Registration Dossier
Registration Dossier
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EC number: 247-728-7 | CAS number: 26479-35-6
Dissociation constant
Administrative data
Link to relevant study record(s)
Description of key information
In a study performed according to Organisation for Economic Co-operation and Development (OECD) Testing Guideline 112, the acid dissociation (Ka) constants for allophanic acid (CAS No. 625-78-5) were determined. The logarithms of the Ka values (pKa) for the three ionisable protons correspond to 5.0, 6.5 and 8.6.
Key value for chemical safety assessment
- pKa at 20°C:
- 5
Additional information
Investigations of the acid dissociation constant requires testing of a compound in its most protonated state. The most protonated state of potassium allophonate is allophanic acid (CAS No. 625-78-5), which is a triprotic; therefore, the log values of the acid dissociation constants (pKa) were determined to be 5.0 (pKa1), 6.5 (pKa2) and 8.6 (pKa3), indicating that allophanic acid will be negatively charged at environmental pH (Intertek ASG, 2010d).
Reference:
Intertek ASG. 2010d. Study 1320994 pKa value. Testing Laboratory: Intertek ASG. Report no.: 1320994. Owner company: Kerr Fire Fighting Chemicals. Report date: 2010-09-11.
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