcitrant compounds. 2004.
  5. ^ Luchtefeld, Ron; Dasari, Mina S.; Richards, Kristy M.; Alt, Mikaela L.; Crawford, Clark F. P.; Schleiden, Amanda; Ingram, Jai; Hamidou, Abdel Aziz Amadou et al. (2008). "Synthesis of Diapocynin". J. Chem. Ed. 85 (3): 411. doi:10.1021/ed085p411.