Registration Dossier

Diss Factsheets

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

In accordance with Section 2 of Annex XI of Regulation (EC) 1907/2006 (REACH), it is considered justified to omit the test for partition coefficient (required under point 7.8 of Annex VII) as it is considered that testing is not technically possible.
No experimental determination of partition coefficient was feasible due to the test material being a complex UVCB substance. The shake flask method is poorly suited to complex mixtures and in addition is not considered valid for surface active substances (surface tension value determined to be 44.0 to 44.4 mN/m). Experimental determination of the partition coefficient range of the test item was attempted by the HPLC estimation method in accordance with the standardised guidelines OECD 117 and EU Method A.8; however a suitable method of detection could not be obtained.
Assessments were performed using evaporative light scattering, refractive index and mass selective detectors. In each case, no significant response was obtained for the test material. 

Key value for chemical safety assessment

Log Kow (Log Pow):
4.22

Additional information

Supporting information is provided in the form of an estimation produced by validated estimation software. The estimation was performed on representative structures of the test material.

Sufficient information is available to evaluate the applicability of the model, EPI Suite v4.1: KOWWIN v1.68 from the US Environmental Protection Agency, to these structures. It was assigned a reliability score of 2 in accordance with the criteria detailed by Klimisch (1997).

The partition coefficient of a number of proposed representative test material component structures were estimated. The estimations were performed using a fragment constant methodology applied by the specialised predictive software KOWWIN v1.68 (September 2010), © 2000 U.S. Environmental Protection Agency. Estimations were performed for both the molecular forms of the parent acids and the relevant salts.

The log10 Pow values of the molecular forms of the representative structures ranged from 3.76 to 12.5. The log10 Pow values of the salted forms of the representative structures ranged from -0.05 to 8.64. The figure for the structure considered to be the most representative was 4.22.

The USA EPA HPV document mentions a log10 Kow range of 3.8 to 6.0.