Peroxymonosulfuric acid, , also known as persulfuric acid, peroxysulfuric acid, or Caro's acid. In this

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

, 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 pe ...

. 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 Heinrich Caro (February 13, 1834 in Posen, Prussia Germany now Poznań, Poland – September 11, 1910 in Dresden), was a German chemist. He was a Sephardic Jew. He started his study of chemistry at the Friedrich Wilhelms University and later ...

, after whom it is named.

Synthesis and production

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

chlorosulfuric acid Chlorosulfuric acid (IUPAC name: sulfurochloridic acid) is the inorganic compound with the formula HSO3Cl. It is also known as chlorosulfonic acid, being the sulfonic acid of chlorine. It is a distillable, colorless liquid which is hygroscopic and ...

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 Piranha solution, also known as piranha etch, is a mixture of sulfuric acid () and hydrogen peroxide (), used to clean organic compound, organic residues off substrates. Because the mixture is a strong oxidizing agent, it will decompose most orga ...

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 a d ...

any organic materials.

Ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...

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 iso ...

, 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 atmosphe ...

salts of are used in the

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radical initiator In chemistry, radical initiators are substances that can produce radical species under mild conditions and promote radical reactions. These substances generally possess weak bonds—bonds that have small bond dissociation energies. Radical ini ...

s for

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

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

Potassium peroxymonosulfate Potassium peroxymonosulfate is widely used as an oxidizing agent. It is the potassium salt of peroxymonosulfuric acid. Usually potassium peroxymonosulfate refers to the triple salt known as oxone. The standard electrode potential for potassium ...

, , is the

acid salt Acid salts are a class of salts that produce an acidic solution after being dissolved in a solvent. Its formation as a substance has a greater electrical conductivity than that of the pure solvent. An acidic solution formed by acid salt is made duri ...

of peroxymonosulfuric acid. It is widely used as an

oxidizing agent An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or "Electron acceptor, accepts"/"receives" an electron from a (called the , , or ). In ot ...

Hazards

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

Brown University Brown University is a private research university in Providence, Rhode Island. Brown is the seventh-oldest institution of higher education in the United States, founded in 1764 as the College in the English Colony of Rhode Island and Providenc ...

and

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. 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