Supported and Unsupported Palladium Nanoparticles for Heterogeneous Catalysis

Supported and Unsupported Palladium Nanoparticles for Heterogeneous Catalysis PDF Author: Renee Wai Ying Man
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Supported and Unsupported Palladium Nanoparticles for Heterogeneous Catalysis

Supported and Unsupported Palladium Nanoparticles for Heterogeneous Catalysis PDF Author: Renee Wai Ying Man
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Model Systems in Catalysis

Model Systems in Catalysis PDF Author: Robert Rioux
Publisher: Springer Science & Business Media
ISBN: 0387980490
Category : Science
Languages : en
Pages : 531

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Book Description
This book is an excellent compilation of cutting-edge research in heterogeneous catalysis and related disciplines – surface science, organometallic catalysis, and enzymatic catalysis. In 23 chapters by noted experts, the volume demonstrates varied approaches using model systems and their successes in understanding aspects of heterogeneous catalysis, both metal- and metal oxide-based catalysis in extended single crystal and nanostructured catalytic materials. To truly appreciate the astounding advances of modern heterogeneous catalysis, let us first consider the subject from a historical perspective. Heterogeneous catalysis had its beginnings in England and France with the work of scientists such as Humphrey Davy (1778–1829), Michael Faraday (1791–1867), and Paul Sabatier (1854–1941). Sabatier postulated that surface compounds, si- lar to those familiar in bulk to chemists, were the intermediate species leading to catalytic products. Sabatier proposed, for example, that NiH moieties on a Ni sur- 2 face were able to hydrogenate ethylene, whereas NiH was not. In the USA, Irving Langmuir concluded just the opposite, namely, that chemisorbed surface species are chemically bound to surfaces and are unlike known molecules. These chemisorbed species were the active participants in catalysis. The equilibrium between gas-phase molecules and adsorbed chemisorbed species (yielding an adsorption isotherm) produced a monolayer by simple site-filling kinetics.

Unsupported Thiolate-capped Palladium Nanoparticles as Selective Hydrogenation Catalysts

Unsupported Thiolate-capped Palladium Nanoparticles as Selective Hydrogenation Catalysts PDF Author: Jie S. Zhu
Publisher:
ISBN: 9781085564441
Category : Alkenes
Languages : en
Pages : 45

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Abstract: The reactions of palladium are invaluable to modern academic and industrial research, and nanotechnology is the foundation on which the next generation of materials is built upon. Unsupported thiolate-capped palladium nanoparticles were found to be highly substrate selective for alkene hydrogenation and isomerization. A modified Brust-Schiffrin reaction enabled the facile and convenient synthesis of a diverse set of ultra-small thiolate-capped nanoparticles. The physical properties of these nanoparticles were highly tunable due to the widespread availability of ligand precursors. Mechanistic evidence and insights reveal that steric and electronic effects from the ligand environment on the nanoparticle surface controlled reactivity by influencing alkene adsorption via [pi] bond coordination or di-[sigma] bond formation. Only alkenes close enough to the metal surface of the nanoparticles underwent reaction. Dienes with good overlapping p orbitals could overcome these steric effects on the deactivated palladium nanoparticle surfaces. A mechanistic model was built from these completed studies, and this model can be used to predict the selectivity of hydrogenation or isomerization in multiple classes of alkenes with varied substitution patterns. These palladium nanoparticles were also found to be capable of chemoselective alkene hydrogenation in the presence of functional groups that are known to be labile towards reduction by palladium.

Palladium-Catalyzed Coupling Reactions

Palladium-Catalyzed Coupling Reactions PDF Author: Árpád Molnár
Publisher: John Wiley & Sons
ISBN: 3527648305
Category : Science
Languages : en
Pages : 531

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Book Description
This handbook and ready reference brings together all significant issues of practical importance in selected topics discussing recent significant achievements for interested readers in one single volume. While covering homogeneous and heterogeneous catalysis, the text is unique in focusing on such important aspects as using different reaction media, microwave techniques or catalyst recycling. It also provides a comprehensive treatment of key issues of modern-day coupling reactions having emerged and matured in recent years and emphasizes those topics that show potential for future development, such as continuous flow systems, water as a reaction medium, and catalyst immobilization, among others. With its inclusion of large-scale applications in the pharmaceutical industry, this will equally be of great interest to industrial chemists. From the contents * Palladium-Catalyzed Cross-Coupling Reactions - A General Introduction * High-turnover Heterogeneous Palladium Catalysts in Coupling Reactions: the Case of Pd Loaded on Dealuminated Y Zeolites Palladium-Catalyzed Coupling Reactions with Magnetically Separable Nanocatalysts * The Use of Ordered Porous Solids as Support Materials in Palladium-Catalyzed Cross-Coupling Reactions * Coupling Reactions Induced by Polymer-Supported Catalysts * Coupling Reactions in Ionic Liquids * Cross-Coupling Reactions in Aqueous Media * Microwave-Assisted Synthesis in C-C and C-Heteroatom Coupling Reactions * Catalyst Recycling in Palladium-Catalyzed Carbon-Carbon Coupling Reactions * Nature of the True Catalytic Species in Carbon-Carbon Coupling Reactions with * Heterogeneous Palladium Precatalysts * Coupling Reactions in Continuous Flow Systems * Large-Scale Applications of Palladium-Catalyzed Couplings in the Pharmaceutical Industry

Preparation of Catalysts VII

Preparation of Catalysts VII PDF Author: R. Maggi
Publisher: Elsevier
ISBN: 0080539459
Category : Technology & Engineering
Languages : en
Pages : 1007

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Book Description
The proceedings of the VIIth International Symposium on the Scientific Bases for the Preparation of Heterogeneous Catalysts, are in line with the general scope of this series of events. Emphasis in all Symposia has been on the scientific aspects of the preparation of new and industrial catalysts, or on new methods of preparation, rather than on the catalytic reactions in which such solids are ultimately used. In the present context, the catalytic event itself has only been considered as another, though often decisive, method of catalyst characterization.

New Trends in Cross-Coupling

New Trends in Cross-Coupling PDF Author: Thomas Colacot
Publisher: Royal Society of Chemistry
ISBN: 1849738963
Category : Science
Languages : en
Pages : 914

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Book Description
Following on from its recognition in the 2010 Nobel Prize for Chemistry, contributors from across the globe present the latest cross-coupling trends in both academia and industry.

Catalysis

Catalysis PDF Author: James J Spivey
Publisher: Royal Society of Chemistry
ISBN: 184755329X
Category : Technology & Engineering
Languages : en
Pages : 361

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Book Description
There is an increasing challenge for chemical industry and research institutions to find cost-efficient and environmentally sound methods of converting natural resources into fuels chemicals and energy. Catalysts are essential to these processes and the Catalysis Specialist Periodical Report series serves to highlight major developments in this area. This series provides systematic and detailed reviews of topics of interest to scientists and engineers in the catalysis field. The coverage includes all major areas of heterogeneous and homogeneous catalysis and also specific applications of catalysis such as NOx control kinetics and experimental techniques such as microcalorimetry. Each chapter is compiled by recognised experts within their specialist fields and provides a summary of the current literature. This series will be of interest to all those in academia and industry who need an up-to-date critical analysis and summary of catalysis research and applications. Catalysis will be of interest to anyone working in academia and industry that needs an up-to-date critical analysis and summary of catalysis research and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading experts in their specialist fields, this series is designed to help the chemistry community keep current with the latest developments in their field. Each volume in the series is published either annually or biennially and is a superb reference point for researchers. www.rsc.org/spr

The Synthesis of Solid Supported Palladium Nanoparticles

The Synthesis of Solid Supported Palladium Nanoparticles PDF Author: Kendra W. Brinkley
Publisher:
ISBN:
Category : Carbon nanotubes
Languages : en
Pages : 272

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Book Description
Catalysis is one of the pillars of the chemical industry. While the use of catalyst is typically recognized in the automobile industry, their impact is more widespread as; catalysts are used in the synthesis of 80% of the US commercial chemicals. Despite the improved selectivity provided by catalyst, process inefficiencies still threaten the sustainability of a number of synthesis methods, especially in the pharmaceutical industry. Recyclable solid supported catalysts offer a unique opportunity to address these inefficiencies. Such systems coupled with continuous synthesis techniques, have the potential to significantly reduce the waste to desired product ratio (E-factor) of the production techniques. This research focuses developing sustainable processes to synthesize organic molecules by using continuous synthesis methods. In doing so, solid supported metal catalyst systems were identified, developed, and implemented to assist in the formation of carbon-carbon bonds. Newly developed systems, which utilized metal nanoparticles, showed reactivity and recyclability, comparable to commercially available catalyst. Nanoparticles are emerging as useful materials in a wide variety of applications including catalysis. These applications include pharmaceutical processes by which complex and useful organic molecules can be prepared. As such, an effective and scalable synthesis method is required for the preparation of nanoparticle catalysts with significant control of the particle size, uniform dispersion, and even distribution of nanoparticles when deposited on the surface of a solid support. This project describes the production of palladium nanoparticles on a variety of solid supports and the evaluation of these nanoparticles for cross coupling reactions. This report highlights novel synthesis techniques used in the formation of palladium nanoparticles using traditional batch reactions. The procedures developed for the batch formation of palladium nanoparticles on different solid supports, such as graphene and carbon nanotubes, are initially described. The major drawbacks of these methods are discussed, including limited scalability, variation of nanoparticle characteristics from batch to batch, and technical challenges associated with efficient heating of samples. Furthermore, the necessary conditions and critical parameters to convert the batch synthesis of solid supported palladium nanoparticles to a continuous flow process are presented. This strategy not only alleviates the challenges associated with the robust preparation of the material and the limitations of scalability, but also showcases a new continuous reactor capable of efficient and direct heating of the reaction mixture under microwave irradiation. This strategy was further used in the synthesis of zinc oxide nanoparticles. Particles synthesized using this strategy as well as traditional synthesis methods, were evaluated in the context industrially relevant applications.

New and Future Developments in Catalysis

New and Future Developments in Catalysis PDF Author: P. Štěpnička
Publisher: Elsevier Inc. Chapters
ISBN: 0128081864
Category : Science
Languages : en
Pages : 62

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Liquid Phase Oxidation via Heterogeneous Catalysis

Liquid Phase Oxidation via Heterogeneous Catalysis PDF Author: Mario G. Clerici
Publisher: John Wiley & Sons
ISBN: 1118356756
Category : Science
Languages : en
Pages : 438

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Book Description
Sets the stage for environmentally friendly industrial organic syntheses From basic principles to new and emerging industrial applications, this book offers comprehensive coverage of heterogeneous liquid-phase selective oxidation catalysis. It fully examines the synthesis, characterization, and application of catalytic materials for environmentally friendly organic syntheses. Readers will find coverage of all the important classes of catalysts, with an emphasis on their stability and reusability. Liquid Phase Oxidation via Heterogeneous Catalysis features contributions from an international team of leading chemists representing both industry and academia. The book begins with a chapter on environmentally benign oxidants and then covers: Selective oxidations catalyzed by TS-1 and other metal-substituted zeolites Selective catalytic oxidation over ordered nanoporous metallo-aluminophosphates Selective oxidations catalyzed by mesoporous metal-silicates Liquid phase oxidation of organic compounds by supported metal-based catalysts Selective liquid phase oxidations in the presence of supported polyoxometalates Selective oxidations catalyzed by supported metal complexes Liquid phase oxidation of organic compounds by metal-organic frameworks Heterogeneous photocatalysis for selective oxidations with molecular oxygen All the chapters dedicated to specific types of catalysts follow a similar organization and structure, making it easy to compare the advantages and disadvantages of different catalysts. The final chapter examines the latest industrial applications, such as the production of catechol and hydroquinone, cyclohexanone oxime, and propylene oxide. With its unique focus on liquid phase heterogeneous oxidation catalysis, this book enables researchers in organic synthesis and oxidation catalysis to explore and develop promising new catalytic materials and synthetic routes for a broad range of industrial applications.