 | |
| Names | |
|---|---|
| Preferred IUPAC name 4-(Dichlorosulfamoyl)benzoic acid | |
Other names
| |
| Identifiers | |
| |
3D model (JSmol) | |
| ChEMBL | |
| ChemSpider |
|
| ECHA InfoCard | 100.001.140 |
| EC Number |
|
| UNII | |
| UN number | 1479 |
| |
| Properties | |
| C7H5Cl2NO4S | |
| Molar mass | 270.08 g·mol−1 |
| Appearance | Fine white powder with an odor of chlorine[2] |
| Melting point | 213 °C (415 °F; 486 K);[3] 196 °C with decomposition.[4] |
| Less than 1 g/L at 70 °F[2] | |
| Hazards | |
| GHS labelling: | |
 | |
| Warning | |
| H315,H319 | |
| P264,P280,P302+P352,P305+P351+P338,P321,P332+P313,P337+P313,P362 | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Halazone (4-(dichlorosulfamoyl)benzoic acid) is achemical compound whoseformula can be written as eitherC
7H
5Cl
2NO
4S or(HOOC)(C
6H
4)(SO
2)(NCl
2). It has been widely used to disinfect drinking water.
Other names for this compound includep-sulfondichloramidobenzoic acid,4-[(dichloroamino)sulfonyl]benzoic acid, andPantocide.
Halazone tablets have been used to disinfect water for drinking, especially wheretreated tap water is not available. A typical dosage is 4 mg/L.[5][6]
Halazone tablets were commonly used during World War II by U.S. soldiers forportable water purification, even being included in accessory packs forC-rations until 1945.[7]
Halazone was widely used by Marine infantry units during theVietnam War. Halazone has largely been replaced in that use bysodium dichloroisocyanurate. The primary limitation of halazone tablets was the very short usable life of opened bottles, typically three days or less, unlikeiodine-based tablets which have a usable open bottle life of three months.[citation needed]
Dilute halazone solutions (4 to 8ppm ofavailable chlorine) has also been used to disinfectcontact lenses,[8] and as aspermicide.
Halazone's disinfecting activity is mainly due to thehypochlorous acid (HClO) released byhydrolysis of thechlorine-nitrogen bonds when the product is dissolved in water:[8]
The hypochlorous acid is a powerfuloxidizer andchlorinating agent that destroys ordenatures many organic compounds.
Halazone can be prepared by chlorination ofp-sulfonamidobenzoic acid.[4]
Another synthesis route is the oxidation ofdichloramine-T withpotassium permanganate in a mild alkaline medium.[4]
