Registration Dossier

Diss Factsheets

Physical & Chemical properties

Dissociation constant

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

pKa at 20°C:
8.4

Additional information

The reaction mass of glycerol and thioglycolic acid is a complex mixture. Therefore, pKa values for individual components of the mixture were estimated by QSAR using SPARC (v. 4.5) chemical reactivity models for estimation ionization pKa in water. There are three types of ionisable groups present in the components of the reaction mass: thiol, hydroxyl and carboxyl groups. pKa values of individual components of the reaction mass are: 1,2-propanediol-3-sulfanylacetate: pKa,SH=8.40 at 20°C;

2-hydroxy-1,3-propanediyl bis(mercaptoacetate): pKa1,SH=8.07, pKa2,SH=8.68, pKa3,OH=13.78 at 20°C;

glycerol: does not dissociate in pH range -0.2 to 14 at 20°C;

1,3-propanediol-2-sulfanylacetate: pKa,SH=8.38 at 20°C;

mercaptoacetic acid: pKa1,COOH=3.76, pKa2,SH=10.04 at 20°C and

1,2,3-propanetriyl tris(mercaptoacetate): pKa1,SH=7.79, pKa2,SH=8.29, pKa3,SH=8.78 at 20°C.