Activation et désactivation de catalyseurs bimétalliques Pt-Sn/Al2O3 PDF Download

Author: Salah Eddine El Qebbaj
Publisher:
ISBN:
Category :
Languages : fr
Pages : 136

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Book Description
PAR DES EXPERIENCES IN-SITU EN ABSORPTION X, NOUS AVONS PU DETERMINER LES PARAMETRES STRUCTURAUX DE CATALYSEURS, PARAMETRES DIRECTEMENT ASSOCIES A LEURS PROPRIETES INTANSEQUES (ACTIVITE ET SELECTIVITE). L'ETUDE PAR LA TECHNIQUE EXAFS, AUX DEUX SEUILS L#I#I#I DU PLATINE ET K DE L'ETAIN, A PERMIS DE SUIVRE L'EVOLUTION DES SITES METALLIQUES LORS DES DIFFERENTS TRAITEMENTS SUBIS PAR LES CATALYSEURS PT-SN/AL#2O#3. AINSI NOUS AVONS PU MONTRER QUE LA REDUCTION DE CES MATERIAUX DONNE EN PREMIER DES AGREGATS DE PLATINE METALLIQUE, QUI FAVORISENT LA REDUCTION D'UNE PARTIE DE L'ETAIN. ENSUITE, L'ETAIN METALLIQUE AINSI FORME MIGRE SUR LE PLATINE ET INTERAGIT AVEC LUI POUR FORMER DES ALLIAGES DE COMPOSITION VARIABLE. CES ESPECES MIXTES PT-SN SONT EN GENERAL PEU STABLES LORSQU'ON SOUMET LES CATALYSEURS A DIFFERENTES ATMOSPHERES GAZEUSES

Author: Kah Sing Ho
Publisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 76

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Book Description
The problems faced in propane dehydrogenation, PDH process are lack of information on the commercially obtained Pt-Sn/Al2O3 catalyst and formation of coke. Therefore, this research deals with characterization of regenerated Pt-Sn/Al2O3 catalyst obtained from PDH plant and coke formation during propane dehydrogenation process at different temperature. Analyses of these characteristics were performed using nitrogen adsorption method, X-Ray Diffraction, Field Emission Scanning Electron Microscopy, X-Ray Photoelectron Spectroscopy and Fourier Transform Infrared Spectroscopy. Effect of temperatures on coke formation is identified by studying the fraction of products formed over the catalyst using Temperature Programmed Reaction. XPS was able to pick up traces of carbon in regenerated catalyst with percentage of atomic composition of 7.750%. FTIR had suggested that most of the carbon exist in the form of alkane and alkene where ethylene and methane records the highest fraction of side products formed by TPR. The regenerated Pt-Sn/Al2O3 catalyst has a surface area of 103.554 m2/g and mean pore radius of 12.695 nm with highest crystallite sizes of 20.0 nm. As for the effect of temperature towards coke formation, more carbon precursors were produced at higher temperature suggesting that more coke will be formed on the catalyst resulting in less propylene formed at higher temperatures. Spent catalyst yields a lower surface area of 78.943 m2/g and means pore radius of 10.151 nm compared to regenerated catalyst. Besides, the coke formed on the catalyst forms a crystal which was detected by XRD with its size of 25.7 nm. The increment of carbon content in the spent catalyst was traced by XPS where the percentage of atomic concentration increased to 31.75%.

Author: Gerhard Ertl
Publisher: John Wiley & Sons
ISBN: 3527620680
Category : Science
Languages : en
Pages : 639

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Book Description
Solid catalysts play a fundamental role in all areas between basic research and industrial applications. This book offers a large amount of information about the preparation of solid catalysts. All types of solid catalysts and all important aspects of their preparation are discussed. The highly topical contributions are written by leading experts in disciplines ranging from solid state, interface and solution chemistry to industrial engineering. The straightforward presentation of the material and the comprehensive coverage make this book an essential and indispensible tool for every scientist and engineer working with solid catalysts.

Author: M. Albert Vannice
Publisher: Springer Science & Business Media
ISBN: 0387259724
Category : Science
Languages : en
Pages : 257

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Book Description
Describes how to conduct kinetic experiments with heterogeneous catalysts, analyze and model the results, and characterize the catalysts Detailed analysis of mass transfer in liquid phase reactions involving porous catalysts. Important to the fine chemicals and pharmaceutical industries so it has appeal to many researchers in both industry and academia (chemical engineering and chemistry departments

Author: Junhua (Alex) Tao
Publisher: John Wiley & Sons
ISBN: 1118028295
Category : Technology & Engineering
Languages : en
Pages : 494

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Book Description
This book describes recent progress in enzyme-driven green syntheses of industrially important molecules. The first three introductory chapters overview recent technological advances in enzymes and cell-based transformations, and green chemistry metrics for synthetic efficiency. The remaining chapters are directed to case studies in biotechnological production of pharmaceuticals (small molecules, natural products and biologics), flavors, fragrance and cosmetics, fine chemicals, value-added chemicals from glucose and biomass, and polymeric materials. The book is aimed to facilitate the industrial applications of this powerful and emerging green technology, and catalyze the advancement of the technology itself.

Author: Horst Surburg
Publisher: John Wiley & Sons
ISBN: 3527693181
Category : Science
Languages : en
Pages : 392

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Book Description
This 6th edition is thoroughly revised and updated, and now additionally includes all commercially important flavor and fragrance materials that entered the market over the past 10 years. In one handy and up-to-date source, this classic reference surveys those natural and synthetic materials that are commercially available, produced, and used on a relatively large scale, covering their properties, manufacturing methods employed, and areas of application. For this new edition the chapter on essential oils has been completely revised with regard to production volumes, availability, and new product specifications, while new legal issues, such as REACH regulation aspects, are now included. Finally, the CAS registry numbers and physicochemical data of over 350 single substances and 100 essential oils have been updated and revised.

Author: Carl Frey
Publisher:
ISBN:
Category : Cooking
Languages : en
Pages : 240

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Book Description
With the development of synthetic organic chemistry techniques in the early 19th century the world of synthetic F&F materials began and expanded, but it has not totally replaced natural F&F. A growing segment of the public prefers natural foods to foods containing artificial additives, and will pay a premium for natural foods. While modern synthetic methods permit the economical production of artificial F&F on a large scale, the natural F&F industry remains important. Why is this so? How do the chemical, biological, and agricultural sciences support the natural F&F industry? What is the state of current natural F&F research? These are questions this volume attempts to address. Even considering only the value of F&F derived from essential oils, natural F&F constitute approximately a $2 billion annual business. The impact of F&F is best appreciated when you consider that a flavor or fragrance typically contributes only a very small part, both in cost and volume, to a finished product. Many analytical tools available do not have a detector that is as sensitive to taste or odor as a human (or many animals for that matter). The challenge for researchers is to sift F&F information from all the data obtained from the various analytical techniques. The intent of this book is to give the reader and appreciation for the many facets of the chemistry, analysis and production of natural flavors and fragrances. It is a field where each one of us who can smell and taste are active participants. New foods, plants, processes, packages and aromas are developed each day. Keeping researchers abreast of the many new facets of the natural F&F field have led to development of this chapter and the ACS symposium that served as the basis of this book.