In Situ NMR Methods in Catalysis

In Situ NMR Methods in Catalysis PDF Author: Joachim Bargon
Publisher: Springer Science & Business Media
ISBN: 354071426X
Category : Science
Languages : en
Pages : 179

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Book Description
Achemist,facedwiththeproblemofdeterminingthemechanismofachemical reaction, tries to identify a set of reactions that will account for the observed behavior:Ideally,asmallsetofknownreactionsshoulddescribeingreatdetail exactly what takes place at each stage of a chemical transformation. The fact that many reactions proceed in a stepwise fashion can most convincingly be demonstrated if intermediate species can be isolated and shown to proceed to the same products under otherwise identical reaction conditions. An - termediate is the reaction product of each of these steps, except for the last onethatformsthe?nalproduct. Someintermediatesarestablecompoundsin theirownright;someothers,however,aresoreactivethattheirisolationisnot possible. Occasionally, evidence for the existence of short-lived intermediates may be obtained, in particular by spectroscopic observation. The latter may - low a direct observation or an indirect inference from unusual phenomena occurring in the reaction products during in situ investigations of their c- responding chemical reactions. In NMR spectroscopy, for example, transient emissionandenhanced absorptionlinesmaybeobserved, andoneisinclined to believe that there is a universal and unambiguous reason for their appe- ance. Thisisnotnecessarilythecase,however,sincethisseeminglyidentical phenomenon may have a strikingly different origin: During free radical re- tions,aphenomenoncalledchemicallyinduced dynamicnuclear polarization (CIDNP) may give rise to virtually the same effect as occasionally observed duringhomogeneous(andpossiblyevenheterogeneous)hydrogenations:The latter phenomenon, called parahydrogen-induced polarization (PHIP), has a completely different physical basis. It was ?rst noticed twenty years later than CIDNP and occurs if there is an imbalance of the two spin isomers of symmetric molecules such as dihydrogen when hydrogenating unsaturated compoundsusingappropriatecatalysts. Thesetwoeffects,ifnotdifferentiated properly, can cause misinterpretations of reaction mechanisms, as occurred initially when their different origins had not yet been understood approp- ately.

In Situ NMR Methods in Catalysis

In Situ NMR Methods in Catalysis PDF Author: Joachim Bargon
Publisher: Springer Science & Business Media
ISBN: 354071426X
Category : Science
Languages : en
Pages : 179

Get Book Here

Book Description
Achemist,facedwiththeproblemofdeterminingthemechanismofachemical reaction, tries to identify a set of reactions that will account for the observed behavior:Ideally,asmallsetofknownreactionsshoulddescribeingreatdetail exactly what takes place at each stage of a chemical transformation. The fact that many reactions proceed in a stepwise fashion can most convincingly be demonstrated if intermediate species can be isolated and shown to proceed to the same products under otherwise identical reaction conditions. An - termediate is the reaction product of each of these steps, except for the last onethatformsthe?nalproduct. Someintermediatesarestablecompoundsin theirownright;someothers,however,aresoreactivethattheirisolationisnot possible. Occasionally, evidence for the existence of short-lived intermediates may be obtained, in particular by spectroscopic observation. The latter may - low a direct observation or an indirect inference from unusual phenomena occurring in the reaction products during in situ investigations of their c- responding chemical reactions. In NMR spectroscopy, for example, transient emissionandenhanced absorptionlinesmaybeobserved, andoneisinclined to believe that there is a universal and unambiguous reason for their appe- ance. Thisisnotnecessarilythecase,however,sincethisseeminglyidentical phenomenon may have a strikingly different origin: During free radical re- tions,aphenomenoncalledchemicallyinduced dynamicnuclear polarization (CIDNP) may give rise to virtually the same effect as occasionally observed duringhomogeneous(andpossiblyevenheterogeneous)hydrogenations:The latter phenomenon, called parahydrogen-induced polarization (PHIP), has a completely different physical basis. It was ?rst noticed twenty years later than CIDNP and occurs if there is an imbalance of the two spin isomers of symmetric molecules such as dihydrogen when hydrogenating unsaturated compoundsusingappropriatecatalysts. Thesetwoeffects,ifnotdifferentiated properly, can cause misinterpretations of reaction mechanisms, as occurred initially when their different origins had not yet been understood approp- ately.

NMR Techniques in Catalysis

NMR Techniques in Catalysis PDF Author: Alexis T. Bell
Publisher: CRC Press
ISBN: 9780824791735
Category : Science
Languages : en
Pages : 450

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Book Description
This volume provides an overview of the applications of modern solid-state nuclear magnetic resonance (NMR) techniques to the study of catalysts, catalytic processes, species adsorbed on catalysts and systems relevant to heterogeneous catalysis. It characterizes the structure of catalytic materials and surfaces.

NMR and MRI of Electrochemical Energy Storage Materials and Devices

NMR and MRI of Electrochemical Energy Storage Materials and Devices PDF Author: Yong Yang
Publisher: Royal Society of Chemistry
ISBN: 1788018486
Category : Science
Languages : en
Pages : 573

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Book Description
The aim of this book is to introduce the use of NMR and MRI methods for investigating electrochemical storage materials and devices to help both NMR spectroscopists entering the field of batteries and battery specialists seeking diagnostic methods for material and device degradation.

Characterization of Heterogeneous Catalysts

Characterization of Heterogeneous Catalysts PDF Author: Francis Delannay
Publisher: Marcel Dekker
ISBN:
Category : Science
Languages : en
Pages : 432

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Book Description


NMR Techniques in Catalysis

NMR Techniques in Catalysis PDF Author: Alexis T. Bell
Publisher: CRC Press
ISBN: 1000105083
Category : Science
Languages : en
Pages : 447

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Book Description
This volume provides an overview of the applications of modern solid-state nuclear magnetic resonance (NMR) techniques to the study of catalysts, catalytic processes, species adsorbed on catalysts and systems relevant to heterogeneous catalysis. It characterizes the structure of catalytic materials and surfaces.

In-situ Spectroscopy in Heterogeneous Catalysis

In-situ Spectroscopy in Heterogeneous Catalysis PDF Author: James F. Haw
Publisher: Wiley-VCH Verlag GmbH
ISBN:
Category : Science
Languages : en
Pages : 296

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Book Description
"Not using in-situ methods to examine catalytic processes is like studying a life with access only to the prenatal and postmortem states." This quote from the world renowned specialist in the field of in situ methods, Gabor A. Somorjai, clearly emphasizes the importance of these techniques in understanding heterogeneous catalysis - a type of chemical reaction used nowadays for most chemically produced supplies and fuels. Yet the fundamental mechanisms are often still not completely understood. Many of the leading scientists in the field have contributed to this book which provides an overview of the most varied spectroscopic and related methods for studying catalytic structures and their functions during a chemical reaction. While primarily written for users of these methods, this is also a valuable aid to interpreting the phenomena observed. Indispensable for everyone working in the field.

In-situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis

In-situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis PDF Author: Shi-Gang Sun
Publisher: Elsevier
ISBN: 0080489060
Category : Science
Languages : en
Pages : 559

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Book Description
In-Situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis is a new reference on in-situ spectroscopic techniques/applications, fundamentals of electrocatalysis at molecule level, and progresses within electrochemical surface science. Presenting both essential background knowledge at graduate level and original research within the fields of spectroscopy, electrochemistry, and surface science. Featuring 15 chapters by prominent worldwide scholars, based on their recent progress in different aspects of in-situ spectroscopy studies, this book will appeal to a wide audience of scientists. In summary this book is highly suitable for graduates learning basic concepts and advanced applications of in-situ spectroscopy, electrocatalysis and electrode adsorptions.* Written by the most active scientists in the fields of spectroscopy, electrochemistry and surface science* Essential background knowledge for graduate students* A modern reference of cutting-edge scientific research

Solid-State NMR in Zeolite Catalysis

Solid-State NMR in Zeolite Catalysis PDF Author: Jun Xu
Publisher: Springer
ISBN: 9811369674
Category : Science
Languages : en
Pages : 267

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Book Description
Solid-State NMR Characterization of Heterogeneous Catalysts and Catalytic Reactions provides a comprehensive account of state-of-the-art solid-state NMR techniques and the application of these techniques in heterogeneous catalysts and related catalytic reactions. It includes an introduction to the basic theory of solid-state NMR and various frequently used techniques. Special emphasis is placed on characterizing the framework and pore structure, active site, guest-host interaction, and synthesis mechanisms of heterogeneous catalysts using multinuclear one- and two-dimensional solid-sate NMR spectroscopy. Additionally, various in-situ solid-state NMR techniques and their applications in investigation of the mechanism of industrially important catalytic reactions are also discussed. Both the fundamentals and the latest research results are covered, making the book suitable as a reference guide for both experienced researchers in and newcomers to this field. Feng Deng is a Professor at Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences.

Springer Handbook of Advanced Catalyst Characterization

Springer Handbook of Advanced Catalyst Characterization PDF Author: Israel E. Wachs
Publisher: Springer Nature
ISBN: 3031071255
Category : Technology & Engineering
Languages : en
Pages : 1109

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Book Description
Co-edited by world-renowned scientists in the field of catalysis, this book contains the cutting-edge in situ and operando spectroscopy characterization techniques operating under reaction conditions to determine a materials’ bulk, surface, and solution complex and their applications in the field of catalysis with emphasis on solid catalysts in powder form since such catalyst are relevant for industrial applications. The handbook covers from widely-used to cutting-edge techniques. The handbook is written for a broad audience of students and professionals who want to pursue the full capabilities available by the current state-of-the-art in characterization to fully understand how their catalysts really operate and guide the rational design of advanced catalysts. Individuals involved in catalysis research will be interested in this handbook because it contains a catalogue of cutting-edge methods employed in characterization of catalysts. These techniques find wide use in applications such as petroleum refining, chemical manufacture, natural gas conversion, pollution control, transportation, power generation, pharmaceuticals and food processing. fdsfds

Catalysis by Microporous Materials

Catalysis by Microporous Materials PDF Author: H.K. Beyer
Publisher: Elsevier
ISBN: 0080544673
Category : Technology & Engineering
Languages : en
Pages : 811

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Book Description
ZEOCAT '95 is the eleventh in the series of symposia devoted to special fields of zeolite chemistry. Six plenary lectures, forty oral and forty-two poster presentations were included in the program. The accepted papers cover every aspect of catalysis on microporous materials. A significant number of the contributions describe the synthesis, modification, instrumental and chemical characterisation of zeolites and other micro- and mesoporous materials. Catalytic reactions involve hydrocarbon cracking, nucleophilic aromatic substitution, methanol to hydrocarbon conversion, hydration of acetylene, various alkylation reactions, redox transformations, Claisen rearrangement, etc.