Peroxymonosulfuric acid, , 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 ( ''E''⁰ = +2.51 V) and is highly explosive. is sometimes confused with , known as

peroxydisulfuric acid Peroxydisulfuric acid is an inorganic compound with a chemical formula . Also called Marshall's acid after Professor Hugh Marshall, who discovered it in 1891. Structure and bonding This oxoacid features sulfur in its +6 oxidation state and a ...

. 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.

History

was first described in 1898 by the German chemist Heinrich Caro, after whom it is named.

Synthesis and production

The laboratory scale preparation of Caro's acid involves the combination of chlorosulfuric acid and

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3 ...

: :: + ⇌ + HCl 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: :: + ⇌ + This is the reaction that produces the acid transiently in " piranha solution".

Uses in industry

has been used for a variety of disinfectant and cleaning applications, e.g., swimming pool treatment and denture cleaning. Alkali metal salts of show promise for the delignification of wood. It is also used in laboratories as a last resort in removing organic materials since can fully

oxidize Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or ...

any organic materials. Ammonium,

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

, and

potassium Potassium is the chemical element with the symbol K (from Neo-Latin '' kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmos ...

salts of are used in the plastics industry as radical initiators for

polymerization In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many f ...

. They are also used as etchants, oxidative desizing agents for textile fabrics, and for decolorizing and deodorizing oils. Potassium peroxymonosulfate, , is the

acid salt of peroxymonosulfuric acid. It is widely used as an oxidizing agent.

Hazards

Pure Caro's acid is highly explosive. Explosions have been reported at Brown University 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.

References

{{DEFAULTSORT:Peroxymonosulfuric Acid Hydrogen compounds Sulfur oxoacids Liquid explosives Persulfates Peroxy acids Oxidizing agents Explosive chemicals

History

Synthesis and production

Uses in industry

Hazards

See also

References