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.
3D model (JSmol)
|E number||E923 (glazing agents, ...)|
CompTox Dashboard (EPA)
|Molar mass||228.18 g/mol|
|Appearance||white to yellowish crystals|
|Melting point||120 °C (248 °F; 393 K) decomposes|
|80 g/100 mL (25 °C)|
|Solubility||Moderately soluble in MeOH|
|Safety data sheet||7727-54-0|
|GHS Signal word||Danger|
|H272, H302, H315, H319, H334, H317, H335|
|P210, P221, P284, P305+351+338, P405, P501|
|NFPA 704 (fire diamond)|
Threshold limit value (TLV)
|Airborne: 0.1 mg/m³ (TWA)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|689 mg/kg (rat, oral);|
2,000 mg/kg (rat, dermal);
2.95 mg/L for 4 hours (rat, inhalation)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
The dissolution of the salt in water is an endothermic process.
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. The method was first described by Hugh Marshall.
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:
- [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. 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.
The oxidation equation is thus: S
8 (aq) + e− → 2 SO2−
Ammonium persulfate is a standard ingredient in hair bleach.
It has been noted that persulfate salts are a major cause of asthmatic effects in women. 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.
- 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.
- F. Feher, "Potassium Peroxydisulfate" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 390.
- 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.
- 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.
- "Ammonium Persulphate: Copper Etchant". MG Chemicals.
- Turrentine, J. W. (1908). "Action of Ammonium Persulphate on Metals". Journal of Physical Chemistry. 11 (8): 623–631. doi:10.1021/j150089a004.
- Encyclopedia of Reagents for Organic Synthesis, vol. 1, pp. 193–197 (1995).
- "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
- 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.
- 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.