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An efficient and mild procedure for the preparation of aldonic acids via oxidation of D-sucrose by employing N-bromophthalimide oxidant and micellar system / Y. Katre in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 48, N° 1/2010 (01-02/2011)
[article]
Titre : An efficient and mild procedure for the preparation of aldonic acids via oxidation of D-sucrose by employing N-bromophthalimide oxidant and micellar system Type de document : texte imprimé Auteurs : Y. Katre, Auteur ; M. Singh, Auteur ; A. K. Singh, Auteur Année de publication : 2011 Article en page(s) : p. 73-81 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Catalyse
Cinétique chimique
Concentration micellaire critique
Micelles
SaccharoseIndex. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The oxidation reactions of D-sucrose have been carried out with N-bromophthalimide in the presence of micellar aggregates at 45°C. The kinetics revealed first order dependence on N-bromophthalimide (NBP) and fractional order dependence on D-sucrose. Variation of mercuric acetate concentration has an insignificant effect on reaction rate. The stoichiometric ratio of NBP:D-sucrose was 1:2 and the oxidation product was aldonic acid confirmed by FeCl3–HCl test. The influence of salts on the reaction rate has also been studied. Phthalimide (NHP) and sulfuric acid (H2SO4) inhibit the rate. Thermodynamic and activation parameters have been evaluated and a mechanism consistent with the kinetic data has been proposed. Cetyltrimethylammonium bromide (CTAB) and TritonX-100 (TX-100) catalyze the reaction, while sodium dodecyl sulfate (SDS) inhibits the rate of reaction. The applicability of Berezin's model was tested to explain the observed micellar effects. The rate constants (kM) and binding constants (KS + KO) have been evaluated. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10677
in TENSIDE, SURFACTANTS, DETERGENTS > Vol. 48, N° 1/2010 (01-02/2011) . - p. 73-81[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 012778 - Périodique Bibliothèque principale Documentaires Disponible Effect of cetyltrimethylammonium bromide on the oxidation of béta-alanine by N-bromophthalimide in acidic medium / Y. R. Katre in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 45, N° 4/2008 (07-08/2008)
[article]
Titre : Effect of cetyltrimethylammonium bromide on the oxidation of béta-alanine by N-bromophthalimide in acidic medium Type de document : texte imprimé Auteurs : Y. R. Katre, Auteur ; G. K. Joshi, Auteur ; A. K. Singh, Auteur Année de publication : 2008 Article en page(s) : p. 213-221 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Kinetics Oxidation B-alanine Binding constant Index cooperativity Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The kinetics of the oxidation of béta-alanine (Ala) by N-bromophthalimide (NBP) has been studied in the presence of cationic surfactant, cetyltrimethylammonium bromide (CTAB) at 313 K. The oxidation kinetics exhibits first order kinetics with respect to [Oxidant], fractional order of [Ala] and inverse fractional order of [H+] on the rate of reaction. The rate of reaction decreases with decreasing dielectric constant of the medium. The rate constant increases with increasing CTAB and then constant. Increasing [Hg(OAc)2] and inorganic salts i.e. [Cl–] and [Br–] increased the rate of reaction, whereas a change in ionic strength of the medium had no effect on oxidation velocity. Methyl Cyanide as the main oxidation product has been identified. Thermodynamic and activation parameters have been evaluated. The rate constants, binding constants with surfactant (CTAB) and the index of cooperativity have also been evaluated. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2947
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Code-barres Cote Support Localisation Section Disponibilité 010535 - Périodique Bibliothèque principale Documentaires Disponible Effect of micellar aggregates on the kinetics of dextrose oxidation by N-bromosuccinimide / Y. Katre in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 47, N° 2/2010 (03-04/2010)
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Titre : Effect of micellar aggregates on the kinetics of dextrose oxidation by N-bromosuccinimide Type de document : texte imprimé Auteurs : Y. Katre, Auteur ; A. K. Singh, Auteur ; M. Singh, Auteur Année de publication : 2010 Article en page(s) : p. 98-105 Note générale : Bibliogr. Langues : Anglais (eng) Tags : Catalyse micellaire Oxydation Cinétique Concentration critique (CMC) Réactions bimoléculaires Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The kinetics of oxidation of dextrose by N-bromosuccinimide (NBS) has been investigated in the presence of cationic cetyltrimethylammonium bromide (CTAB) surfactant in sulfuric acid (H2SO4) medium. Similarly in absence of CTAB solution, the reaction followed fractional, first, and negative fractional-order kinetics with respect to [dextrose], [NBS] and [H2SO4], respectively. Although the reaction mechanism remained unaltered by micelles, a typical kpsi-[CTAB] profile was observed, that is, with a progressive increase in [CTAB], the reaction rate increased, reached a maximum value, and then decreased. The results are treated quantitatively in terms of Berezin's model. Activation parameters were also evaluated and a negative value of deltaS# shows the formation of well-structured activated complex. The influence of salts on the reaction rates has also been seen. On the basis of product analysis, a pertinent mechanism is proposed. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8878
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Code-barres Cote Support Localisation Section Disponibilité 012052 - Périodique Bibliothèque principale Documentaires Disponible Kinetic and mechanistic study of the influence of micelles on the oxidation of acetone by N-bromophthalimide in aqueous acetic acid medium / Y. R. Katre in TENSIDE, SURFACTANTS, DETERGENTS, Vol. 46, N° 4/2009 (07-8/2009)
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Titre : Kinetic and mechanistic study of the influence of micelles on the oxidation of acetone by N-bromophthalimide in aqueous acetic acid medium Type de document : texte imprimé Auteurs : Y. R. Katre, Auteur ; K. Tripathi, Auteur ; G. K. Joshi, Auteur ; A. K. Singh, Auteur Année de publication : 2009 Article en page(s) : p. 218-227 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Surfactants Tags : N-bromophthalimide Cetyltrimethylammonium bromide Sodium dodecyl sulphate Acetone Oxidation Kinetics Index. décimale : 668.1 Agents tensioactifs : savons, détergents Résumé : The effect of cationic micelles of Cetyltrimethylammonium bromide (CTAB) and anionic micelles of Sodium dodecyl Sulphate (SDS) on the kinetics of oxidation of acetone by N-Bromophthalimide (NBP) was studied iodometrically at 308 K. In addition to kinetic experiments, conductivity measurements have also been done to obtain critical micelle concentration and other thermodynamic properties. The kinetic observations indicate fractional order and first order dependence, with respect to [Acetone] and [NBP] respectively. Cationic surfactant (CTAB) strongly catalysed the oxidation of acetone in aqueous acetic acid medium and typical kobs and [CTAB] profile was observed i.e. with the progressive increase in [CTAB], the reaction rate increased, at higher concentration constancy in kobs was observed, whereas anionic surfactant (SDS) was found to show no considerable effect on reaction rate. Mercuric acetate and phthalimide exhibited nil effect on the reaction rate. The presence of inorganic salts (KCl, KBr) exhibits positive effect in the reaction rate. The various activation parameters in presence of CTAB and SDS have been also evaluated. A suitable mechanism consistent with the experimental findings has been proposed. The binding constant with surfactants has been evaluated. DOI : 10.3139/113.110027 Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=6055
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Code-barres Cote Support Localisation Section Disponibilité 011484 - Périodique Bibliothèque principale Documentaires Disponible Transfer efficiency for airless painting systems / Michael W. Plesniak in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 1, N° 2 (04/2004)
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Titre : Transfer efficiency for airless painting systems Type de document : texte imprimé Auteurs : Michael W. Plesniak, Auteur ; A. K. Singh, Auteur ; Paul E. Sojka, Auteur Année de publication : 2004 Article en page(s) : p. 137-145 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Dépôt par pulvérisation
Latex
Peinture au pistolet
Revêtements en phase aqueuse:Peinture en phase aqueuseIndex. décimale : 667.9 Revêtements et enduits Résumé : Spray transfer efficiency (TE) is defined as the mass fraction of sprayed paint which is deposited on the intended target, the remainder of the sprayed paint becomes undesirable overspray. The relationship between TE and gun supply pressure (or paint mass flow rate), gun-to-target distance, gun traverse speed, the angle of the spray gun relative to the target (gun-to-target angle), plus spray cone angle is reported herein for a typical fan spray system. Experimental results indicate that spray momentum rate (SMR) and droplet size dictate the TE for the various combinations of parameters considered here. The key finding is that TE correlates with SMR and spray mean drop size (Sauter mean diameter or D32) via an expression of the form TE = a + b SMR - c (SMR)2 + d D32, where a, b, c, and d are coefficients determined by fitting the experimental data, and SMR is estimated via SMR = m 2 /pA, where the paint mass flow rate m , the paint density is p, and the gun exit orifice effective tip cross sectional area is A. This expression accounts for physical phenomena that govern sprayed droplet deposition characteristics, such as entrainment, bounce-back, and drop size. Experimental results also show that, for the range of parameters studied, gun traverse speed has no effect on TE, but increasing the angle of the spray gun relative to the target (gun-to-target angle), increasing the spray cone angle, or increasing the gun-to-target distance will decrease TE. DOI : 10.1007/s11998-004-0008-0 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-004-0008-0.pdf Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3959
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Code-barres Cote Support Localisation Section Disponibilité 000586 - Périodique Bibliothèque principale Documentaires Disponible Validation of a HPLC method for simultaneous determination of five sunscreens in lotion preparation / E. R. M. Kedor-Hackmann in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 28, N° 3 (06/2006)
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