Halazone


Halazone benzoic acid) is a chemical compound with the formula can be written as, or. It has been widely used to disinfect drinking water.
Other names for this compound include p-sulfondichloramidobenzoic acid, 4-benzoic 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.
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 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 3 days or less, unlike iodine-based tablets which have a usable open bottle life of three months.
Dilute halazone solutions has also been used to disinfect contact lenses, and as a spermicide.

Mechanism of action

Halazone's disinfecting activity is mainly due to the hypochlorous acid released by hydrolysis of the chlorine-nitrogen bonds when the product is dissolved in water:
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.
Another synthesis route is the oxidation of dichloramine-T with potassium permanganate in a mild alkaline medium.