Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Currently viewing:

Administrative data

Link to relevant study record(s)

dissociation constant
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11 Mar 1992
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
no guideline followed
Principles of method if other than guideline:
By inspection of the chemical formula it can be expected that the test compound, will have no pK in an accessible range.
Nevertheless the following test was conducted:
4.463 mg of the test compound was dissolved in 25 mL methanol.
1 mL of this solution was diluted 1:10 with each of the following solutions:
0.1 N HCl (pH 1.0)
0.067 M Phosphate buffer (pH 7.0)
0.072 M Borax buffer (pH 10.0)
At each pH, absorption spectra in the range 210 to 320 nm were taken using a spectrophotometer Lambda 16 (1 cm cells, room temperature).
GLP compliance:
Dissociating properties:
Remarks on result:
not determinable
the test substance has no dissociation within the range pH 1 to pH 10 at room temperature.


The obtained spectra, with the test substance at pH 1, pH 7 and pH10, were identical indicating that there is indeed no pKa in the range pK 0 to at least pK 10.

The test substance does not dissociation within the range pH 1 to pH 10.
Executive summary:

A study was performed to evaluate the dissociation constant of the test substance in water in compliance with GLP. The spectra recorded using a neutral, acidic and basic solution lead to the conclusion that no dissociation was to be expected within the range pH 1 to pH 10.

Description of key information

No dissociation at the range of pH 1 - 10, test substance was prepared in methanol, spectrophotometer, Jäkel 1992.

Key value for chemical safety assessment

Additional information