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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Dissociation constant

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Reference
Endpoint:
dissociation constant
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Qualifier:
no guideline followed
Principles of method if other than guideline:
Theoretical calculation of dissociation constant using ACD Labs Software.
GLP compliance:
no
Dissociating properties:
no
No.:
#1
pKa:
16.62
Temp.:
20 °C
Remarks on result:
other: for amide group (acidic)
No.:
#2
pKa:
14.48
Temp.:
20 °C
Remarks on result:
other: for OH group (mostly acidic)
No.:
#3
pKa:
-0.7
Temp.:
20 °C
Remarks on result:
other: for amide group (mostly basic)

There are three dissociation constants observed, two relating to the amide gorup and one relating to the hydroxyl group. The NH group can either lose a hydrogen at 16.62 to become N- or can gain a hydrogen at -0.7 to become NH2 +. However, none of the values obtained indicate a dissociation constant within the environmentally relevant pH range of 5 -9.

Conclusions:
The dissociation constants estimated for this substance are outside the range of environmentally relevant pH range of 5-9.
Executive summary:

A study was conducted to determine the dissociation constant of the test substance using ACD Labs softwater. Using the software, three dissociation constants were observed, two relating to the amide gorup (pKa: 16.62 and -0.7) and one relating to the hydroxyl group (pKa: 14.48). The two values for the amide group indicates that the NH group can either lose a hydrogen at 16.62 to become N- or can gain a hydrogen at -0.7 to become NH2 +. However, none of the values obtained indicate a dissociation constant within the environmentally relevant pH range of 5 -9. Therefore, based on the results, the test substance is not considered to dissociate at environmentally relevant pH range of 5 -9 (Halfpenny, 2013).

Description of key information

The dissociation constant of the test substance was determined using ACD Labs software (Halfpenny, 2013)

Key value for chemical safety assessment

Additional information

Three dissociation constants were estimated, two relating to the amide gorup (pKa: 16.62 and -0.7) and one relating to the hydroxyl group (pKa: 14.48). The two values for the amide group indicates that the NH group can either lose a hydrogen at 16.62 to become N- or can gain a hydrogen at -0.7 to become NH2 +. None of the values obtained indicate a dissociation constant within the environmentally relevant pH range of 5 -9. Therefore, the test substance is not considered to dissociate.