Halazone

Chemical compound From Wikipedia, the free encyclopedia

Halazone (4-(dichlorosulfamoyl)benzoic acid) is a chemical compound whose formula can be written as either C
7H
5Cl
2NO
4S or (HOOC)(C
6H
4)(SO
2)(NCl
2). It has been widely used to disinfect drinking water.

Quick facts Names, Identifiers ...
Halazone
Names
Preferred IUPAC name
4-(Dichlorosulfamoyl)benzoic acid
Other names
  • Pantocide
  • p-Sulfondichloramidobenzoic acid
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.001.140 Edit this at Wikidata
EC Number
  • 201-253-1
UNII
UN number 1479
  • InChI=1S/C7H5Cl2NO4S/c8-10(9)15(13,14)6-3-1-5(2-4-6)7(11)12/h1-4H,(H,11,12)[1]
    Key: XPDVQPODLRGWPL-UHFFFAOYSA-N[1]
  • O=C(O)c1ccc(S(=O)(=O)N(Cl)Cl)cc1
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:
GHS07: Exclamation mark
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 their standard state (at 25 °C [77 °F], 100 kPa).
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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.[5][6]

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.[7]

Halazone was widely used by Marine infantry units during the Vietnam War. 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.[citation needed]

Dilute halazone solutions (4 to 8 ppm of available chlorine) has also been used to disinfect contact lenses,[8] and as a spermicide.

Mechanism of action

Halazone's disinfecting activity is mainly due to the hypochlorous acid (HClO) released by hydrolysis of the chlorine-nitrogen bonds when the product is dissolved in water:[8]

(R1)(R2)NCl + H
2O → HOCl + (R1)(R2)NH

The hypochlorous acid is a powerful oxidizer and chlorinating agent that destroys or denatures many organic compounds.

Production

Halazone can be prepared by chlorination of p-sulfonamidobenzoic acid.[4]

Another synthesis route is the oxidation of dichloramine-T with potassium permanganate in a mild alkaline medium.[4]

See also

References

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