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Physical & Chemical properties

Dissociation constant

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Description of key information

Dissociation constants (hexahydrophthalic acid): pKa1= 4.14 and pKa2= 6.52 at 20 ± 1 °C.

Key value for chemical safety assessment

pKa at 20°C:
4.14

Additional information

The dissociation constants in water of hexahydrophthalic acid (HHPAc), the di-acid hydrolysis product of cyclohexane-1,2-dicarboxylic anhydride (HHPA), has been investigated in accordance with OECD test methods and determined to be: pKa1= 4.14 and pKa2= 6.52 at 20 ± 1 °C.

The species distribution generated by the dissociation of this acid was determined, according to these constants, as function of pH.