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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Description of key information

Experimental data could not be determined according to OECD guideline 112.
Calculated results:
pKa1 = 15.10 ± 0.10, pKa1 is associated with the hydroxyl group.
pKa2 = 1.39 ± 0.50, pKa2 is associated with the sulfonic acid function.

Key value for chemical safety assessment

Additional information

A guideline study (OECD 112) did not deliver results for the dissociation constants of sodium 2 -hydroxyethanesulphonate. Therefore, a calculation was performed for the corresponding 2-hydroxyethanesulphonic acid with a commercially available software tool. Two values for the two functional groups were predicted. Each value is provided with its 95% confidence limits:

pKa1 = 15.10 ± 0.10, pKa1 is associated with the hydroxyl group.

pKa2 = 1.39 ± 0.50, pKa2 is associated with the sulfonic acid function.

The calculated data are consistent with what would be expected for the functional groups present in the molecule.

From this data it can be concluded that under environmental relevant conditions 2 -hydroxyethanesulphonic acid exists only in its single ionized form, represented by the hydroxysulfonate anion.