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Physical & Chemical properties

Dissociation constant

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Description of key information

The overall behaviour of FAT 40825/A in aqueous solutions will be dominated by the strongly acidic arenesulfonic acid groups (ArSO3H, pKa -6.7). Therefore, the molecule will be negatively charged and is present in its anionic form over the whole environmentally relevant pH range.

Key value for chemical safety assessment

pKa at 20°C:
-6.7

Additional information

The purpose of this study was to estimate the dissociation constants (pKa-values) of FAT 40825/A. The molecular structure of FAT 40825/A was used for the estimation of the dissociation behaviour. The compound has several sites, which can be dissociated (acids) and one site, which can be protonated (base). The estimations are mainly based on the Hammett and Taft equations.

The overall behaviour of FAT 40825/A in aqueous solutions will be dominated by the strongly acidic arenesulfonic acid groups (ArSO3H, pKa -6.7). Therefore, the molecule will be negatively charged and is present in its anionic form over the whole environmentally relevant pH range from approximately pH 4 to 9.