Benzenesulfonic acid, methyl-, C20-24 (even numbered) sec-alkyl derivs.

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 September - 16 November 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source

Remarks:

Measurement of the test substance was not possible and therefore calculation using the EPIWIN and ACS labs modelling software was used

Qualifier:

according to guideline

Guideline:

OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)

Version / remarks:

Due to surface active properties, the partition coefficient couldn't be determined experimentally

Deviations:

not applicable

Principles of method if other than guideline:

also QSAR modeling was applied.

GLP compliance:

yes

Type of method:

slow-stirring method

Remarks:

The substance could not be determined experimentally and therefore a calculation using EPIWIN and ACS labs modelling software was carried out

Partition coefficient type:

octanol-water

Specific details on test material used for the study:

- Analytical purity: 94.55 %
- Expiration date: 31 December 2017
- Storage condition: at room temperature

Key result

Type:

log Pow

Partition coefficient:

>= 9.3 - <= 13.6

Remarks on result:

other: calculated value obtained from EPIWIN and ACS labs modelling software

Details on results:

The test substance was not detected in the aqueous layer on all the sampling occasions, even when the aqueous layer was injected neat. The concentration in the octanol layer gave recoveries of 60 to 100 %. The appearance of the octanol layer also varied from sampling point to sampling point from the appearance of two layers through cloudy to a clear brown solution.
The aqueous solubility would suggest that the test substance would be detectable in the aqueous layer. It might be concluded that the surface activity of the test substance would be having an effect on the partitioning between the two layers and the variability of the recoveries in the octanol. Vigorously shaking a flask containing octanol with test substance at 45,000 µg/mL and pH4 buffer gave as might be expected for a surface active material, three layers.
It is therefore concluded that the partition coefficient cannot be practically measured and a calculated value for the Log Pow was generated using EPIWIN and ACD labs modelling software.

Calculation of the LogPow using EPIWIN and ACD labs modelling software:

Structure	EPIWIN	ACD labs
C20	9.26	11.49 +-0.20
C24	11.22	13.61 +-0.20

Conclusions:

The LogPow of the test substance was calculated to be 9.3 to 13.6.

Description of key information

The partition coefficient (logPow) of the test substance could not be determined experimentally by Foster (2016) using the slow stirring method (OECD 123). Therefore, the partition coefficient was determined using EPIWIN and ACS lab models. From these calculations (K2) it could be concluded that the logPow of the test substance ranges from 9.3 to 13.6.