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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Reference
Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data from peer-reviewed handbook or collection of data.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The dissociation constant was measured in an unsymmetrical cell with diffusion potentials. The pH was measured in buffer solutions using hydrogen electrodes.
GLP compliance:
no
Dissociating properties:
not determined
No.:
#1
pKa:
4.69
Temp.:
25 °C
Remarks on result:
other: Estimated uncertainty:
No.:
#2
pKa:
4.8
Temp.:
20 °C
Remarks on result:
other: Estimated uncertainty:
Conclusions:
The dissociation constant of the substance is 4.80 at 20°C and 4.69 at 25°C.
Executive summary:

The experimentally determined dissociation constant of m-toluidine was 4.80 at 20°C and 4.69 at 25°C, Perrin, 1965. Both values indicate that under environmental relevant pH (5 -9) the substance is present mainly in its neutral form.

Description of key information

The experimentally determined dissociation constant of m-toluidine was 4.80 at 20°C and 4.69 at 25°C.

Key value for chemical safety assessment

pKa at 20°C:
4.8

Additional information

The experimentally determined dissociation constant of m-toluidine is supported by a calculated pKa value of 4.7. The substance undergoes association (e.g. protonation) in water. Under environmental relevant pH (5 -9) the substance is present mainly in its neutral form.