Potassium peroxymonosulfate

"Oxone" redirects here. Not to be confused with the gas ozone.

Not to be confused with Potassium persulfate.

Potassium peroxymonosulfate

Names
IUPAC name Potassium peroxysulfate
Other names Potassium peroxymonosulfate, potassium hydrogen persulfate, potassium caroate/Caro's acid potassium salt; monopersulfate and potassium monopersulfate (MPS and KMPS); Oxone®, Caroat®, etc. (but see text).
Identifiers
CAS Number	10058-23-8 Y 37222-66-5 (triple salt) Y 70693-62-8 Y
3D model (JSmol)	Interactive image
ChemSpider	8053100 N
ECHA InfoCard	100.030.158
PubChem CID	11804954
UNII	040ZB27861 Y HL6A2XXU5D (triple salt) Y
CompTox Dashboard (EPA)	DTXSID1034840
InChI InChI=1S/K.H2O5S/c;1-5-6(2,3)4/h;1H,(H,2,3,4)/q+1;/p-1 N Key: OKBMCNHOEMXPTM-UHFFFAOYSA-M N InChI=1S/K.H2O4S/c;1-4-5(2)3/h;1H,(H,2,3)/q+1;/p-1 Key: GZHFEBOLZPYNER-UHFFFAOYSA-M InChI=1/K.H2O5S/c;1-5-6(2,3)4/h;1H,(H,2,3,4)/q+1;/p-1 Key: OKBMCNHOEMXPTM-REWHXWOFAJ
SMILES [K+].[O-]S(=O)(=O)OO
Properties
Chemical formula	KHSO5
Molar mass	152.2 g/mol (614.76 g/mol as triple salt)
Appearance	Off-white powder
Solubility in water	Decomposes
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Oxidant, corrosive
NFPA 704 (fire diamond)	3 0 1
Safety data sheet (SDS)	ChemicalBook.com SDS
Related compounds
Related compounds	Potassium persulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Potassium peroxymonosulfate, also referred to as potassium peroxysulfate and potassium monopersulfate (KMPS), formula KHSO₅, is a chemical compound that is the mono-potassium salt of peroxymonosulfuric acid (Caro's acid) In common applications, it is often referred to more simply as monopersulfate, MPS, or by one of its commercial names—as it is a constituent of widely used oxidizing agents, for instance, the triple salt 2KHSO₅·KHSO₄·K₂SO₄ known especially by its early trade name, Oxone® (from DuPont de Nemours). In such formulations, it functions under a variety of conditions, including homogeneous solutions and biphasic mixtures, as a stoichiometric oxidizing agent. Underlying that use is its standard electrode potential, which for potassium peroxymonosulfate, per se, is +1.81 V (half reaction generating hydrogen sulfate, HSO₄^–). Applications of agents that include the MPS compound extend, for example, to uses in laboratory and industrial oxidative chemical conversions, and in practical cleaning, whitening, and disinfection contexts.

Synonyms

The title compound is referred to by the IUPAC as potassium peroxysulfate, and more generally, as well, by a long series of more and less common name variants that alter the order of the name components (potassium, the peroxy-function, and the sulfuryl-core), sometimes altering the "peroxy-" to "peroxo-", and sometimes inserting "hydrogen" or "mono-" as a prefix preceding the sulfuryl component. Frequently seen names include the IUPAC and title names, as well as potassium monopersulfate (KMPS) and its shortened variant, monopersulfate (MPS), potassium hydrogen persulfate, and names derived from it's precursor, Caro's acid (potassium caroate and Caro's acid potassium salt). The title compound is sometimes stated as being informally synonymous with commercial preparations containing it, e.g., Oxone® and Caroat®, see following. For further explicit variations, see the CAS Common Chemistry entry for the title compound.

Properties

Chemical properties

Potassium peroxymonosulfate, KHSO₅, is the mono-potassium salt of peroxymonosulfuric acid (Caro's acid). Its discussion often centers on its formulations as a triple salt 2KHSO₅·KHSO₄·K₂SO₄, which is sold under registered trademarks, e.g., Oxone®, Curox®, and Caroat®. Description of chemical and physical properties must make clear whether one is describing research aspects of the pure substance, versus the aspects of the widely used, commercially available formulations.

Purity of preparations and reagents containing the title compound can be determined by iodometric titration. A practical encyclopedia or organic reagents has indicated that the presence of heavy metal salts catalyzes the decomposition of the title compound in its triple salt formulation.

Electrochemistry

The standard electrode potential for potassium peroxymonosulfate is +1.81 V with a half reaction generating the hydrogen sulfate (pH = 0):

HSO−5 + 2H⁺ + 2e⁻ → HSO−4 + H₂O .

Physical properties

The formulation of the title compound as the triple salt, 2KHSO₅·KHSO₄·K₂SO₄, was created to provide a form of KHSO₅ that is "convenient to handle and store"; in this formulation, it is a "white, granular, free flowing solid", its density is reported as 1.12–1.20 grams per cubic centimeter, and it is reported to decompose on melting point measurement. The same formulation is described as being soluble in water (25.6 grams per 100 grams water at 20◦C), as well as in aqueous methanol, ethanol, and acetic acid, but as being insoluble in "common organic solvents". It can, however, be applied in biphasic systems, owing to its water solubility, through use of "an immiscible cosolvent and a phase-transfer catalyst".

Toxicity

Formulated as its triple salt, the title compound and its co-formulants have low toxicity, but nevertheless require adequate ventilation (and standard chemical handling precautions) for its use, to reduce exposure to its dust, which is "irritating to the eyes, skin, nose, and throat".

Triple salt formulations (Oxone®, etc.)

The potassium peroxymonosulfate-containing formulation, the triple salt 2KHSO₅·KHSO₄·K₂SO₄, has a molecular weight of 614.7, with KHSO₅ composing, in 2008 (during its manufacture by DuPont, see following), an estimated 43-45% of it, by weight, of which 5.2% active oxygen was theoretically possible, and 4.7% was typically observed. (In 2012, a review was reporting the KHSO₅ estimate to be "about 50% per mole" of triple salt.) The stability advantage notwithstanding (see following), methods were developed to deliver a forms of the title compound that required smaller amounts in reactions, and this was achieved on large scale in 2002 via preparations of purified KHSO₅·H₂O.

The triple salt formulations have a longer shelf life than potassium peroxymonosulfate, per se. Available in commercial formulations, originally from DuPont deNemours Chemical (early trade name, Oxone®), now from Lanxess Deutschland Gmbh (as Oxone™), it has also been available from other manufacturers under other trade names (e.g., as Curox® and Caroat®). These products are of wide commercial value.

The triple salt products are produced from peroxysulfuric acid, which is generated in situ by combining fuming sulfuric acid (oleum) and hydrogen peroxide. Careful neutralization of this solution with potassium hydroxide allows the crystallization of the triple salt.

Uses

Cleaning

Oxone®-type products is used widely for oxidative processes that result in decomposition of organic contaminants, and therefore in cleaning, whitening, and disinfection. For instance, it can be used to whiten materials used in dental health practices, to clean materials in the manufacture of microelectronics, and sees extensive use as an oxidizer to decompose organic contaminants in swimming and other recreational water pools. Use of formulations containing the title compound in pool water quality management can interfere with determinations of chlorination assay, using a standard ferrous ammonium sulfate, N,N′-diethyl-p-phenylenediamine (FAS-DPD) method, if added reagents and steps are not followed to neutralise the KMPS (potassium monopersulfate / peroxymonosulfate).

Preparative chemistry

Potassium peroxymonosulfate and Oxone®-type products are versatile oxidants in organic chemistry and other synthetic arenas. Oxone®-type products oxidize terminal alkenes to epoxides, and cleave internal alkenes, providing two equivalents of carboxylic acid. They can be used to convert aldehydes to carboxylic acids; in the presence of alcoholic solvents, the corresponding esters may be obtained.

Oxone®-type products convert ketones to dioxiranes, which can be used for diverse oxidations in organic synthesis. The reagent dimethyldioxirane (DMDO) forms upon treatment of acetone with an Oxone®-type product; dioxiranes are versatile oxidants, especially in the epoxidation of olefins, and in the oxidation of other unsaturated functionalities, heteroatoms, and even some alkane C-H bonds.

The Shi epoxidation

Oxone®-type products are used in the production of some organic periodinanes, notably the oxidation of 2-iodobenzoic acid to 2-iodoxybenzoic acid (IBX).

Oxidation of 2-iodobenzoic acid to IBX

Peroxymonosulfate-driven conversions can be used with sulfides and selenides to prepare sulfones and selenones, with anilines and amino sugars to provide nitro compunds, oximes to provide nitro compunds (in aqueous buffered conditions) or to return the parent carbonyl compounds (in the presence of alumina, with microwave heating), primary and secondary amines to provide hydroxylamines (using adsorbed Oxone®) or N-nitrosation products (in the presence of sodium nitrite), pyridines and tertiary amines to provide amine oxides, and phosphorus(III) compounds to provide phosphono-compounds largely retaining configuration at phosphorus (with comparable outcomes when a sulfur or selenium atom replaces the phosphorus(III) lone pair).

Examples of preparative scale oxidatives of these types are the conversion of an acridine derivative to the corresponding acridine-N-oxide, and the synthesis of fluoromethyl phenyl sulfone, a reagent used in the synthesis of fluoroalkenes.

The drawback of peroxymonosulfate anion insolubility in organic solvents (and thus proscription to aqueous, alcoholic, and phase transfer reaction conditions) has been addressed through the preparation of organic-soluble salts of Caro's acid, to replace the potassium of the title compound and Oxone®-type products; several have been prepared—e.g., the tetra-n-butylammonium, tetraphenylphosphonium, and benzyltriphenylphosphonium salts (nBu₄NHSO₅, Ph₄PHSO₅, and BnPh₃PHSO₅)—and they have been studied and found comparable in reactivity "in many cases" to Oxone®-type products.

Other preparative chemical applications

In addition to the title compound, ammonium and sodium salts of HSO−5 are used in the plastics industry as radical initiators for polymerization. The title compound or its formulations have been used for decolorizing and deodorizing oils, as etchants, and as oxidative desizing agents for textile fabrics. It has also been investigated for use in processes aimed at delignification of wood.

Further reading

• Crandall, Jack K.; Shi, Yian; Burke, Christopher P.; Buckley, Benjamin R. (September 14, 2012) [2001]. Paquette, Leo A. (ed.). Encyclopedia of Reagents for Organic Synthesis. New York, NY: Wiley & Sons. doi:10.1002/047084289x.rp246.pub3. ISBN 9780470842898. Retrieved November 3, 2025. The original 1995 print publication of this chapter by Crandall was vol. 3, on pages 295ff.

• DuPont Staff (2008). "DuPont™ Oxone® Monopersulfate Compound / General Technical Attributes" (PDF). du Pont de Nemours. Wilmington, DE: E.I. du Pont de Nemours & Co. Retrieved November 3, 2025 – via Ataman Kimya A.Ş.(AtamanKimya.com).

• Jakob, Harald; Leininger, Stefan; Lehmann, Thomas; Jacobi, Sylvia & Gutewort, Sven (July 15, 2007). "Peroxo Compounds, Inorganic". In Ley, Claudia (ed.). Ullmann's Encyclopedia of Industrial Chemistry. Weinheim, Germany: Wiley-VCH. doi:10.1002/14356007.a19_177.pub2. Retrieved November 3, 2025.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

• Mundy, B.P.; Ellerd, M.G. & Favaloro Jr., F.G. (2005). "Oxone®". Name Reactions and Reagents in Organic Synthesis (2nd ed.). Hoboken, NJ: John Wiley & Sons. p. 828. ISBN 9780471739869. Retrieved November 3, 2025.{{cite book}}: CS1 maint: multiple names: authors list (link)

• Page, P.C.B.; Barros, D.; Buckley, B.R.; Ardakani, A. & Marples, B.A. (2004). "Organocatalysis of Asymmetric Epoxidation Mediated by Iminium Salts under Nonaqueous Conditions". J. Org. Chem. 69 (10): 3595–3597. doi:10.1021/jo035820j. Retrieved November 3, 2025.{{cite journal}}: CS1 maint: multiple names: authors list (link) Presents an organic-soluble form of Oxone®, tetraphenylphosphonium peroxymonosulfate (Ph₄PHSO₅), and its successful deployment in the asymmetric epoxidation using peroxymonosulfate-generated oxaziridinium salts.

• Travis, B. R.; Ciaramitaro, B. P. & Borhan, B. (September 30, 2002). "Preparation of Purified KHSO₅·H₂O and nBu₄NHSO₅ from Oxone by Simple and Efficient Methods". Eur. J. Org. Chem.: 3429–3434. doi:10.1002/1099-0690(200210)2002:20<3429::AID-EJOC3429>3.0.CO;2-D. Retrieved November 3, 2025.{{cite journal}}: CS1 maint: multiple names: authors list (link) The article has been made available by an author, at this link.