View source for Peroxymonosulfuric acid

{{Chembox new
|   Name = Peroxymonosulfuric acid
|   ImageFile = Peroxymonosulfuric acid.svg
|   ImageFile1 = Caro's-acid-3D-balls.png
<!-- | ImageSize1 = 200px  -->
|   ImageName1 = Ball-and-stick model of peroxymonosulfuric acid
|   OtherNames = persulfuric acid, peroxysulfuric acid,<br /> peroxomonosulfuric acid;
| Section1 = {{Chembox Identifiers
|   CASNo = 7722-86-3
|   RTECS = 
  }}
| Section2 = {{Chembox Properties
|   Formula = H<sub>2</sub>SO<sub>5</sub>
|   MolarMass = 114.04 g/mol
|   Appearance = white solid
|   Density = ??? g/cm<sup>3</sup>, solid
|   Solubility = soluble
|   MeltingPt = 45 °C
|   BoilingPt = decomposes
  }}
| Section3 = {{Chembox Structure
|   Coordination = tetrahedral
|   CrystalStruct = 
|   Dipole = ?
  }}
| Section7 = {{Chembox Hazards
|   MainHazards = strong oxidizer
  }}
}}
'''Peroxymonosulfuric acid''', also known as '''persulfuric acid''', '''peroxysulfuric acid''', or as '''Caro's acid''', is  H<sub>2</sub>SO<sub>5</sub>, 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)<sub>2</sub>-OH.

H<sub>2</sub>SO<sub>5</sub> is sometimes confused with H<sub>2</sub>S<sub>2</sub>O<sub>8</sub>, 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)<sub>2</sub>-O-O-S(O)<sub>2</sub>-OH.
<!--what about (HOO)2SO2?, e.g. SO2Cl2 + 2 H2O2 to give the diperoxide?-->

==History==
H<sub>2</sub>SO<sub>5</sub> was first described  by [[Heinrich Caro]], for whom it is named.

==Synthesis and production==
The laboratory scale preparation of Caro's acid involve the combination of [[chlorosulfuric acid]] and [[hydrogen peroxide]].

::H<sub>2</sub>O<sub>2</sub> + ClSO<sub>2</sub>OH   {{unicode|⇌}}  H<sub>2</sub>SO<sub>5</sub>  + 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]]").

::H<sub>2</sub>O<sub>2</sub> + H<sub>2</sub>SO<sub>4</sub>   {{unicode|⇌}}  H<sub>2</sub>SO<sub>5</sub> + H<sub>2</sub>O

<!--probably also made electrochemically-->

==Uses in industry==
H<sub>2</sub>SO<sub>5</sub> has been used for a variety of disinfectant and cleaning applications, e.g., swimming pool treatment and denture cleaning.  Alkali metal salts of H<sub>2</sub>SO<sub>5</sub> show promise for the [[lignin|delignification]] of wood.

[[Ammonium]], [[sodium]], and [[potassium]] salts of H<sub>2</sub>SO<sub>5</sub> are used in the [[plastic]]s industry as [[polymerization]] initiators, etchants, desizing agents, [[soil conditioner]], and for decolorizing and deodorizing oils.

[[Potassium peroxymonosulfate]], KHSO<sub>5</sub>, is the [[potassium]] [[acid salt]] of peroxymonosulfuric acid. It is widely used as an [[oxidizing agent]].

==Dangers==
As with all strong oxidizing agents, peroxysulfuric acid should be kept away from organic compounds such as ethers and ketones because of its ability to peroxidize the compound, creating a highly unstable molecule such as [[Acetone Peroxide]].

==References==
{{Citationstyle|date=September 2007}}
{{reflist|2}}
*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.

[[Category:Sulfur oxoacids]]
[[Category:Sulfates]]
[[Category:Peroxides]]
[[Category:Peroxy acids]]

[[cs:Kyselina peroxosírová]]
[[de:Peroxomonoschwefelsäure]]
[[fr:Acide de Caro]]
[[it:Acido perossimonosolforico]]
[[nl:Peroxomonozwavelzuur]]
[[ja:過硫酸]]
[[ru:Кислота Каро]]