Fluid Phase Behavior Of Systems Involving High Molecular Weight Compounds And Supercritical Fluids

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.

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 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

New directions in supercritical fluids science and technology, fluorescence spectroscopy studies of intermolecular interactions in supercritical fluids, solvation structure in supercritical fluid mixtures based on molecular distribution functions, gibbs-ensemble Monte Carlo simulations of phase equilibria in supercritical fluid mixtures, spectroscopic determination of solvent strength and structure in supercritical fluid mixtures, partition coefficients of polyethyle glycols in super critical carbon dioxide, experimental measurement of supercritical fluid-liquid phase equilibrium, vapor-liquid equilibria of fatty acid esters in supercritical fluids, four-phase equilibrium of two ternary organic systems with carbon dioxide, direct viscosity enhancement of carbon dioxide, inverse emulsion polymerization of acrylamide, interaction of polymers with near-critical carbon dioxide, fundamental kinetics of methanol oxidation in supercritical fluids, thermodynamic analysis of corrosion of iron alloys in supercritical water, electrochemical measurements of corrosion of iron alloys in supercritical water, phase and reaction equilibria considerations in the evaluation and operation of supercritical fluid reaction processes, kinetic model for supercritical delignification of wood, gas antisolvent recrystallization solids formation after the expansion of supercritical mixtures, food, pharmaceutical, and environmental applications, design of commercial plant.

The potential of supercritical fluid methods is presented in a comprehensive way. On the basis of a careful discussion of physical and chemical principles, the application of this method in process technology is demonstrated.

Foaming with Supercritical Fluids, Volume Nine provides a comprehensive description of the use of supercritical fluids as blowing agents in polymer foaming. To this aim, the fundamental issues on which the proper design and control of this process are rooted are discussed in detail, with specific attention devoted to the theoretical and experimental aspects of sorption thermodynamics of a blowing agent within a polymer, the effect of the absorbed blowing agent on the thermal, interfacial and rheological properties of the expanding matter, and the phase separation of the gaseous phase, and of the related bubble nucleation and growth phenomena. Several foaming technologies based on the use of supercritical blowing agents are then described, addressing the main issues in the light of the underlying chemical-physical phenomena. Offers strong fundamentals on polymer properties important on foaming Outlines the use of supercritical fluids for foaming Covers theoretical points-of-view, including foam formation of the polymer/gas solution to the setting of the final foam Discusses the several processing technologies and applications