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Physical & Chemical properties

Partition coefficient

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Description of key information

A log Kow of 5.4 has been reported in a thesis (Artola-Garicano 2002) where the slow stirring method has been used. A more formal partition coefficient determination on the basis of HPLC has been measured by a GLP compliant laboratory using OECD method 117. The value obtained from the slow-stirring method has been leading in the EU Risk Assessment Report of AHTN (May 2008).

Key value for chemical safety assessment

Log Kow (Log Pow):
5.4
at the temperature of:
25 °C

Additional information

A log Kow of 5.4 was selected for the environmental risk assessment in the EU Risk Assessment Report of AHTN (EU RAR). However, for the purpose of REACH, the underlying source was a thesis from a doctoral student without any raw data. The EU RAR did not substantiate this particular log Kow selection. The log Kow is an important parameter and the reported value is not regarded as sufficiently reliable without a supporting study. Hence a supporting study has been included in the AHTN registration, which is a reversed phase HPLC experiment (Rudio 1993). The partition coefficients from Artola and Rudio differ 0.3 log units, which is even within the range of the repeatability of the shake-flask method. On that basis, a log Kow of 5.4 is acceptable and selected on the basis of consistency with the EU RAR.