[article]
| Titre : |
Noionic surfactants : octanol-water partition coefficients with the slow stirring/surface tension method |
| Type de document : |
texte imprimé |
| Auteurs : |
Dennis J. Miller, Auteur ; Phil McWilliams, Auteur |
| Année de publication : |
2012 |
| Article en page(s) : |
p. 124-128 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Surfactants
|
| Tags : |
LogP 'Tension surface' Bioaccumulation 'Surfactant non ionique' |
| Index. décimale : |
668.1 Agents tensioactifs : savons, détergents |
| Résumé : |
LogP values for several nonionic surfactants were measured by the slow stirring/surface tension method. Aqueous surfactant solution is equilibrated with octanol. A surface tension technique is used to determine the concentration in the aqueous phase. Interference from octanol, which is surface active, is prevented by evaporation and re-dissolution of the sample. The effect of initial concentration on the observed logP value is discussed. Above a certain concentration the amount of surfactant in the aqueous phase exceeds the critical micelle concentration (cmc). In this region logP appears to decrease markedly with initial concentration. Using a simple model, which includes the effect of octanol on the cmc, the apparent logP can be corrected for this micellisation effect. With a tristyrylphenol ethoxylate the concentrations in aqueous and octanol phases were determined by UV absorption, giving a logP value in good agreement with the surface tension method. For a series of commercial undecyl ethoxylates, the logP value was found to decrease with increasing length of the EO chain. Products with more than 4 EO have a logP less than 3, indicating that they are unlikely to bioaccumulate. |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13904 |
in TENSIDE, SURFACTANTS, DETERGENTS > Vol. 49, N° 2 (03-04/2012) . - p. 124-128
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