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Bicontinuous microemulsion as reaction medium for ω-transaminase catalysed biotransformations / M. Laupheimer in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 48, N° 1/2010 (01-02/2011)
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Titre : Bicontinuous microemulsion as reaction medium for ω-transaminase catalysed biotransformations Type de document : texte imprimé Auteurs : M. Laupheimer, Auteur ; S. Engelskirchen, Auteur ; K. Tauber, Auteur ; W. Kroutil, Auteur ; C. Stubenrauch, Auteur Année de publication : 2011 Article en page(s) : p. 28-33 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Aminoacyltransférases
Biotransformation (métabolisme)
Catalyse enzymatique
Microémulsions
Réactions chimiquesTags : 'Microémulsion bi-continue' Métabolisation 'Réaction enzymatique' 'Incompatibilité enzyme/substrat' de milieu' Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : Due to their high enantioselectivity biotransformations, i.e. enzyme-catalysed conversion of organic compounds, are extremely attractive reactions. However, a limiting factor for choosing substrates is the enzyme-substrate incompatibility. This occurs when a hydrophilic enzyme which naturally resides in the aqueous cell cytoplasm is supposed to convert a hydrophobic substrate. In this context bicontinuous microemulsions appear to be a beneficial reaction medium for biotransformations, particularly due to their large interfacial area between a hydrophilic and a hydrophobic compound. As a "proof of concept" we performed ω-transaminase (EC 2.6.1.18) catalysed model reactions in a bicontinuous microemulsion of the type phosphate buffer/NaCl – n-octane – pentaethylene glycol monodecyl ether. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10667
in TENSIDE, SURFACTANTS, DETERGENTS > Vol. 48, N° 1/2010 (01-02/2011) . - p. 28-33[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 012778 - Périodique Bibliothèque principale Documentaires Disponible Colloid and interfacial chemistry at Stuttgart University / R. Baum in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 48, N° 3/2011 (05/2011)
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Titre : Colloid and interfacial chemistry at Stuttgart University : an overview of past, current, and planned research activities Type de document : texte imprimé Auteurs : R. Baum, Auteur ; J. Boos, Auteur ; E. Carey, Auteur ; G. Catanoiu, Auteur ; S. Engelskirchen, Auteur ; B. Feucht, Auteur ; M. Laupheimer, Auteur ; J. Porada, Auteur ; F. Schüler, Auteur ; L. Szymanski, Auteur ; D. Zauser, Auteur ; C. Stubenrauch, Auteur Année de publication : 2011 Article en page(s) : p. 250-255 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chimie des surfaces
Colloides
Couches minces
Inositol
Microémulsions
Mousse (chimie)
Nanostructures
Surfactants
Systèmes auto-assemblésIndex. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The research work carried out in our group can be referred to as “Colloid and Interfacial Chemistry”. We subdivide this rather broad research area into four main topics which are covered by the projects presented in this overview. The surfaces we study are surfactant-loaden water-air surfaces, the films are mainly free-standing thin foam films of less than 100 nm thickness, and the foams are 3D aqueous foams whose stability and drainage we investigate. As regards the topic “Complex Fluids” we study lyotropic liquid crystalline phases and microemulsions. In the past, we were able to establish two new tuning parameters for the formation and destruction of lyotropic liquid crystals, while current research focuses on the lyotropic mesomorphism of new surfactants and of surfactant mixtures. Apart from lyotropic liquid crystals microemulsions are a central theme in the group. Due to their unique properties and fascinating structure variety microemulsions offer a great potential as templates for the synthesis of new functional materials, which is a further research topic in our group. These studies involve the gelation of and the polymerisation in microemulsions preserving their nanostructure to create high surface area polymers. Currently, we also use microemulsions as tailor-made nano-compartmented reaction media. The studied reactions are either enzyme-catalysed conversions of substrates or the reduction of metal salts to synthesize mono- or bimetallic nanoparticles. In this context we focus on bicontinuous and water-in-oil droplet microemulsions. Last but not least we also synthesize new surfactant structures such as inositol-based surfactants and explore the properties. Note de contenu : - Surfaces, films, foams
- Gelled microemulsions as orthogonal self-assembled systems and templates for novel materials
- Reactions in nanostructured self-assembled systems
- Design of new inositol-based surfactants : structure-property relationsPermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11707
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Code-barres Cote Support Localisation Section Disponibilité 012974 - Périodique Bibliothèque principale Documentaires Disponible Conductivity measurements as a method for studying ionic technical grade surfactants / E. Carey in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 45, N° 3/2008 (05-06/2008)
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Titre : Conductivity measurements as a method for studying ionic technical grade surfactants Type de document : texte imprimé Auteurs : E. Carey, Auteur ; C. Stubenrauch, Auteur ; S. R. Patil, Auteur Année de publication : 2008 Article en page(s) : p. 120-125 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Conductivité ionique
Micelles
Surfactants
Tensions (chimie)Tags : Ionic technical grade surfactant Specific conductivity Surface tension Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The critical micellar concentrations (cmc) of cationic alkyltrimethylammonium bromides (C10TAB–C16TAB) and of anionic alkyl sulfates (SDS, technical grade Sulfopon 12G and Sulfopon 1214G) were determined using specific conductivity and surface tension measurements. While the cationic surfactants were purified, the anionic surfactants were used as received. In the former case, surface tension and conductivity measurements lead to the same cmc values. In the latter case, measuring the specific conductivities (bulk property) proved to be superior compared to measuring the surface tensions (surface property) because the presence of highly surface active impurities creates a pronounced minimum in the surface tension isotherm, which makes it impossible to determine an accurate value for the cmc. On the other hand, these impurities do not influence the conductivities, i.e. that the conductivities can be used to determine cmc values of impure and technical grade ionic surfactants, respectively. Moreover, an evaluation of the specific conductivities allows for the determination of the degree of micelle ionization (alpha) of the ionic surfactant solutions and thus provides additional useful information. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3044
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Code-barres Cote Support Localisation Section Disponibilité 010305 - Périodique Bibliothèque principale Documentaires Disponible Interfacial tensions, partition coefficients, and interfacial eelasticities : measures for emulsion stability ? / N. Buchavzov in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 44, N° 4/2007 (08-09/2007)
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Titre : Interfacial tensions, partition coefficients, and interfacial eelasticities : measures for emulsion stability ? Type de document : texte imprimé Auteurs : N. Buchavzov, Auteur ; F. Ravera, Auteur ; S. Hess, Auteur ; Y. Liu, Auteur ; U. Steinbrenner, Auteur ; C. Stubenrauch, Auteur Année de publication : 2007 Article en page(s) : p. 230-238 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Coefficient de partage (chimie)
Emulsions -- Stabilité
Rhéologie
Tension superficielleIndex. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : In this study the interfacial as well as the surface tensions, the partition coefficients Kp, the interfacial elasticities, and the stabilities of o/w-emulsions of the same systems were measured and compared to find a quantitative correlation which can help to control the emulsion stability. The systems in question contain water, paraffin oil and one of four non-ionic technical surfactants commonly used as emulsifiers. While a clear correlation between emulsion stability and equilibrium interfacial tension was found, the different emulsifying capacities cannot be explained by the partition coefficients Kp or the surface tension. However, combining the Kp results with the surface tension data allows us to estimate which emulsifier is more effective in solubilising a given amount of dispersed phase. Another method to classify emulsifiers is to carry out interfacial rheology measurements over a frequency range as broad as possible. Again a clear correlation between interfacial rheology and emulsifying capacity was found. This correlation, however, was restricted to surfactants of the same class. No correlation between interfacial rheology and emulsifying capacity could be found for emulsifiers of different molecular structure. DOI : 10.3139/113.100344 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3211
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Code-barres Cote Support Localisation Section Disponibilité 008233 - Périodique Bibliothèque principale Documentaires Disponible