Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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


Based on results of the hydrolysis study, the half life at 25°C is estimated to be > 1 year, 6 days, and < 1 day at pH 4, 7, and 9, respectively.

Additional information

Reactive Orange 72/78 is degraded by hydrolysis at environmentally relevant pHs as can be derived from the read across from structural analogues which have a half-life time of 2 to 6 days at pH 7 and 25°C indicating the potential for significant removal by hydrolysis. Based on results of these hydrolysis studies, the half life at 25°C is > 1 year and < 1 day at pH 4 and 9, respectively. Studies on direct phototransformation in water are not available but it is assumed on the basis of chemical structure and nature of use that the substance is not degraded by direct photolysis.

It was found that the sulfonated azo dyes can be destroyed by UV photooxidation process (Saliha 2004). The kinetics of the degradation depends on the azo, benzene and naphthalene groups of the dyes. The first step of the degradation is related to cleavage of azo bond of the molecule and naphthalene ring which leads to further degradation until complete mineralization.

It is concluded, therefore, that abiotic processes would contribute significantly to the depletion of the substance within the environment.