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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Link to relevant study record(s)

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Endpoint:
dissociation constant
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
structural similarity
Reason / purpose for cross-reference:
read-across source
Dissociating properties:
no
No.:
#1
pKa:
-0.75
Remarks on result:
other: QSAR ChemAxon

The source substance has the same functional groups when compared to the target substance. Hence, the result is considered relevant for the target substance as well.

Conclusions:
pKa is outside pH 5 to 9.
Executive summary:

The dissociation constant of docusate sodium as calculated with the QSAR ChemAxon is given as -0.75. Based on the same functional groups of the source and target substance the result is considered to be relevant for the target substance as WoE approach.

The pkA can be predicted to be outside the range of 5 - 9 which is given as criterion in R.7.a. Hence, the study is not needed.

Endpoint:
dissociation constant
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Principles of method if other than guideline:
Assessment of the pKa based on the molecular structure of the registered substance.
GLP compliance:
no
Dissociating properties:
no
Remarks:
The registered substance has no dissociating groups.

The registered substance has no dissociating groups. Hence, a study for the determination of the dissociation constant is not needed.

Conclusions:
The registered substance has no dissociating groups.
Executive summary:

The registered substance has no dissociating groups.Hence, a study for the determination of the dissociation constant is not needed.

Endpoint:
dissociation constant
Type of information:
not specified
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Principles of method if other than guideline:
Assessment of the pKa based on the molecular structure of the registered substance.
GLP compliance:
no
Dissociating properties:
no
Remarks:
The registered substance has no dissociating groups.

The registered substance is a salt. As stated in Guidance R.7a section R.7.1.17.1 "It is important to note that the dissolution of salts from their crystal lattice into individual ions is not intended to be covered by the endpoint dissociation constant. Therefore this section refers only to acid dissociation (pKa)."

Conclusions:
The registered substance is a salt. As stated in Guidance R.7a section R.7.1.17.1 "It is important to note that the dissolution of salts from their crystal lattice into individual ions is not intended to be covered by the endpoint dissociation constant. Therefore this section refers only to acid dissociation (pKa)."
Executive summary:

The registered substance is a salt. As stated in Guidance R.7a section R.7.1.17.1 "It is important to note that the dissolution of salts from their crystal lattice into individual ions is not intended to be covered by the endpoint dissociation constant. Therefore this section refers only to acid dissociation (pKa)."

Description of key information

The dissociation constant is not relevant since the substance is a salt.


The registered substance has no dissociating groups.Hence, a study for the determination of the dissociation constant is not needed.


Evidence that the pKa is about -0.75 is provided. With this pKa there is no significant dissociation within pH 5 to 9.

Key value for chemical safety assessment

Additional information