Halazone (4-(dichlorosulfamoyl)benzoic acid) is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

whose

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

can be written as either or . It has been widely used to disinfect drinking water. Other names for this compound include ''p''-sulfondichloramidobenzoic acid, 4- dichloroamino)sulfonylenzoic acid, and Pantocide.

Uses

Halazone tablets have been used to disinfect water for drinking, especially where treated tap water is not available. A typical dosage is 4 mg/L.Gripo Laboratories:
Water purification range: Halazone USP based Chlorine Tablets
". Product page, accessed on 2018-06-18Precise Health Care PVT LTD:

". Product page, accessed on 2018-06-18 Halazone tablets were commonly used during World War II by U.S. soldiers for portable water purification, even being included in accessory packs for C-rations until 1945. Halazone was widely used by Marine infantry units during the

Vietnam War The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...

. Halazone has largely been replaced in that use by sodium dichloroisocyanurate. The primary limitation of halazone tablets was the very short usable life of opened bottles, typically three days or less, unlike iodine-based tablets which have a usable open bottle life of three months. Dilute halazone solutions (4 to 8 ppm of available chlorine) has also been used to disinfect

contact lens Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic ...

es, and as a

spermicide Spermicide is a contraceptive substance that destroys spermatozoon, sperm, inserted vaginally prior to Sexual intercourse, intercourse to prevent pregnancy. As a contraceptive, spermicide may be used alone. However, the pregnancy rate experienc ...

Mechanism of action

Halazone's disinfecting activity is mainly due to the

hypochlorous acid Hypochlorous acid is an inorganic compound with the chemical formula , also written as HClO, HOCl, or ClHO. Its structure is . It is an acid that forms when chlorine dissolves in water, and itself partially dissociates, forming a hypochlorite an ...

() released by

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

of the

chlorine Chlorine is a chemical element; it has Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between ...

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

bonds when the product is dissolved in water: : + → + The hypochlorous acid is a powerful

oxidizer 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 " accepts"/"receives" an electron from a (called the , , or ''electron donor''). In ot ...

and chlorinating agent that destroys or denatures many organic compounds.

Production

Halazone can be prepared by chlorination of ''p''-sulfonamidobenzoic acid. Another synthesis route is the oxidation of dichloramine-T with

potassium permanganate Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, which dissolves in water as K+ and ions to give an intensely pink to purple solution. Potassium permanganate is widely us ...

in a mild alkaline medium.

References

{{Antiseptics and disinfectants Antiseptics and disinfectants Benzoic acids Sulfonamides

Uses

Mechanism of action

Production

See also

References