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Environmental fate & pathways

Adsorption / desorption

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Description of key information

The soil adsorption coefficient of the registered substance was determined via read across to the results of testing on the structurally similar substance tosyl salt. The Log Koc of the acid component of the substance was found to be <1.3 at 25°C.

Key value for chemical safety assessment

Koc at 20 °C:
20

Additional information

The soil adsorption coefficient of the registered substance was determined via read-across to the results of testing on a structurally similar substance (tosyl salt). The tosyl salt was tested in accordance with the OECD Guideline for Testing of Chemicals 121. The HPLC method was used to determine the log Kocvalue for the acid and amine components of the test substance. As the test substance contains ionisable components, the test was performed at pH 4, 7 and 9, covering the pH range of environmental release. This is in accordance with the requirements of the OECD Testing Guideline (121), which states that for ionisable substances both the ionised and non-ionised forms should be tested. Based on the dissociation constants of the acid and amine components of the test substance (previously determined via an experimental study and detailed in Section 4.2.1 of the IUCLID) this pH range ensures that the soil adsorption study took account of the ionised and non-ionised form. The acid component of the test substance was found to have log10Kocvalues of 2, <1.3 and <1.3 at pH 4, 7 and 9 respectively. The amine component of the test substance was found to have log10Kocvalues of 3.2, 2.4 and 2.2 at pH 4, 7 and 9, respectively. Read-across between the registered substance and the test substance (tosyl salt) is considered justified owing to the structural similarity of the two substances. Both are salts of a carboxylic acid and triethanolamine. The acid components are structural isomers and differ only in the position of a single methyl group in the N-methyl salt. This is not expected to change the behavior or properties of the substances, and both substances have shown similarity in the results of other physical endpoints such as water solubility.

[LogKoc: 1.3]