|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)|
|EU classification||Oxidant (O)
|R-phrases||R8, R22, R36/37/38, R42/43|
|S-phrases||(S2), S22, S24, S26, S37|
LD50 (Median lethal dose)
|689 mg/kg, oral (rat)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is: / ?)(|
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.
The dissolution of the salt in water is an endothermic process.
Salts of peroxydisulfate 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.
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: 1/2 S2O8 (aq)2− + e− -> SO4 (aq)2−.
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 hair dressing industry. These asthmatic effects are proposed to be caused by the oxidation of cysteine residues, as well as methionine residues.
- 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 persulphates". J. Chem. Soc., Trans. 59: 771. doi:10.1039/CT8915900771.
- 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
- "Ammonium Persulphate: Copper Etchant". MG Chemicals.
- Turrentine, J. W. (1908). "Action of Ammonium Persulphate on Metals.". Journal of Physical Chemistry 11: 623–631. doi:10.1021/j150089a004.
- Encyclopedia of Reagents for Organic Synthesis, vol. 1, pp. 193–197 (1995).
-  FMC Corporation, MSDS sheet dated: 06/26/2009
- 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: 252–257. doi:10.1136/thx.2009.121293.
- 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: 409–419. doi:10.1159/000343020.