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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Phototransformation in air

The atmospheric oxidation potential (AOP) predicted from the Epiwin program indicates that cyanuric chloride is not photolytically reactive (degradation half-life of > 15 year).


Measurements revealed a fast and stepwise hydrolysis of cyanuric chloride. The intermediate and final degradation products of cyanuric chloride were identified as 2,4-dichlor-6-hydroxy-1,3,5-triazine (first intermediate, DT50(pH 7.0, T=298.15 K = 0.52 h = 31.5 min), 2-chlor-4,6-dihydroxy-1,3,5-triazine (also named 6-chloro-1,3,5-triazine-2,4(1H,3H)-dione, sodium salt) (second intermediate, CAS no.: 32998-00-8, DT50 (pH 7.0, T=298.15 K)= 3.98 h =239.0 min ) and cyanuric acid (final degradation product, CAS no: 108 -80-5), respectively.

In this non guideline study the half-times for the first hydrolysis step of cyanuric chloride were determined to be

- DT50(pH 2.0, T=298.15 K = 1.2 min

- DT50 (pH 4.0, T=313.15 K)= 1.65 min

- DT50(pH 7.0, T= 298.15 K) = 3.47 min.

The rates of hydrolysis rise significantly for all three steps at acidic medium and are slower at basic pH (for T = constant).

The activation energy is idependent from pH and equal for the three hydrolysis steps.

Phototransformation in water

Cyanuric acid (concantration: ca. 275 mg/L) was treated both with UV radiation and with UV-irradiated H2O2. After 30 minutes treatment the concentration of the the test item (cyanuric acid) that was treated with UV radiation and with UV-irradiated H2O2 was determined to be ca. 225 mg/L and ca. 275 mg/L, respectively. Since these concentrations do not differ strongly from the initial test item concentration, photodegradation of the test item is not considered.