Dichloroisocyanuric acid

Synthesis

Dichloroisocyanuric acid is manufactured by chlorination of cyanuric acid: :(C(O)NH)3 + 2 Cl2 → (C(O)NCl)2(C(O)NH) + 2 HCl It is a colourless solid.

Mechanism of action

Dichloroisocyanuric acid is an oxidizer, reacting with water to form chlorine gas.

Although the bleaching agent in most chlorine based bleach is sodium hypochlorite, the sodium salt of dichloroisocyanuric acid, sodium dichloroisocyanurate, is the active ingredient in commercial disinfectant bacteriocides, algicides, and cleaning agents such as the pulverized cleanser Comet.

When dissolved in water, cyanuric acid forms a weak bond with dissolved chlorine, protecting it from breakdown by the sun's UV rays while not preventing the chlorine from oxidizing contaminants. For outdoor pools, dichlor should be added until cyanuric acid levels reach 30-50 ppm. Thereafter, sodium hypochlorite or other forms of chlorine can be used to maintain sanitation levels without continuing to add additional cyanuric acid to the system. At very high levels, cyanuric acid can reduce the ability of free chlorine to eliminate certain microbial contaminants.

References

References

1. "Cyanuric Acid and Cyanuric Chloride".
2. (Apr 17, 2021). "Pubchem Dichloroisocyanuric acid".
3. "Alfa Aesar™ Dichloroisocyanuric acid sodium salt, 97% (dry wt.), water <3%".
4. (Oct 15, 2013). "Procter&Gamble MSDS Comet Powder".
5. "Fact Sheet on Cyanuric Acid and Stabilized Chlorine Products".