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Dissociation constant

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dissociation constant
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
accepted calculation method
according to guideline
other: no guideline followed
Version / remarks:
see "Principles of method if other than guideline"
not applicable
Principles of method if other than guideline:
Since the test item does not contain any functional groups likely to dissociate under normal conditions, no experimental work was performed. Instead, calculation of the dissociation constant using ACD/Labs I-Lab 2.0 was performed.
ACD/pKa calculates accurate acid-base ionization constants (pKa values) for 25°C and zero ionic strength in aqueous solutions. Each calculation is provided with its 95% confidence limits. The accuracy of calculations is usually better than ±0.2 pKa units (for very complex structures, better than ±0.5 pKa units).
GLP compliance:
Dissociating properties:

The predicted pKa values were in the range of 14.03 – 14.99 (95% confidence limits ± 0.1) for the hydroxyl groups and -3.74 – -2.59 (95% confidence limits ± 0.2) for the amine groups.


For details see attached document "pKa results from computer prediction.pdf".

The hydroxy groups of the test material will not dissociate under normal environmental conditions as the pKa values are not within the environmentally relevant pH range of 5-9 (see REACH Guidance on information requirements and chemical safety assessment, chapter R.7.1.17).

Description of key information

The test item does not contain any functional groups which are likely to dissociate under normal conditions.

Key value for chemical safety assessment

Additional information