Peroxymonosulfuric acid
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| Peroxymonosulfuric acid | |
|---|---|
| Image:Peroxymonosulfuric acid.svg | |
| General | |
| Systematic name | Peroxysulfuric acid |
| Other names | persulfuric acid; |
| Molecular formula | H2SO5 |
| Molar mass | 114.04 g/mol |
| Appearance | white solid |
| CAS number | 7722-86-3 |
| Properties | |
| Density and phase | ??? g/cm3, solid |
| Solubility in water | soluble |
| in methanol | soluble |
| Melting point | 45 °C |
| Boiling point | decomposes |
| Structure | |
| Coordination geometry | tetrahedral |
| Crystal structure | ?? |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | strong oxidizer |
| NFPA 704 |   
|
| Flash point | n/a |
| R/S statement | ?? |
| RTECS number | ?? |
| Supplementary data page | |
| Structure & properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid |
| Spectral data | UV, IR, NMR, MS |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references | |
Peroxymonosulfuric acid, also known as persulfuric acid and as Caro's acid, is H2SO5, a colorless solid melting at 45 °C. In this acid, the S(VI) center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO-O-S(O)2-OH.
H2SO5 is sometimes confused with H2S2O8, known as peroxydisulfuric acid. The disulfuric acid, which appears to be more widely used as its alkali metal salts, has the structure HO-S(O)2-O-O-S(O)2-OH.
Contents |
[edit] History
H2SO5 was first described by Heinrich Caro, for whom it is named.
[edit] Synthesis and production
The laboratory scale preparation of Caro's acid involve the combination of chlorosulfonic acid and hydrogen peroxide.
- H2O2 + ClSO2OH ⇌ H2SO5 + HCl
Large scale production of Caro's acid is usually done on site, due to its instability. According to the patent by Martin, Caro's acid is produced by reacting >85% sulfuric acid and >50% hydrogen peroxide ("Piranha solution").
- H2O2 + H2SO4 ⇌ H2SO5 + H2O
[edit] Potassium peroxymonosulfate
The derivative of peroxysulfuric acid, KHSO5 is widely used as an oxidizing agent. The potassium salt is marketed by two companies: Degussa under the tradename Caroat® and DuPont under the tradename Oxone®, tradenames which are now part of standard chemistry vocabulary. It is a component of a triple salt with the formula 2KHSO5·KHSO4·K2SO4. The standard electrode potential for this compound is -1.44 V with a half reaction generating the hydrogen sulfate.
- HSO4- + H2O → HSO5- + 2 H+ + 2 e-
Illustrative of the oxidation power of this salt is the conversion of an acridine to the corresponding acridine-N-oxide.1
and the oxidation of a thioether to a sulfone 2 (with 2 equivalents). With one equivalent the reaction converting sulfide to sulfoxide is much faster than that of sulfoxide to sulfone, so the reaction can conveniently be stopped at that stage if so desired.
[edit] Uses in industry
H2SO5 has been used for a variety of disinfectant and cleaning applications, e.g., swimming pool treatment and denture cleaning. Alkali metal salts of H2SO5 show promise for the delignification of wood.
Ammonium, sodium, and potassium salts of H2SO5 are used in the plastics industry as polymerization initiators, etchants, desizing agents, soil conditioner, and for decolorizing and deodorizing oils.
[edit] References
- Martin, P. L. (USA). U.S. Pat. Appl. Publ. (2005), 21 pp. CODEN: USXXCO US 2005031530 A1 20050210 Patent written in English. Application: US 2004-878176 20040628. Priority: US 2003-494009 20030807. CAN 142:179838 AN 2005:122569 CAPLUS
- "Treatment of Softwood Kraft Pulps with Peroxymonosulfate Before Oxygen Delignification. Springer, E. L.; McSweeny, J. D. Tappi Journal (1993), 76, 194-9.
- 1 Thomas W. Bell, Young-Moon Cho, Albert Firestone, Karin Healy, Jia Liu, Richard Ludwig, and Scott D. Rothenberger Organic Syntheses, Coll. Vol. 8, p.87; Vol. 69, p.226 Article
- 2 James R. McCarthy, Donald P. Matthews, and John P. Paolini Organic Syntheses, Coll. Vol. 9, p.446; Vol. 72, p.209 Article
