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Dissociation constant

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Description of key information

Dissociation constant [1-(tert-butyldimethylsilyl)piperazine]: Not relevant due to very rapid hydrolysis


Dissociation constant [piperazine]: pKa1 = 9.73 and pKa2 = 5.33

Key value for chemical safety assessment

Additional information

The requirement to conduct a dissociation constant study for the submission substance is waived because in contact with water, it hydrolyses very rapidly to form tert-butyldimethylsilanol and piperazine.

The silanol hydrolysis product is not expected to dissociate within relevant pH associated with environmental assessment.

Piperazine has reported pKa1 = 9.73 and pKa2 = 5.33 (Perrin DD 1972).


Perrin DD (1972). Dissociation Constants of Organic Bases in Aqueous Solution. IUPAC Chemical Data Series: Supplement. Buttersworth, London