Disodium oxybis[methylbenzenesulphonate]

Dissociation constant

Description of key information

The QSAR determination of the  dissociation constant (pKa) for ditolylether disulfonic acid disodium salt, isomer mixture was performed using the ACD 7.0 software. The obtained pKa values were < 0.
Ditolylether disulfonic acid disodium salt, isomer mixture is an UVCB substance consisting of positional isomers of two basic structures [sodium salts of disulfonated and trisulfonated ditolylether]. 
Since variations in the positions of the substituents have influence on calculations by the program, the calculations are performed using eight representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture. As generally dissociating properties of salts cannot be estimated by the program calculations were performed using the corresponding acids of representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture. 
The dissociation constants (pKa) of ditolylether disulfonic acid disodium salt, isomer mixture were estimated to be in a range of -0.61 to -0.10 for pKa1, in a range of -0.84 to -0.51 for pKa2 and in a range of -1.35 to -1.25 for pKa3. 
The predicted value can be considered as reliable  yielding a useful result for further assessment. 
According to the estimated results, ditolylether disulfonic acid disodium salt, isomer mixture will be present mainly in deprotonated form under environmentally relevant pH 5-9.

Key value for chemical safety assessment

pKa at 20°C:

0

Additional information

The result should be read as < 0.

The QSAR determination of the dissociation constant (pKa) for ditolylether disulfonic acid disodium salt, isomer mixture was performed using the ACD 7.0 software.

Ditolylether disulfonic acid disodium salt, isomer mixture is an UVCB substance consisting of positional isomers of two basic structures [sodium salts of disulfonated and trisulfonated ditolylether].

Since variations in the positions of the substituents have influence on calculations by the program, the calculations are performed using eight representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture. As generally dissociating properties of salts cannot be estimated by the program calculations were performed using the corresponding acids of representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture.

 

The corresponding acids of the representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture are:

A) 3-methyl-4-(3-methyl-4-sulfo-phenoxy)-benzenesulfonic acid

B) 2-methyl-4-(3-methyl-4-sulfo-phenoxy)-benzenesulfonic acid

C) 5-methyl-2-(2-methyl-4-sulfo-phenoxy)-benzenesulfonic acid

D) 5-methyl-2-(3-methyl-4-sulfo-phenoxy)-benzenesulfonic acid

E) 2-methyl-4-(2-methyl-4-sulfo-phenoxy)-benzene-1,3-disulfonic acid

F) 2-methyl-4-(3-methyl-4-sulfo-phenoxy)-benzene-1,3-disulfonic acid

G) 5-methyl-4-(4-methyl-2-sulfo-phenoxy)-benzene-1,3-disulfonic acid

H) 4-methyl-6-(4-methyl-2-sulfo-phenoxy)-benzene-1,3-disulfonic acid

 

The dissociation constants (pKa) of ditolylether disulfonic acid disodium salt, isomer mixture were estimated to be in a range of -0.61 to -0.10 for pKa1, in a range of -0.84 to -0.51 for pKa2 and in a range of -1.35 to -1.25 for pKa3.

The predicted values can be considered as reliable yielding a useful result for further assessment.

According to the estimated results, ditolylether disulfonic acid disodium salt, isomer mixture will be present mainly in deprotonated form under environmentally relevant pH 5-9.