21 résultat(s) recherche sur le tag ''Réaction'

Bicontinuous microemulsion as reaction medium for ω-transaminase catalysed biotransformations / M. Laupheimer in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 48, N° 1/2010 (01-02/2011)

[article]  inTENSIDE, SURFACTANTS, DETERGENTS > Vol. 48, N° 1/2010 (01-02/2011) . - p. 28-33 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 chimiques Tags : '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 [article]

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Catalysis of the epoxy-carboxyl reaction / Werner J. Blank in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 74, N° 926 (03/2002)

[article]  inJOURNAL OF COATINGS TECHNOLOGY (JCT) > Vol. 74, N° 926 (03/2002) . - p. 33-41 Titre : Catalysis of the epoxy-carboxyl reaction Type de document : texte imprimé Auteurs : Werner J. Blank, Auteur ; Marie E. Picci, Auteur Année de publication : 2002 Article en page(s) : p. 33-41 Note générale : Bibliogr. Langues : Américain (ame) Tags : 'Etude  expérimentale'  'Mécanisme  réaction'  'Activité  catalytique'  comparative'  'Catalyse  basique'  'Réaction  'Durcissement  matière  plastique'  'Acrylate  copolymère'  'Méthacrylate  'Résine  époxyde' Index. décimale : 667.9 Revêtements et enduits Résumé : We have investigated the reactions of glycidyl ether, glycidyl ester, and other oxirane functional resins with carboxyl or anhydride functional compounds and polymers in the presence of a wide range of amine, phosphonium, and metal catalysts. We confirmed that both amine and phosphonium compounds can catalyze the reaction of epoxy groups with carboxyl and anhydride groups. There are certain deficiencies with these catalysts, such as a tendency to yellow and a reduction in stability at ambient or elevated temperatures. We also observed that many of the known amine catalysts contribute to poorer humidity resistance and exterior durability. Several metal salts were found to be effective catalysts, but they also contributed to a reduction in chemical resistance or they led to paint instability. We have discovered a group of metal chelates that overcome these problems and provide stable formulations in a single package that do not yellow during cure and that give improved resistance properties. The new catalysts have been evaluated in high-solids epoxy/carboxyl coatings, automotive clearcoats, and powder coatings. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5670 [article]

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Diamine-catalyzed urethane reaction of 1,3-propanediol with phenyl isocyanate / Jiancheng Wang in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 10, N° 6 (11/2013)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 10, N° 6 (11/2013) . - p. 859-864 Titre : Diamine-catalyzed urethane reaction of 1,3-propanediol with phenyl isocyanate Type de document : texte imprimé Auteurs : Jiancheng Wang, Auteur ; Yunqiao Ding, Auteur ; Shijie Wang, Auteur ; Pengfei Yang, Auteur Année de publication : 2013 Article en page(s) : p. 859-864 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Catalyse Diamine Une diamine est un type de polyamine contenant exactement deux groupes amine. Les diamines sont principalement utilisées comme monomères pour synthétiser des polyamides, des polyimides et des polyurées. La principale diamine produite est le 1,6-diaminohexane, précurseur du Nylon 6-6, suivie de l'éthylènediamine1. L'hydrazine (H2NNH2) n'est en général pas considérée comme une diamine puisque ce n'est ni une amine (pas de carbone), ni une dibase. Fourier, Spectroscopie infrarouge à transformée de Isocyanate de phényle Propanediol Réactions chimiques Urethanes Tags : 'FTIR  in  situ'  'Réaction  uréthane'  'Diamine  tertiaire'  'Activité  catalytique' Index. décimale : 667.9 Revêtements et enduits Résumé : The urethane reaction of 1,3-propanediol with phenyl isocyanate is monitored by means of in situ FTIR. 1,4-Diazabicyclo[2.2.2]octane (DABCO) and N,N,N?,N?-tetramethylethane-1,2-diamine (TMEDA) are used as catalysts. Reaction rates are calculated, and reaction kinetics are studied. Furthermore, Gaussian programs are used to calculate steric configuration and electronegativity of those two diamines. The electronegativity of TMEDA is greater than that of DABCO, but the steric hindrance of DABCO in nitrogen atom is smaller. Steric hindrance plays a more important part in reaction kinetics, which makes the reaction to be catalyzed by DABCO at a faster rate. Finally, activation energy, activation enthalpy, and activation entropy for the reaction are calculated, followed by the discussion of reaction mechanism. Note de contenu : - EXPERIMENTAL : Materials and instruments - Kinetics studies - Computation methods - RESULTS AND DISCUSSION : Kinetics for the urethane reaction - Theoretical analysis - Thermodynamic parameters DOI : 10.1007/s11998-013-9523-1 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-013-9523-1.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=19825 [article]

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The selectivity of isophorone diisocyanate in the urethane reaction / R. Lomoelder in PAINTINDIA, Vol. XLVIII, N° 11 (11/1998)

[article]  inPAINTINDIA > Vol. XLVIII, N° 11 (11/1998) . - p. 31-38 Titre : The selectivity of isophorone diisocyanate in the urethane reaction : Influence of temperature, catalysis and reaction partners Type de document : texte imprimé Auteurs : R. Lomoelder, Auteur ; F. Plogmann, Auteur ; P. Speier, Auteur Année de publication : 1998 Article en page(s) : p. 31-38 Note générale : Bibliogr. Langues : Anglais (eng) Tags : 'Polyuréthane'  'Diisocyanate  organique'  'Cyclohexane  dérivé'  Polyaddition  Diol  'Réaction  catalytique'  modèle'  'Activité  'Sélectivité  catalyseur'  Régiosélectivité  'Acide  Lewis'  'Métal  Composé'  'Base  'Amine  tertiaire'  'Effet  température'  'Etude  expérimentale'  comparative' Index. décimale : 667.9 Revêtements et enduits Résumé : The selectivity of isophorone diisocyanate (IPDI) in the urethane reaction demonstrates a strong dependence on temperature, catalyst type, and degrees of substitution of the reaction partner. It was possible to establish, by means of GC analysis of the monomer content, that dibutyltin dilaurate (DBTL) leads to the highest selectivity compared to the series of Sn, Zn, Bi, Fe, and amine catalysts. The ratio ofthe rate constant Γin the model reaction with 1-butanol at 20°C was increased from 5.5 in the uncatalyzed variant to 11.5 by catalysis with DBTL. The use of diazabicyclooctane succeeded in reversing the selectivity. The selectivity under DBTL catalysis dropped from 11.5 at 20°C to 6.5 at 100°C. The use of 2-butanol leads to a further increase in selectivity: Γ= 17 with DBTL catalysis at 20°C. By the resolution of all four monourethanes by GC analysis of the 1-butanol reaction, a significantly higher selectivity of trans IPDI was established: the ratio of secondary monourethane to primary monourethane with trans IPDI is higher by a factor of 2. A very good correlation between prepolymer synthesis and the model reactions was observed. Recommended optimal conditions for prepolymer synthesis based on IPDI are temperatures between 40°C to 60°C using DBTL catalysis. Note de contenu : - Selectivity of IPDI by application of various urethane catalysts - Influence of temperature on the selectivity of IPDI - Additional steric hindrance : 2-butanol - Back to the pratical : NCO prepolymers Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=13179 [article]

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Alternate chemistries for film formation / Manoj R. Nair in PAINTINDIA, Vol. L, N° 1 (01/2000)

[article]  inPAINTINDIA > Vol. L, N° 1 (01/2000) . - p. 35 -42 Titre : Alternate chemistries for film formation Type de document : texte imprimé Auteurs : Manoj R. Nair, Auteur ; V. C. Malshe, Auteur Année de publication : 2000 Article en page(s) : p. 35 -42 Langues : Anglais (eng) Tags : 'Matériau  revêtement'  Peinture  'Formation  film'  'Réaction  chimique'  'Mécanisme  réaction' Index. décimale : 667.9 Revêtements et enduits Résumé : Film formation plays a crucial role in the coating industry. The conventional methods used involves film formation by evaporation of solvent, chemical reaction or by coalescence. In the present paper an effort is made to search for new chemistries. The reference for this paper are organic reactions which were not earlier used and these reactions were selected based on some guidelines. An effort is also made in terms of applying it to coating field. This paper has tried to put forth new ideas which may or not be applicable in practice with hpes that a step has been taken in proper direction. The chemisties mentioned here are open for suggestions and modifications. Note de contenu : - Coventional curing chemistries - Guidelines for selection of a reaction for film formation - New reported reactions - Recommandations Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12673 [article]

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Biodegradable binders ans cross- linking agents from renewable resources / G. J. H. Buisman in SURFACE COATINGS INTERNATIONAL, Vol. 82, N° 3 (03/1999)

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Compatibility testing of colored cosmetics – A new tool for objective testing near infrared remission spectroscopy (NIR-RS) / M. Rohr in IFSCC MAGAZINE, Vol. 8, N° 1 (01-02-03/2005)

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Ethylene formation from methionine as a method to evaluate oxygen free radical scavenging and metal inactivation by cosmetics / J.-B. Galey in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 13, N° 2 (04/1991)  

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Investigating of synthesis parameters, kinetics and pilot plant of sodium sarcosinate / Masoumeh Hassanzadeh in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 49, N° 6 (11-12/2012)

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Stabilization of aluminium pigments in water-borne systems by paint resins / Bodo Müller in SURFACE COATINGS INTERNATIONAL, Vol. 80, N° 7 (07/1997)

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La coloration prend de nouveaux reflets / Caroline Chavigny in PARFUMS COSMETIQUES ACTUALITES, N° 159 (06-07/2001)

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Définitions et spécifications des mortiers pour maçonnerie / Association Française de Normalisation (Paris) / Saint-Denis La Plaine : Association Française de Normalisation (AFNOR) (2001)

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Effects of sparse long chain branching on the spinning stability of LLDPEs / M. J. Bortner in INTERNATIONAL POLYMER PROCESSING, Vol. XIX, N° 3 (09/2004)  

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Electrochemical resistance and degradation of fluorinated polyolefines / A. Pud in SURFACE COATINGS INTERNATIONAL, Vol. 81, N° 6 (06/98)

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Interfacial studies of crosslinked urethanes : part IV. Substrate effect on film formation in polyester waterborne polyurethanes / Marek W. Urban in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 71, N° 896 (09/1999)

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Model compound study for acrylic latex crosslinking reactions with cycloaliphatic epoxides / Shaobing Wu in JOURNAL OF COATINGS TECHNOLOGY (JCT), Vol. 69, N° 869 (06/1997)

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Perfomance of fire resistant sealant under live power and intense flame / Harpal Singh in PAINTINDIA, Vol. L, N° 6 (06/2000)

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La pyrolyse laser / Nathalie Herlin-Boime in L'ACTUALITE CHIMIQUE, N° 317 (03/2008)  

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Réactions à économie d'atome / Véronique Michelet in L'ACTUALITE CHIMIQUE, N° 311 (08-09/2007)  

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Solvolyse de déchets de composites époxyde-verre in MATERIAUX & TECHNIQUES, N° 1-2 (01-02/2002)

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Vestanat IPDI / Dirk Reichel in PAINTINDIA, ANNUAL 1999 (04/1998)

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