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Physical & Chemical properties

Dissociation constant

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Description of key information

The PALLAS pKa prediction for the test material demonstrates that the compound possesses an acidic group with a pKa of 12.62.

Key value for chemical safety assessment

pKa at 20°C:
12.62

Additional information

The prediction provided to address this endpoint was awarded a reliability score of 2 in accordance with the criteria of Klimisch et al. (1997).

The pKa of the test material was estimated using the pKalc function of the PALLAS estimation software program (CompuDrug, version 3.6.2.1).

The software program pKalc predicts the pKa values of compounds, based on a calculation which assumes that substituents produce free energy changes that are to a large extent additive.

At a constant temperature the pKa of a molecule is linearly related to the free energy change for the reaction of ionisation of a proton.

The insertion of a substituent leads to a corresponding change in free energy and therefore, a change in pKa. If these changes are small, they are found to be additive. This observation is the basis of the Hammett and Taft equations, which are widely used for pKa prediction.

The PALLAS pKa prediction for the test material demonstrates that the compound possesses an acidic group with a pKa of 12.62.