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]  inTENSIDE, SURFACTANTS, DETERGENTS > Vol. 48, N° 1/2010 (01-02/2011) . - p. 73-81 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 Saccharose Index. 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 [article]

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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)

[article]  inTENSIDE, SURFACTANTS, DETERGENTS > Vol. 47, N° 2/2010 (03-04/2010) . - p. 98-105 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 [article]

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Experimental techniques to examine the degree of cure in UV-curable coating technology / Vipin Shukla in PAINTINDIA, Vol. LV, N° 2 (02/2005)

[article]  inPAINTINDIA > Vol. LV, N° 2 (02/2005) . - p. 49-50 Titre : Experimental techniques to examine the degree of cure in UV-curable coating technology Type de document : texte imprimé Auteurs : Vipin Shukla, Auteur ; M. Singh, Auteur ; R. Shukla, Auteur ; D. K. Singh, Auteur Année de publication : 2005 Article en page(s) : p. 49-50 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 667.9 Revêtements et enduits Résumé : This paper is an attempt to freeze momentarily in time a continuously and rapidly changing field of study which, to say the least, is highly complex. Even the descriptive terminology pertaining to this type of investigation is mercurial, ranging from physiochemical to chemorheological to the even more abtuse designation, chemoprocessing . To put the reader at ease with the subject, a short historical introduction is therefore in order. The uv-curing of epoxyacrylate resin systems involves photochemical processes . Thus an understanding of their chemical and physical characteristics before ,during, and after processing is prerequisite to their successful application. Note de contenu : - Different epoxy acrylate resins - Characterization techniques - Thermogravimetric analysis - Infra-red spectroscopy - Finger-tip test - Solvent rub test - Cotton test - Permanganate stain test - Pencil hardness Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=11956 [article]

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Studies on phenol novolac modified hybrid powder coating / Vipin Shukla in PAINTINDIA, Vol. LIV, N° 6 (06/2004)

[article]  inPAINTINDIA > Vol. LIV, N° 6 (06/2004) . - p. 61-63 Titre : Studies on phenol novolac modified hybrid powder coating Type de document : texte imprimé Auteurs : Vipin Shukla, Auteur ; D. K. Singh, Auteur ; M. Singh, Auteur ; Ravi Shukla, Auteur Année de publication : 2004 Article en page(s) : p. 61-63 Note générale : Bibliogr. Langues : Anglais (eng) Résumé : This paper provides thoughts and ideas for using phenol novolac resin in hybrid powder coatings either in pure form or modified form. Matt and glossy finish powder coating compositions were prepared with and without novolac resin the performance of novolac resin in hybrid (epoxy-polyester) powder coating was observed through several physical and chemical properties like gloss, flexibility, impact, adhesion solvent resistance, salt spray test etc. Note de contenu : - Synthesis of novolac resin - Synthesis of epoxy resin - Determination of epoxide equivalent weight (EEW) Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12018 [article]

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The role of castor oil in epoxy and polyamide systems for coating and adhesive application / V. Shukla in SURFACE COATINGS INTERNATIONAL. PART B : COATINGS TRANSACTIONS, Vol. 88, B3 (09/2005)  

[article]  inSURFACE COATINGS INTERNATIONAL. PART B : COATINGS TRANSACTIONS > Vol. 88, B3 (09/2005) . - p. 217-220 Titre : The role of castor oil in epoxy and polyamide systems for coating and adhesive application Type de document : texte imprimé Auteurs : V. Shukla, Auteur ; M. Singh, Auteur ; D. K. Singh, Auteur ; Ri. Shukla, Auteur Année de publication : 2005 Article en page(s) : p. 217-220 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Adhésion Alliages polymères Brillance (optique) Epoxydes Essais dynamiques Huile de ricin et constituants Polyamides Un polyamide est un polymère contenant des fonctions amides -C(=O)-NH- résultant d'une réaction de polycondensation entre les fonctions acide carboxylique et amine. Selon la composition de leur chaîne squelettique, les polyamides sont classés en aliphatiques, semi-aromatiques et aromatiques. Selon le type d'unités répétitives, les polyamides peuvent être des homopolymères ou des copolymères. Polyamines Résistance chimique Réticulants Souplesse (mécanique) Index. décimale : 667.9 Revêtements et enduits Résumé : Over the past few years, the challenges of globalisation, consolidation and economical point of view have meant that manufacturers of epoxy formulations have to constantly improve their capability to meet the needs of customers. An active area for advancement is that of epoxy and polyamide resin with castor oil. Generally, people working in the coating industries are familiar with castor oil, but this paper provides information on the new use of castor oil in epoxy and polyamide resin. This novel product (castor oil-modified epoxy resin/castor oil-modified polyamide) provides a previously unattainable combination and improved flexibility and toughness to a variety of ambient cure applications. This communication will review the performance of these castor oil-modified epoxy and polyamide resin surface coatings and adhesives. Based on the results of this study, these systems offer some advantages without much affecting the traditional properties of epoxy and polyamide resin in a variety of applications. Note de contenu : - EXPERIMENTAL : Materials - Methods - RESULTS AND DISCUSSION : Flexibility - Impact test - Adhesion - Gloss - Chemical resistance DOI : 10.1007/BF02699576 En ligne : https://link.springer.com/content/pdf/10.1007/BF02699576.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=5419 [article]

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