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Surface tension

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Description of key information

The surface tension of Alcohols, C9-11-linear and branched is read across from the measured values for the pure linear constituents. At 90% saturated aqueous solution the constituents have measured surface tension values of ca. 18-36 mN/m based on a reliable and well-reported published study.

Key value for chemical safety assessment

Additional information

The main purpose of determining surface tension is to assess whether a substance is a surfactant and not able to have a log Kow done. The close structural analogue n-octanol is regularly used with water in the classic two-phase partitioning experiment (e.g. OECD Guideline 107). Octanol and all alcohols do phase separate which suggests that emulsification is not so strong as to create issues with measurement of partitioning or other fate or effects studies. The reported measurements, for highly pure samples of nonan-1-ol, decan-1-ol and undecan-1-ol are at ca. 90% aqueous solution based on the limit of solubility of highly pure alcohols as reported in the literature.

Discussion of trends in the Category of C6-24 linear and essentially-linear aliphatic alcohols:

Chemical derivatives of many of the alcohols in this group are products which have commercial uses relating to their properties as surface active agents. The alcohols themselves are not surface active. Whilst the preliminary assessment by Hydrophilic Lipophilic Balance (HLB) suggests that the shortest chain members of the Category (C6 - C8) could be water/oil emulsifiers, this should not be over-interpreted. They are co-surfactants used to modify the properties of other surfactants.

Above C8 there is no alert based on HLB for any surface tension lowering property.