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Physical & Chemical properties

Dissociation constant

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Description of key information

Dissociation constant (OECD 112): 5.8 at 22 °C (mean of 7 determinations) 

Key value for chemical safety assessment

pKa at 20°C:
5.8

Additional information

The key value was determined according to OECD Guideline 112 (Rocchio, 1990). The UV/Vis absorption spectrum at 300 nm is obtained from solutions of constant concentration under a pH condition where the substance is essentially unionized and fully ionized and at several intermediate pHs. From the pH and absorbance values at the chosen wavelength, seven values for the pKa are calculated using data from at least 5 pHs where the compound is at least 10 % and less than 90 % ionized.