Supercritical Fluids as Solvents and Reaction Media

Author: Gerd H. Brunner
Publisher: Elsevier
ISBN: 9780080542102
Format: PDF, Mobi
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Supercritical fluids behave either like a gas or a liquid, depending on the values of thermodynamic properties. This tuning of properties, and other advantageous properties of supercritical fluids led to innovative technologies. More than 100 plants of production size are now in operation worldwide in the areas of process and production technology, environmental applications, and particle engineering. New processes are under research and development in various fields. This book provides an overview of the research activities in the field of Supercritical Fluids in Germany. It is based on the research program "Supercritical fluids as solvents and reaction media" on the initiative of the "GVC-Fachausschuß Hochdruckverfahrenstechnik" (i.e. the German working party on High Pressure Chemical Engineering of the Society of Chemical Engineers). This research program provided an immensely valuable platform for exchange of knowledge and experience. More than 50 young researchers were involved contributing with their expertise, their new ideas, and the motivation of youth. The results of this innovative research are described in this book. - This book provides an overview of the research activities in the field of Supercritical Fluids in Germany - Contains results of projects within the research program on "Supercritical fluids as solvents and reaction media" on the initiative of the German working party on High Pressure Chemical Engineering of the Society of Chemical Engineers. - More than 50 young researchers were involved in contributing with their expertise, their new ideas, and the motivation of youth.

Supercritical Fluids

Author: E. Kiran
Publisher: Springer Science & Business Media
ISBN: 9401582955
Format: PDF, Mobi
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Supercritical fluids which are neither gas nor liquid, but can be compressed gradually from low to high density, are gaining increasing importance as tunable solvents and reaction media in the chemical process industry. By adjusting the pressure, or more strictly the density, the properties of these fluids are customized and manipulated for the particular process at hand, be it a physical transformation, such as separation or solvation, or a chemical transformation, such as a reaction or reactive extraction. Supercritical fluids, however, differ from both gases and liquids in many respects. In order to properly understand and describe their properties, it is necessary to know the implications of their nearness to criticality, to be aware of the complex types of phase separation (including solid phases) that occur when the components of the fluid mixture are very different from each other, and to develop theories that can cope with the large differences in molecular size and shape of the supercritical solvent and the solutes that are present.

Chemistry In Alternative Reaction Media

Author: Dave J. Adams
Publisher: John Wiley & Sons
ISBN: 9780470869659
Format: PDF, ePub, Docs
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At a time when environmental concerns are increasing, it'simportant that chemical processes are as environmentally friendlyas possible. This book outlines various methods for producinginorganic and organic solvents without the use of traditionalsolvents that can have detrimental effects on the environment. This is the first book to give extensive and exclusive coverageto the topic Includes important environmental issues This book will appeal to anyone with an interest in organicsynthesis; reaction chemistry; catalysis; and process development,and to undergraduate and graduate students of organic chemistry;catalysis; green chemistry; clean technology and environmentalchemistry courses.

Chemical Synthesis Using Supercritical Fluids

Author: Philip G. Jessop
Publisher: John Wiley & Sons
ISBN: 3527613692
Format: PDF, Mobi
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For 'better solutions' - this practical guide describes how to take advantage of supercritical fluids in chemical synthesis. Well-established in extractions and materials processing, supercritical fluids are becoming increasingly popular as media for modern chemical syntheses. Historically, the application of compressed gases has been restricted mainly to the production of bulk chemicals. In the last decade, however, research has turned to exploiting the unique properties of supercritical fluids for the synthesis of fine chemicals and specialized materials. Now that the necessary equipment is more readily available, the use of supercritical fluids should become more widespread in both laboratory and industrial scale syntheses. More than merely a concise introduction to the properties of supercritical fluids, here leading experts give a thorough, up-to-date account of chemistry in these alternative media. In-depth scientific commentary, detailed reaction protocols, descriptions of necessary equipment, and an outline of spectroscopic techniques add to the value of this handbook aimed at innovative synthetic chemists.

Enzymatic Reactions in Organic Media

Author: Ari Koskinen
Publisher: Springer Science & Business Media
ISBN: 9780751402599
Format: PDF, Docs
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The outlook of organic synthesis has changed many times during its tractable history. The initial focus on the synthesis of substances typical of living matter, exemplified by the first examples of organic chemistry through the synthesis of urea from inorganic substances by Liebig, was accepted as the birth of organic chemistry, and thus also of organic synthesis. Although the early developments in organic synthesis closely followed the pursuit of molecules typical in nature, towards the end of the 19th century, societal pressures placed higher demands on chemical methods appropriate for the emerging age of industrialization. This led to vast amounts of information being generated through the discovery of synthetic reactions, spectroscopic techniques and reaction mechanisms. The basic organic functional group transformations were discovered and improved during the early part of this century. Reaction mechanisms were elucidated at a growing pace, and extremely powerful spectroscopic tools, such as infrared, nuclear magnetic resonance and mass spectrometry were introduced as everyday tools for a practising organic chemist. By the 1950s, many practitioners were ready to agree that almost every molecule could be syn thesized. Some difficult stereochemical problems were exceptions; for example Woodward concluded that erythromycin was a "hopelessly complex target". This frustration led to a hectic phase of development of new and increasingly more ingenious protecting group strategies and functional group transformations, and also saw the emergence of asymmetric synthesis.

Extraction of Natural Products Using Near Critical Solvents

Author: M.B. King
Publisher: Springer Science & Business Media
ISBN: 9401121389
Format: PDF, Docs
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The aim of this book is to present the current state of the art of extracting natural products with near-critical solvents and to view the possibilities of further extensions of the technique. Relevant background theory is given but does not dominate the book. Carbon dioxide is the near-critical solvent used in most recent applications and inevitably receives prominence. In addition to general descriptions and reviews, the book contains three chapters by indus trial practitioners who describe in detail the operation of their processes and discuss the market for their products. Sections on the design of the pressure vessels and pumps required in these processes and on the acquisition of the data required for design are included. The costing of the processes is also discussed. There is good scope for combining a near-critical extraction step with other process steps in which the properties of near-critical solvents are utilised, for example as a reaction or crystallisation medium and a chapter is devoted to these important aspects. It is hoped that the work will be found to contain a great deal of specific information of use to those already familiar with this field. However the style of presentation and content is such that it will also be useful as an introduction. In particular it will be helpful to those wondering if this form of separation method has anything to offer for them, whether they are engineers, chemists or managers in industry, or in academic or research institutions.

Supercritical Fluids

Author: E. Kiran
Publisher: Springer Science & Business Media
ISBN: 9401139296
Format: PDF, Mobi
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Supercritical fluids are neither gas nor liquid, but can be compressed gradually from low to high density and they are therefore interesting and important as tunable solvents and reaction media in the chemical process industry. By adjusting the density the properties of these fluids can be customised and manipulated for a given process - physical or chemical transformation. Separation and processing using supercritical solvents such as CO2 are currently on-line commercially in the food, essential oils and polymer industries. Many agencies and industries are considering the use of supercritical water for waste remediation. Supercritical fluid chromatography represents another, major analytical application. Significant advances have recently been made in materials processing, ranging from particle formation to the creation of porous materials. The chapters in this book provide tutorial accounts of topical areas centred around: (1) phase equilibria, thermodynamics and equations of state; (2) critical behaviour, crossover effects; (3) transport and interfacial properties; (4) molecular modelling, computer simulation; (5) reactions, spectroscopy; (6) phase separation kinetics; (7) extractions; (8) applications to polymers, pharmaceuticals, natural materials and chromatography; (9) process scale-up.

Supercritical Fluids Technology in Lipase Catalyzed Processes

Author: Sulaiman Al-Zuhair
Publisher: CRC Press
ISBN: 1351231421
Format: PDF, Kindle
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Enzymes are currently used in various industries, most commonly in food, detergents, and pharmaceuticals production. Lipases are hydrolytic enzymes that demonstrate great potential as an alternative to conventional catalysts in a number of industrial applications. A complete understanding of enzymes, and their proteins structure and environmental behavior, can greatly aid in the further development of industrial applications. Supercritical Fluids Technology in Lipase Catalized Processes provides basic information about enzymes, their sources, reaction kinetics, and main industrial applications. The book focuses in lipases. their main sources, structure, and features, with an emphasis on their specificity and interfacial activity, and presents proven techniques for isolating, extracting, and purifying. Comprised of six compact chapters, this comprehensive guide introduces: Immobilization techniques and immobilized lipases that allow repeated use (which is essential from an economic point of view) Different bioreactor configurations using immobilized lipases The latest information on the available technologies in lipolytic reactions The advantages of nonaqueous media in biochemical synthesis over aqueous and solvent-free systems Material on the use of lipases in nonaqueous media to overcome the drawbacks usually encountered with the use of conventional chemical catalysts The use of supercritical fluids (SCFs) as a green alternative reaction medium Factors affecting the physical properties of lipases in this medium and, hence, their activity and stability A case study using supercritical carbon dioxide (SC-CO2) for biodiesel production Novel, cutting-edge technology, using immobilized enzymes to reduce the overall production cost Supercritical Fluids Technology in Lipase Catalized Processes outlines the main industrial applications of common enzymes and discusses relevant challenges and innovations emerging in the field.

Supercritical Fluid Extraction

Author: Mark McHugh
Publisher: Elsevier
ISBN: 0080518176
Format: PDF, ePub
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Supercritical Fluid Extraction is a technique in which CO2 is used under extremely high pressure to separate solution (e.g., removing caffeine from coffee). Separations is basic to all process industries and supercritical fluid extraction is a specific type which is receiving a high level of attention. The book will combine basic fundamentals with industrial applications. The second edition has been expanded and updated and includes new chapters on chromatography and food processing. "...this is an excellent book which is both instructive and amusing to read. Its true value is neatly summarised in one of the closing sentences: 'We have supplied you with the guidelines and criteria which you can now apply when considering supercritical fluids for your own needs.'' - Chemistry in Britain, February 1995

Green Solvents I

Author: Ali Mohammad
Publisher: Springer Science & Business Media
ISBN: 9400717121
Format: PDF, ePub, Mobi
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The conventional solvents used in chemical, pharmaceutical, biomedical and separation processes represent a great challenge to green chemistry because of their toxicity and flammability. Since the beginning of “the 12 Principles of Green Chemistry” in 1998, a general effort has been made to replace conventional solvents with environmentally benign substitutes. Water has been the most popular choice so far, followed by ionic liquids, surfactant, supercritical fluids, fluorous solvents, liquid polymers, bio-solvents and switchable solvent systems. Green Solvents Volume I and II provides a throughout overview of the different types of solvents and discusses their extensive applications in fields such as extraction, organic synthesis, biocatalytic processes, production of fine chemicals, removal of hydrogen sulphide, biochemical transformations, composite material, energy storage devices and polymers. These volumes are written by leading international experts and cover all possible aspects of green solvents’ properties and applications available in today’s literature. Green Solvents Volume I and II is an invaluable guide to scientists, R&D industrial specialists, researchers, upper-level undergraduates and graduate students, Ph.D. scholars, college and university professors working in the field of chemistry and biochemistry.