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Physical & Chemical properties

Partition coefficient

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Description of key information

Introduction
No determination was possible according to Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Methods 107 and/or 117 of the OECD Guidelines for Testing of Chemicals, due to the following reasons:
An assessment of the emulsification properties of the test item was carried out with the test item prepared in water saturated n-octanol and shaken with an equal amount of n-octanol saturated water. Observations after this test showed that the two immiscible phases emulsified easily; additionally, after 1 hour standing, there were still three layers visible, the middle layer being a white emulsion. It was therefore considered that as the test item also gave a positive surface-active result in the Surface Tension test (See Section 7), the test item can be considered to be surface-active. Surface-active items are not suitable for determination by the flask-shake method or the HPLC method.
Estimation using the ratio of the solubility of the test item in n-octanol and water would also be unreliable due to the possible self-aggregation properties shown by surface-active substances.

Key value for chemical safety assessment

Log Kow (Log Pow):
8.87
at the temperature of:
20 °C

Additional information

Introduction

No determination was possible according to Method A8 Partition Coefficient of Commission Regulation (EC) No 440/2008 of 30 May 2008 and Methods 107 and/or 117 of the OECD Guidelines for Testing of Chemicals, due to the following reasons:

  • An assessment of the emulsification properties of the test item was carried out with the test item prepared in water saturated n-octanol and shaken with an equal amount of n-octanol saturated water. Observations after this test showed that the two immiscible phases emulsified easily; additionally, after 1 hour standing, there were still three layers visible, the middle layer being a white emulsion. It was therefore considered that as the test item also gave a positive surface-active result in the Surface Tension test (See Section 7.6 Surface Tension Harlan Laboratories study number 41003463), the test item can be considered to be surface-active. Surface-active items are not suitable for determination by the flask-shake method or the HPLC method.
  • Estimation using the ratio of the solubility of the test item in n-octanol and water would also be unreliable due to the possible self-aggregation properties shown by surface-active substances.

Method

Therefore, the partition coefficient was estimated using the computer-based specialist estimation software, KOWWIN, version 1.67a (Sept 2008), © 2000 U.S. Environmental Protection Agency.

The substance was modelled without the zinc atom as the per EPIsuite recommendations.

Conclusion

Using a computer-based atom fragment contribution method, KOWWIN, version 1.67a, © 2000 US Environmental Protection Agency, the partition coefficient (log10 Pow) has been estimated 8.87.