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Biologically Active Tin Compounds Based on Aziridine and Azepane Derivatives / H. El-sharkawy Ali in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 45, N° 2/2008 (03-04/2008)
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Titre : Biologically Active Tin Compounds Based on Aziridine and Azepane Derivatives Type de document : texte imprimé Auteurs : H. El-sharkawy Ali, Auteur Année de publication : 2008 Article en page(s) : p. 76-80 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Nitrogen heterocycles Aziridine Azepane derivatives Critical micelle concentration Surface tension Antimicrobial activity Surfactants Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : Four of new tin(IV) compounds derived from aziridine and azepane substituents have been synthesized and characterization by elemental microanalysis, atomic absorption, FT-IR and 1H-NMR spectroscopy. These tin-derived compounds exhibited biocidal activities on four different microorganisms: Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus niger. The use of common and effective biocides depends on the surfactant molecules. On this basis, surface tension measurements were used to determine the critical micellar concentration (cmc), the minimum average area per surfactant molecule (Amin) and the surface excess concentration (L8). A direct relationship has found between the antimicrobial efficacy and L8. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3033
in TENSIDE, SURFACTANTS, DETERGENTS > Vol. 45, N° 2/2008 (03-04/2008) . - p. 76-80[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 009993 - Périodique Bibliothèque principale Documentaires Disponible Synthesis, characterization and thermodynamic parameters of anionic gemini surfactants with different spacer groups / H. El-sharkawy Ali in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 44, N° 5/2007 (10-11/2007)
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Titre : Synthesis, characterization and thermodynamic parameters of anionic gemini surfactants with different spacer groups Type de document : texte imprimé Auteurs : H. El-sharkawy Ali, Auteur Année de publication : 2007 Article en page(s) : p. 281-286 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adsorption
Caractérisation
Micelles
Surfactants -- Synthèse
Tension superficielle
ThermodynamiqueTags : 'Gemini surfactants' 'Critical micelle concentration' 'Surface tension kinetic micellization' 'Thermodynamics of Adsorption Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The aim of this work is to investigate the micellization and adsorption thermodynamics (DmicH°, DmicG°, DmicS°, DadsH°, DadsG°, DadsS°) for three novel anionic Gemini surfactants with the same structure except the spacer length of the polymethylene chain have been synthesized based on nonylphenol (NP). The surface tension at cmc (Ycmc) and critical micelle concentration (cmc) of the surfactants in aqueous solutions have been investigated. C20 values (surfactant concentration in the solution phase that will reduce the surface tension of the solvent by 20 mNm–1) were also obtained. The critical micellar concentration (cmc) and the minimum average area per surfactant molecule (Amin) at the air-water interface of Gemini surfactant decrease with increasing number of methylene moieties in the spacer and, consequently, with the enhanced hydrophilic character of the molecule. The results were discussed with particular emphasis on the effect of the length spacer on the hydrophilic character of the spacer group. The surface studies of the molecules confirm that the exothermic values of the differential enthalpy of micellization (DmicH°) decrease as the methylene moieties are lengthened. Moreover, the values of the free energy (DmicG°) and entropy (DmicS°) of micellization indicate an entropy driven phenomenon for all surfactants. The effect of length spacer on surfactant adsorption for Gemini surfactants was utilized to calculate such thermodynamic parameters as the free energy of adsorption (DadsG°) and the heat of adsorption (DadsH°). The low value of DadsH° is an evidence for the physical adsorption of anionic surfactants. The relatively large value of entropic contribution (TDadsS°) indicates that the adsorption of anionic surfactants is entropically governed. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3204
in TENSIDE, SURFACTANTS, DETERGENTS > Vol. 44, N° 5/2007 (10-11/2007) . - p. 281-286[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 008403 - Périodique Bibliothèque principale Documentaires Disponible