Ammonium persulfate

Ammonium persulfate (APS) is the inorganic compound with the formula (NH4)2S2O8. It is a colourless (white) salt that is highly soluble in water, much more so than the related potassium salt. It is a strong oxidizing agent that is used in polymer chemistry, as an etchant, and as a cleaning and bleaching agent.

Ammonium persulfate
Names
Other names
Ammonium peroxydisulfate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.028.897
EC Number
  • 231-786-5
E number E923 (glazing agents, ...)
RTECS number
  • SE0350000
UNII
UN number 1444
Properties
(NH4)2S2O8
Molar mass 228.18 g/mol
Appearance white to yellowish crystals
Density 1.98 g/cm3
Melting point 120 °C (248 °F; 393 K) decomposes
80 g/100 mL (25 °C)
Solubility Moderately soluble in MeOH
Hazards
Safety data sheet 7727-54-0
GHS pictograms
GHS Signal word Danger
GHS hazard statements
 H272, H302, H315, H319, H334, H317, H335
P210, P221, P284, P305+351+338, P405, P501
NFPA 704 (fire diamond)
Airborne: 0.1 mg/m³ (TWA)
Lethal dose or concentration (LD, LC):
689 mg/kg (rat, oral);
2,000 mg/kg (rat, dermal);
2.95 mg/L for 4 hours (rat, inhalation)
Related compounds
Other anions
 Ammonium thiosulfate
Ammonium sulfite
Ammonium sulfate
Other cations
 Sodium persulfate
Potassium persulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

The dissolution of the salt in water is an endothermic process.

Preparation

Ammonium persulfate is prepared by electrolysis of a cold concentrated solution of either ammonium sulfate or ammonium bisulfate in sulfuric acid at a high current density.[1][2] The method was first described by Hugh Marshall.[3]

Uses

As an oxidizing agent and a source of radicals, APS finds many commercial applications.

Salts of sulfate are mainly used as radical initiators in the polymerization of certain alkenes. Commercially important polymers prepared using persulfates include styrene-butadiene rubber and polytetrafluoroethylene. In solution, the dianion dissociates to give radicals:[4]

[O3SO–OSO3]2− ⇌ 2 [SO4]•−

The sulfate radical adds to the alkene to give a sulfate ester radical. It is also used along with tetramethylethylenediamine to catalyze the polymerization of acrylamide in making a polyacrylamide gel, hence being important for SDS-PAGE and western blot.

Illustrative of its powerful oxidizing properties, it is used to etch copper on printed circuit boards as an alternative to ferric chloride solution.[5] This property was discovered many years ago. In 1908, John William Turrentine used a dilute ammonium persulfate solution to etch copper. Turrentine weighed copper spirals before placing the copper spirals into the ammonium persulfate solution for an hour. After an hour, the spirals were weighed again and the amount of copper dissolved by ammonium persulfate was recorded. This experiment was extended to other metals such as nickel, cadmium, and iron, all of which yielded similar results.[6] The oxidation equation is thus: S
2O2−
8 (aq) +  e− → 2 SO2−
4 (aq).

Ammonium persulfate is a standard ingredient in hair bleach.

Persulfates are used as oxidants in organic chemistry.[7] For example, in the Minisci reaction.

Safety

Airborne dust containing ammonium persulfate may be irritating to eye, nose, throat, lung and skin upon contact. Exposure to high levels of dust may cause difficulty in breathing.[8]

It has been noted that persulfate salts are a major cause of asthmatic effects in women.[9] Furthermore, it has been suggested that exposure to ammonium persulfate can cause asthmatic effects in hair dressers and receptionists working in the hairdressing industry. These asthmatic effects are proposed to be caused by the oxidation of cysteine residues, as well as methionine residues.[10]

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gollark: But nowhere else.
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gollark: This seems very poorly designed but I can't (be bothered to) work out enough of its structure to say.
gollark: It's nim's vector type.

References
  1. Shafiee, Saiful Arifin; Aarons, Jolyon; Hamzah, Hairul Hisham (2018). "Electroreduction of Peroxodisulfate: A Review of a Complicated Reaction". Journal of the Electrochemical Society. 165 (13): H785–H798. doi:10.1149/2.1161811jes.
  2. F. Feher, "Potassium Peroxydisulfate" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 390.
  3. Hugh Marshall (1891). "LXXIV. Contributions from the Chemical Laboratory of the University of Edinburgh. No. V. The trisulphates". J. Chem. Soc., Trans. 59: 771–786. doi:10.1039/CT8915900771.
  4. Harald Jakob; Stefan Leininger; Thomas Lehmann; Sylvia Jacobi; Sven Gutewort. "Peroxo Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_177.pub2.
  5. "Ammonium Persulphate: Copper Etchant". MG Chemicals.
  6. Turrentine, J. W. (1908). "Action of Ammonium Persulphate on Metals". Journal of Physical Chemistry. 11 (8): 623–631. doi:10.1021/j150089a004.
  7. Encyclopedia of Reagents for Organic Synthesis, vol. 1, pp. 193–197 (1995).
  8. "Archived copy" (PDF). Archived from the original (PDF) on 2011-07-11. Retrieved 2010-03-08.CS1 maint: archived copy as title (link) FMC Corporation, MSDS sheet dated: 2009-06-26
  9. De Vooght, V.; Jesus Cruz, M.; Haenen, S.; Wijnhoven, K.; Munoz, X.; Cruz, M.; Munoz, X.; Morell, F.; Nemery, B (2010). "Ammonium persulfate can initiate an asthmatic response in mice". Thorax. 65 (3): 252–257. doi:10.1136/thx.2009.121293. PMID 20335296.
  10. Pignatti, P.; Frossi, B.; Pala, G.; Negri, S.; Oman, H.; Perfetti, L.; Pucillo, C.; Imbriani, M.; Moscato, G. (2013). "Oxidative activity of ammonium persulfate salt on mast cells and basophils: implication in hairdressers' asthma". Int. Arch. Allergy Immunol. 160 (4): 409–419. doi:10.1159/000343020. PMID 23183487.
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