Disodium oxybis[methylbenzenesulphonate]

Partition coefficient

Description of key information

QSAR determinations of the logarithmic octanol-water partition coefficient for ditolylether disulfonic acid disodium salt, isomer mixture were performed using the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.1. 
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 four representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture. As, based upon its pKa values, ditolylether disulfonic acid disodium salt, isomer mixture exists predominantly in its dissociated form under environmental relevant pHs, calculations were performed for the dissociated and the non-dissociated form. The log Kow of the dissociated form of ditolylether disulfonic acid disodium salt, isomer mixture was estimated to be in a range of -4.12 to -1.54. Calculations for the non-dissociated of form ditolylether disulfonic acid disodium salt, isomer mixture yield a log Kow range of -0.75 to 1.04. 

Key value for chemical safety assessment

Log Kow (Log Pow):

-1.54

Additional information

As no experimental data regarding the logarithmic octanol-water partition coefficient (log Kow) for ditolylether disulfonic acid disodium salt, isomer mixture are available, the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.1 was used for calculation.

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 four representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture.

The representative constituents are:

A) disodium 3-methyl-4-(3-methyl-4-sulfonato-phenoxy)-benzenesulfonate

B) disodium 2-methyl-4-(3-methyl-4-sulfonato-phenoxy)-benzenesulfonate

C) trisodium 2-methyl-4-(2-methyl-4-sulfonato-phenoxy)-benzene-1,3-disulfonate

D) trisodium 2-methyl-5-(3-methyl-4-sulfonato-phenoxy)-benzene-1,3-disulfonate

 

As, based upon its pKa values, ditolylether disulfonic acid disodium salt, isomer mixture exists predominantly in its dissociated form under environmental relevant pHs, the log Kow was estimated for the dissociated and non-dissociated form of the representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture.

For the dissociated form the log Kow was estimated to be in a range of -4.12 to -1.54.

In general, the program considers salts of the representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture as "ion pair" compounds and gives a corresponding estimate. This means, the estimate for the salts of the constituents of ditolylether disulfonic acid disodium salt, isomer mixture is an estimate for the dissociated corresponding acid.

In order to estimate the neutral form of the representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture, the corresponding acid was chosen for calculation, as estimation of a salt is not considered by the program.

For the non-dissociated form the log Kow was estimated to be in a range of -0.75 to 1.04.

The results for the representative constituents of ditolylether disulfonic acid disodium salt, isomer mixture fall within the applicability domain described above and the applied estimation rules appear appropriate.

Therefore the predicted values can be considered reliable yielding useful results for further assessment.