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Book Synopsis Selective Catalysis Utilizing Bifunctionalized MCM-41 Mesoporous Materials by :
Download or read book Selective Catalysis Utilizing Bifunctionalized MCM-41 Mesoporous Materials written by and published by . This book was released on 2005 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selective catalysis is a field that has been under intense investigation for the last 100 years. The most widely used method involves catalysts with stereochemical selectivity. In this type of catalysis, the catalyst controls which reactants will be transformed into the desired product. The secret to employing this type of catalysis, though, is to design the proper catalyst, which can be difficult. One may spend as much time developing the catalyst as spent separating the various products achieved. Another method of selective catalysis is now being explored. The method involves utilizing a multifunctional mesoporous silica catalyst with a gate-keeping capability. Properly functionalized mesoporous materials with well-defined pore morphology and surface properties can provide an ideal three-dimensional environment for anchoring various homogeneous catalysts. These materials can circumvent the multi-sited two-dimensional nature most heterogeneous systems have without adversely impacting the reactant diffusivity. These single-site nanostructured catalysts with ordered geometrical structure are advantageous in achieving high selectivity and reactivity. Mesoporous materials can be prepared to include pores lined homogeneously with tethered catalysts via co-condensation. Additionally, these materials can be reacted with another (RO)3SiZ̃ group by using the traditional grafting method; this group is anchored predominantly at the entrances to the pores rather than inside the pores. Thus, if these Z̃ groups are chosen properly, they can select certain molecules to enter the pores and be converted to products (Scheme 1). In such multifunctional catalysts, the selectivity depends on the discrimination of the gatekeeper. Gate-keeping MCM-41 materials are at the forefront of catalytic substances.
Book Synopsis Selective Catalysis Utilizing Bifunctionalized MCM-41 Mesoporous Materials by : Kasey Jean Strosahl
Download or read book Selective Catalysis Utilizing Bifunctionalized MCM-41 Mesoporous Materials written by Kasey Jean Strosahl and published by . This book was released on 2005 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique properties of bifunctionalized MCM-41 prove it to be a valuable tool in the catalytic field. The primary functional group (i.e. acid/base, metal center) enables the reaction to proceed as the typical homogeneous reaction would; however, the secondary group places restrictions upon the catalytic reaction. The secondary group acts as a gatekeeper, only allowing the appropriate reactants to diffuse into the material's mesopores. In this work, hydrophobic pentafluorophenyl groups are co-condensed as secondary groups onto the inner surface of the pores. These secondary groups increase the hydrophobicity of the mesopores. By utilizing an aqueous solvent, then, one can control which reactants diffuse into the pores to interact with the catalyst. Herein, a Sharpless-type reaction between an organic azide and a terminal acetylene is effectively catalyzed using a copper/pentafluorophenyl MCM-41 material. The reaction's success depends upon the solvent employed-water versus benzene; therefore, the reaction is an example of how one can manipulate a catalytic reaction's yield by varying the reactant/solvent properties. Another reaction scheme is described where a molecule containing both hydrophobic and hydrophilic tails can be forced into a certain conformation by the hydrophobic MCM -41 in an aqueous solution to produce a syn elimination to a cis olefin. This method allows one to control the regiochemistry of the catalytic reaction. Numerous other types of reactions, including stereospecific reactions, could also be catalyzed using this same idea if modified to correspond with the appropriate characteristics.
Book Synopsis Zeolites and Mesoporous Materials at the Dawn of the 21st Century by : A. Galarneau
Download or read book Zeolites and Mesoporous Materials at the Dawn of the 21st Century written by A. Galarneau and published by Elsevier. This book was released on 2001-08-13 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Zeolites and Mesporous Materials at the Dawn of the 21st Century Proceedings are the expression of the oral and poster communications which where presented during the 13th International Zeolite Conference (IZC). They are subdivided into 32 thematic sessions starting from the genesis of materials to their applications through their characterisation. The paper volume contains the full texts of the 5 plenary and 6 keynote lectures and informative summaries of 150 oral and 540 poster presentations. These contributions have been selected among the 903 submissions received from a total of 57 countries! In order to gather all the communications in a handy document, the full texts of oral and poster presentations are available in CD-ROM. Besides the fields of zeolite science always represented at IZC (synthesis, characterisation, catalysis, etc¿), some subjects strengthened their position (mesoporous materials, theory and modelling), new areas emerge (advanced materials, environmental and life sciences) and older ones regain interest (natural zeolites). The understanding and development of the unique properties of porous materials relies on a unique blend of multidisciplinary knowledge: material science, with the implication of organic and colloid chemistry, to prepare micro- and mesoporous materials, surface and adsorption science sustained by theory and modelling to understand the peculiar behaviour of molecules in confined systems, special branches of catalysis, physics, chemical engineering and life science to design novel applications. The gathering of these elements is at the basis of a fruitful and evolutionary zeolite science, as it is hopefully reflected by these proceedings.
Book Synopsis Nanoporous Materials III by : M. Jaroniec
Download or read book Nanoporous Materials III written by M. Jaroniec and published by Elsevier. This book was released on 2002-05-15 with total page 711 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoporous Materials III contains the invited lectures and peer-reviewed oral and poster contributions to be presented at the 3rd Conference on Nanoporous Materials, which will be hosted in Ottawa, Canada, June 2002. The work covers complementary approaches to and recent advances in the field of nanostructured materials with pore sizes larger than 1nm, such as periodic mesoporous molecular sieves M41S and FSM16 and related materials including clays, carbon molecular sieves, colloidal crystal templated organic and inorganic materials, porous polymers and sol gels. The broad range of topics covered in relation to the synthesis and characterization of ordered mesoporous materials are of great importance for advanced adsorption, catalytic and separation processes as well as the development of nanotechnology. The contents of this title are based on topics to be discussed by invited lecturers, which deal with periodic mesoporous organosilicas, stability and catalytic activity of aluminosilicate mesostructures, electron microscopy studies of ordered materials, imprinted polymers and highly porous metal-organic frameworks. The other contributions deal with tailoring the surface and structural properties of nanoporous materials, giving a detailed characterization as well as demonstrating their usefulness for advanced adsorption and catalytic applications.
Book Synopsis Clonal Propagation of Strap-leafed Vanda by Shoot-tip Culture by : Christopher Kheng Hoe Teo
Download or read book Clonal Propagation of Strap-leafed Vanda by Shoot-tip Culture written by Christopher Kheng Hoe Teo and published by . This book was released on 1973 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Morphological Control of Multifunctionalized Mesoporous Silica Nanomaterials for Catalysis Applications by : Seong Huh
Download or read book Morphological Control of Multifunctionalized Mesoporous Silica Nanomaterials for Catalysis Applications written by Seong Huh and published by . This book was released on 2004 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu2 adsorption capacity tests. The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst system that is capable of activating two different substrates in aldol reaction, Henry reaction and cyanosilylation. One catalytic group activates the nucleophile, another organic group simultaneously activates the electrophile to enhance the total reaction rate. I systematically varied the amount of two organic groups and performed the three model reactions to compare rate enhancements.
Book Synopsis Mesoporous Zeolites by : Javier García-Martínez
Download or read book Mesoporous Zeolites written by Javier García-Martínez and published by John Wiley & Sons. This book was released on 2015-05-26 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Authored by a top-level team of both academic and industrial researchers in the field, this is an up-to-date review of mesoporous zeolites. The leading experts cover novel preparation methods that allow for a purpose-oriented fine-tuning of zeolite properties, as well as the related materials, discussing the specific characterization methods and the applications in close relation to each individual preparation approach. The result is a self-contained treatment of the different classes of mesoporous zeolites. With its academic insights and practical relevance this is a comprehensive handbook for researchers in the field and related areas, as well as for developers from the chemical industry.
Book Synopsis Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications by :
Download or read book Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications written by and published by . This book was released on 2004 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu2+ adsorption capacity tests, The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst system that is capable of activating two different substrates in aldol reaction, Henry reaction and cyanosilylation. One catalytic group activates the nucleophile, another organic group simultaneously activates the electrophile to enhance the total reaction rate. I systematically vaned the amount of two organic groups and performed the three model reactions to compare rate enhancements.
Book Synopsis Synthesis, Modification, and Application of Mesoporous Materials Based on MCM-41 by : Zeid Abdullah AL-Othman
Download or read book Synthesis, Modification, and Application of Mesoporous Materials Based on MCM-41 written by Zeid Abdullah AL-Othman and published by . This book was released on 2006 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: Findings and conclusions. The synthesized mesoporous materials possess high surface areas, large pore sizes, narrow pore size distributions, and high thermal, hydrothermal, and mechanical stabilities. The modified mesoporous materials were found to have high selectivity and capacity in the adsorption and separation of the transition and heavy metal ions in the aqueous solution. In addition, they showed great selectivity and capacity for the adsorption and separation of the radioactive materials in aqueous medium.
Book Synopsis Heterogeneous Catalysis and Fine Chemicals IV by : H.U. Blaser
Download or read book Heterogeneous Catalysis and Fine Chemicals IV written by H.U. Blaser and published by Elsevier. This book was released on 1997-06-19 with total page 693 pages. Available in PDF, EPUB and Kindle. Book excerpt: After three meetings in Poitiers, France, the 4th International Symposium on Heterogeneous Catalysis and Fine Chemicals was held under the auspices of the New Swiss Chemical Society in Basel, Switzerland. Fundamental as well as applied contributions on the use of heterogeneous catalysis for the preparation of fine chemicals were presented and discussed. The program consisted of 4 plenary lectures, 28 oral contributions and around 90 posters covering a broad range of reactions and catalytic aspects. 82 of these contributions are collected in the present proceedings, grouped into the following 8 topical areas: - Industrial and engineering problems (7 contributions) - Alkylation and acylation reactions (11 contributions) - Enantio- and diastereoselective hydrogenation reactions (9 contributions) - Chemoselective hydrogenation reactions (12 contributions) - Oxidation reactions (14 contributions) - Immobilized and encapsulated complex catalysts (12 contributions) - Zeolite and clay catalysts (12 contributions) - Miscellaneous topics (5 contributions)
Download or read book Nanocasting written by An-Hui Lu and published by Royal Society of Chemistry. This book was released on 2010 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructured materials with tailored properties are regarded as a fundamental element in the development of future science and technology. Research is still ongoing into the nanosized construction elements required to create functional solids. The recently developed technique, nanocasting, has great advantage over others in terms of the synthesis of special nanostructured materials by the careful choice of suitable elements and nanoengineering steps. This new book summarizes the recent developments in nanocasting, including the principles of nanocasting, syntheses of novel nanostructured materials, characterization methods, detailed synthetic recipes and further possible development in this area. The book focuses on the synthesis of porous solids from the viewpoint of methodology and introduces the science of nanocasting from fundamental principles to their use in synthesis of various materials. It starts by outlining the principles of nanocasting, requirements to the templates and precursors and the tools needed to probe matter at the nanoscale level. It describes how to synthesize nano structured porous solids with defined characteristics and finally discusses the functionalization and application of porous solids. Special attention is given to new developments in this field and future perspectives. A useful appendix covering the detailed synthetic recipes of various templates including porous silica, porous carbon and colloidal spheres is included which will be invaluable to researchers wanting to follow and reproduce nanocast materials. Topics covered in the book include: * inorganic chemistry * organic chemistry * solution chemistry * sol-gel and interface science * acid-base equilibria * electrochemistry * biochemistry * confined synthesis The book gives readers not only an overview of nanocasting technology, but also sufficient information and knowledge for those wanting to prepare various nanostructured materials without needing to search the available literature.
Book Synopsis Mesoporous Molecular Sieves 1998 by : L. Bonneviot
Download or read book Mesoporous Molecular Sieves 1998 written by L. Bonneviot and published by Elsevier. This book was released on 1998-07-08 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: The original properties of mesoporous molecular sieves are so unique that the design of most existing catalysts could be reconsidered. It might indeed be of interest to introduce MMS either as a support or as the active phase, merely on the basis of their high surface areas, narrow pore size distribution and flexibility in composition. The recent literature provides examples of MMS based catalysts of many types such as acid-base solids, supported metals and supported oxides, mixed oxides, anchored complexes and clusters, grafted organic functional groups and others. Examples of all these developments are documented in the present proceedings including some spectacular new proposals. The new metallic (Pt) mesophases are specially worth mentioning because they represent a new approach to producing non-supported highly dispersed metals. In these proceedings the reader will find feature articles and regular papers from many worldwide groups, covering all aspects of synthesis, physical characterization and catalytic reactivity of MMS and their chemically modified forms. It is actually remarkable that this recent development brought together an even broader spectrum of scientists from traditionally unrelated fields such as those of liquid crystals, surfactants, sol-gels, amorphous oxides and mixed oxides, solid state, adsorbents and heterogeneous catalysts. Obviously, this is a fast-growing research area which triggers the imagination and creativity at the cross-road between material design, molecular surface tailoring and catalytic applications.
Book Synopsis Mesoporous Crystals and Related Nano-Structured Materials by : Osamu Terasaki
Download or read book Mesoporous Crystals and Related Nano-Structured Materials written by Osamu Terasaki and published by Elsevier. This book was released on 2004-05-25 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mesoporous Crystals and Related Nano-Structures Materials contains the invited lectures to be presented at the symposium on Mesoporous Crystals and Related Nano-Structures Materials, Stockholm, Sweden, June 1-2, 2004. This book highlights the core research that has led to such a fruitful and exciting field. Passing on, first hand, the synthesis of this novel material makes this book an important reference material to researchers young and old. * This book highlights the core research that has led to the fruitful and exciting field of mesoporous materials* It provides an overview of the studies which have led to the discovery of mesoporous materials as well as first preparations of mesoporous materials by researchers across the world* This book not only serves as important reference material but also as a source of scientific inspiration to all researchers working in the field of mesoporous materials
Book Synopsis Synthesis and Adsorptivity of Modified and Unmodified MCM-41 Mesoporous Materials by : Wararak Thachan
Download or read book Synthesis and Adsorptivity of Modified and Unmodified MCM-41 Mesoporous Materials written by Wararak Thachan and published by . This book was released on 2005 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Combined and Hybrid Adsorbents by : José M. Loureiro
Download or read book Combined and Hybrid Adsorbents written by José M. Loureiro and published by Springer Science & Business Media. This book was released on 2006-10-03 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book follows up an Advanced Research Workshop dedicated to the subject of adsorption. It presents an up-to-date review of the latest achievements in the synthesis, characterization and applications of hybrid organic-inorganic materials and of carbon and combined adsorbents. The modeling of the adsorption process, including the simulation of carbon masks used for both civil and military protection purposes is also addressed. Includes applications in environmental, military and post-disaster situations.
Book Synopsis Production of Biofuels and Chemicals with Bifunctional Catalysts by : Zhen Fang
Download or read book Production of Biofuels and Chemicals with Bifunctional Catalysts written by Zhen Fang and published by Springer. This book was released on 2017-12-27 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides state-of-the-art reviews, current research, prospects and challenges of the production of biofuels and chemicals such as furanic biofuels, biodiesel, carboxylic acids, polyols and others from lignocellulosic biomass, furfurals, syngas and γ-valerolactone with bifunctional catalysts, including catalytic, and combined biological and chemical catalysis processes. The bifunctionality of catalytic materials is a concept of not only using multifunctional solid materials as activators, but also design of materials in such a way that the catalytic materials have synergistic characteristics that promote a cascade of transformations with performance beyond that of mixed mono-functional catalysts. This book is a reference designed for researchers, academicians and industrialists in the area of catalysis, energy, chemical engineering and biomass conversion. Readers will find the wealth of information contained in chapters both useful and essential, for assessing the production and application of various biofuels and chemicals by chemical catalysis and biological techniques.
Book Synopsis Microporous and Mesoporous Solid Catalysts by : Eric G. Derouane
Download or read book Microporous and Mesoporous Solid Catalysts written by Eric G. Derouane and published by John Wiley & Sons. This book was released on 2006-08-14 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series offers practical help for advanced undergraduate, graduate and postgraduate students, as well as experienced chemists in industry and academia working with catalysts in organic and organometallic synthesis. It features tested and validated procedures, authoritative reviews on classes of catalysts, and assessments of all types of catalysts. Micro- and Mesoporous Solid Catalysts describes the use of zeolites and mesoporous solids as catalysts for the production of fine and specialty chemicals. Specific tips and hints are provided and some typical procedures are described in detail In addition to discussing the pros and cons, several major organic transformations are examined including aromatic substitutions, heterocyclic ring formation, amines synthesis, oligomerisation, oxidation and hydroxylation, and other regioselective and stereoselective reactions Features tutorial introductory chapters, including tips and hints for achieving successful organic transformations Important reactions are featured together with recommendations to resolve potential problems.
