Names | |
---|---|
IUPAC names
Peroxysulfuric acid
Sulfuroperoxoic acid [1] | |
Systematic IUPAC name | |
Other names
Peroxosulfuric acid
[1]
Peroxomonosulfuric acid[ citation needed] Persulfuric acid[ citation needed] Caro's acid | |
Identifiers | |
3D model (
JSmol)
|
|
ChEBI | |
ChemSpider | |
ECHA InfoCard | 100.028.879 |
EC Number |
|
101039 | |
PubChem
CID
|
|
UNII | |
UN number | 1483 |
CompTox Dashboard (
EPA)
|
|
| |
| |
Properties | |
H 2SO 5 | |
Molar mass | 114.078 g mol−1 |
Appearance | White crystals |
Density | 2.239 g cm−3 |
Melting point | 45 °C |
Acidity (pKa) | 1, 9.3 [3] |
Conjugate base | Peroxomonosulfate |
Structure | |
Tetrahedral at S | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards
|
strong oxidizer |
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
|
Peroxymonosulfuric acid, H
2SO
5, is also known as persulfuric acid, peroxysulfuric acid, or Caro's acid. 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. It is one of the strongest oxidants known (
E0 = +2.51 V) and is highly explosive.
H
2SO
5 is sometimes confused with H
2S
2O
8, 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.
H
2SO
5 was first described in 1898 by the German chemist
Heinrich Caro, after whom it is named.
[4]
The laboratory scale preparation of Caro's acid involves the combination of chlorosulfuric acid and hydrogen peroxide: [5]
Published patents include more than one reaction for preparation of Caro's acid, usually as an intermediate for the production of potassium monopersulfate (PMPS), a bleaching and oxidizing agent. One patent for production of Caro's acid for this purpose gives the following reaction: [6]
This is the reaction that produces the acid transiently in " piranha solution".
H
2SO
5 has been used for a variety of disinfectant and cleaning applications, e.g., swimming pool treatment and denture cleaning. Alkali metal salts of H
2SO
5 show promise for the
delignification of wood.
[7] It is also used in laboratories as a last resort in removing organic materials since H
2SO
5 can fully
oxidize any organic materials.[
citation needed]
Ammonium,
sodium, and
potassium salts of H
2SO
5 are used in the
plastics industry as
radical initiators for
polymerization. They are also used as
etchants,
oxidative desizing agents for textile fabrics, and for decolorizing and deodorizing oils.
Potassium peroxymonosulfate, KHSO
5, is the
potassium
acid salt of peroxymonosulfuric acid. It is widely used as an
oxidizing agent.
Pure Caro's acid is highly explosive. Explosions have been reported at Brown University [8] and Sun Oil. 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 these compounds, creating highly unstable molecules such as acetone peroxide.