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Oxidation of chloride ion on platinum electrode / Rajkumar S. Patil in Industrial & engineering chemistry research, Vol. 50 N° 23 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12946–12959 Titre : Oxidation of chloride ion on platinum electrode : dynamics of electrode passivation and its effect on oxidation kinetics Type de document : texte imprimé Auteurs : Rajkumar S. Patil, Auteur ; Vinay A. Juvekar, Auteur ; Vijay M. Naik, Auteur Année de publication : 2012 Article en page(s) : pp. 12946–12959 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxidation  Ion  Kinetics Résumé : Kinetics of oxidation of chloride ion is studied on both active platinum electrode and that undergoing transient passivation. Experiments are conducted in concentrated NaCl solution at rotating disk electrode. It is observed that on the active platinum electrode, oxidation is very fast, and hence the current density is controlled by the ohmic resistance of the solution. Electrode kinetics becomes important only when the electrode is passivated to a significant extent. Kinetics of chloride oxidation on the electrode undergoing passivation is modeled using the Butler–Volmer equation, in which the contribution from the ohmic resistance of the solution is incorporated. Two regimes of passivation are identified. The first is the fast regime corresponding to the formation of the platinum oxide monolayer. In this regime, the rate of passivation is first order in the concentration of the metal sites on the surface. In the slow passivation regime, the exchange current density for chloride oxidation is found to vary inversely with square root of time. This regime is modeled by considering unsteady diffusion of oxygen ions through the metal lattice. From this analysis it is concluded that the chloride oxidation current is almost totally contributed by a small fraction of the active metal sites which are continuously being regenerated as a result of diffusion of oxygen ions from the surface into the bulk of the metal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200663a [article] Oxidation of chloride ion on platinum electrode : dynamics of electrode passivation and its effect on oxidation kinetics [texte imprimé] / Rajkumar S. Patil, Auteur ; Vinay A. Juvekar, Auteur ; Vijay M. Naik, Auteur . - 2012 . - pp. 12946–12959. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 23 (Décembre 2011) . - pp. 12946–12959 Mots-clés : Oxidation  Ion  Kinetics Résumé : Kinetics of oxidation of chloride ion is studied on both active platinum electrode and that undergoing transient passivation. Experiments are conducted in concentrated NaCl solution at rotating disk electrode. It is observed that on the active platinum electrode, oxidation is very fast, and hence the current density is controlled by the ohmic resistance of the solution. Electrode kinetics becomes important only when the electrode is passivated to a significant extent. Kinetics of chloride oxidation on the electrode undergoing passivation is modeled using the Butler–Volmer equation, in which the contribution from the ohmic resistance of the solution is incorporated. Two regimes of passivation are identified. The first is the fast regime corresponding to the formation of the platinum oxide monolayer. In this regime, the rate of passivation is first order in the concentration of the metal sites on the surface. In the slow passivation regime, the exchange current density for chloride oxidation is found to vary inversely with square root of time. This regime is modeled by considering unsteady diffusion of oxygen ions through the metal lattice. From this analysis it is concluded that the chloride oxidation current is almost totally contributed by a small fraction of the active metal sites which are continuously being regenerated as a result of diffusion of oxygen ions from the surface into the bulk of the metal. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie200663a

Soap / Janhavi S. Raut in Industrial & engineering chemistry research, Vol. 47 N°17 (Septembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°17 (Septembre 2008) . - p. 6347–6353 Titre : Soap : the polymorphic genie of hierarchically structured soft condensed-matter products Type de document : texte imprimé Auteurs : Janhavi S. Raut, Auteur ; Vijay M. Naik, Auteur Année de publication : 2008 Article en page(s) : p. 6347–6353 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Metal  salts  Fatty  acids  Soaps Résumé : More than 5 million tonnes of metal salts of fatty acids are manufactured and used worldwide every year, to create a range of soft condensed-matter products such as bar soaps, stick deodorants, personal care creams, toothpastes, and lubricant greases. These molecules, popularly known as soaps, are capable of forming a plethora of states and self-assembled aggregates such as micelles, liquid crystals, solid crystals, and gels, whose characteristic sizes or domain sizes can span from nanometers to centimeters. The type and mix of the phases formed, their morphologies, and their states of dispersion or the nature of their further supra-assemblies dictate the underlying micromechanical structures of products, which, in turn, are responsible for their optical, structural, and rheological properties. Developing processing guidelines to manipulate characteristic micromechanical structures is therefore key to obtaining the desired look, touch, feel, and function of these products. The article discusses a few illustrative examples of these structure−property relationships demonstrated by multiscale soap assemblies. Observations of some novel tertiary structures formed by crystallizing soap fibers at the air−water interface, serendipitously discovered by us in the recent past, are also discussed, to illustrate the richness and mysteries of the well-studied and so-called mature subject of soaps. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714753 [article] Soap : the polymorphic genie of hierarchically structured soft condensed-matter products [texte imprimé] / Janhavi S. Raut, Auteur ; Vijay M. Naik, Auteur . - 2008 . - p. 6347–6353. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°17 (Septembre 2008) . - p. 6347–6353 Mots-clés : Metal  salts  Fatty  acids  Soaps Résumé : More than 5 million tonnes of metal salts of fatty acids are manufactured and used worldwide every year, to create a range of soft condensed-matter products such as bar soaps, stick deodorants, personal care creams, toothpastes, and lubricant greases. These molecules, popularly known as soaps, are capable of forming a plethora of states and self-assembled aggregates such as micelles, liquid crystals, solid crystals, and gels, whose characteristic sizes or domain sizes can span from nanometers to centimeters. The type and mix of the phases formed, their morphologies, and their states of dispersion or the nature of their further supra-assemblies dictate the underlying micromechanical structures of products, which, in turn, are responsible for their optical, structural, and rheological properties. Developing processing guidelines to manipulate characteristic micromechanical structures is therefore key to obtaining the desired look, touch, feel, and function of these products. The article discusses a few illustrative examples of these structure−property relationships demonstrated by multiscale soap assemblies. Observations of some novel tertiary structures formed by crystallizing soap fibers at the air−water interface, serendipitously discovered by us in the recent past, are also discussed, to illustrate the richness and mysteries of the well-studied and so-called mature subject of soaps. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714753