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Octanol-water partition coefficients of surfactants : slow stirring/surface tension method / D. J. Miller in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 47, N° 1/2010 (01-02/2010)
[article]
Titre : Octanol-water partition coefficients of surfactants : slow stirring/surface tension method Type de document : texte imprimé Auteurs : D. J. Miller, Auteur ; P. McWilliams, Auteur Année de publication : 2010 Article en page(s) : p. 28-33 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Log P Surface tension Bioaccumulation Anionic surfactant Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : A slow stirring method to measure log P values of water-soluble surfactants is described. Aqueous surfactant solution is equilibrated with octanol. A surface tension technique is used to determine the decrease in concentration in the aqueous phase. Interference from octanol, which is surface active, is prevented by evaporation and redissolution of the sample. For industrial surfactants this method gives a log P value that is effectively weighted according to the surface activity of the components. The test can be used to screen surfactants for a possible risk of bioaccumulation as it is generally accepted that substances with log P < 3 are unlikely to bioaccumulate. The apparent log P of an alkane sulfonate was 1.5 when a 1 g/L aqueous solution was equilibrated with an equal volume of octanol. Due to ion pair formation in the octanol phase the apparent log P decreased with concentration. As a result, the tendency to partition into octanol is likely to be less at environmentally relevant concentrations. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8067
in TENSIDE, SURFACTANTS, DETERGENTS > Vol. 47, N° 1/2010 (01-02/2010) . - p. 28-33[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 011905 - Périodique Bibliothèque principale Documentaires Disponible Noionic surfactants : octanol-water partition coefficients with the slow stirring/surface tension method / Dennis J. Miller in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 49, N° 2 (03-04/2012)
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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[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13761 - Périodique Bibliothèque principale Documentaires Disponible