Chemical Synthesis Using Supercritical Fluids by Philip …
24/09/1999 · Chemical Synthesis Using Supercritical Fluids has 1 rating and 1 review
Chemical Synthesis Using Supercritical Fluids
There are also important advantages in the preparation of drug delivery systems using supercritical fluids rather than standard organic solvents.AB - In the study of chemical reactions for research and chemical plant engineering, external pressure and activity control has not been available in the past.
In addition, organic synthetic reactions using supercritical (CO2) fluids can eliminate the organic waste solvents that are used in traditional methods.
Chemical synthesis using supercritical fluids (Book, …
Coprecipitation of active pharmaceutical ingredients (API) with additives can provide the ability to add functionality to API’s at early stages of drug discovery and synthesis. It is with this objective that a number of drugs were recrystallized in the presence of structurally related additives. The rapid expansion of supercritical solution (RESS) process was evaluated to recrystallize the drug–additive mixtures. Results of RESS aided coprecipitation studies involving twelve drug–additive mixtures are reported in this manuscript. Characterization of these mixtures revealed a number of interesting phenomena. These include habit modification, solubility enhancement, particle size reduction, eutectic formation, reduction in crystallinity, amorphous conversion, hydrate formation, polymorph conversion and selective extraction. In viewing each of these phenomena from an application standpoint, this manuscript serves as proof of concept for altering the physicochemical and mechanical properties of API’s using supercritical fluid (SCF) coprecipitation. It was concluded from these studies that the rapid crystallization conditions offered by the SCF media alone does not provide the ability to consistently dope crystals. Competing mechanisms based on the relative solubility of drugs and additives in SCF media, as well as the selectivity of SCF solvents are to be taken into consideration while undertaking coprecipitations.
Book Description: The prospective green uses of utilizing liquid and supercritical carbon dioxide is discussed. The focus of the book is the chemical synthesis, polymers, and applications using carbon dioxide. The book contained some interesting chapters how supercritical carbon dioxide can make processes more “green” in conventional processes such as dry cleaning and enhancing properties of cement.
Chemical synthesis using supercritical fluids.
Synthesis of many specialty chemicals involve use of organic solvents. Our objective in this project is to determine the feasibility of carrying out organic synthesis reactions in supercritical fluids. We propose to use supercritical fluids (SCFs), specifically supercritical carbon dioxide (SCCO), as the reaction media. Although SCFs have seldom been explored for this purpose, they have properties that could make them nearly the ideal media for conducting organic synthesis reactions. SCFs are inert to most reactions, non-toxic, cheap, readily available, and environmentally acceptable. In addition, SCF densities can be varied over a wide margin by slight changes in temperature and/or pressure hence affecting reaction rate and selectivities by solubility and/or partial molar volume control.
W., "Continuous Synthesis of Surface-Modified Metal Oxide Nanoparticles Using Supercritical Methanol for Highly Stabilized Nanofluids," Chemistry of Materials, 20(20), 6301-6303(2008).
Synthesis Using SCF; Supercritical Fluids ..
Supercritical fluids - Supercritical fluids
Get this from a library! Chemical synthesis using supercritical fluids. [Walter Leitner; Philip G Jessop;]
Carbon dioxide (CO 2) is the most widely used supercritical fluid
Read "Nanoparticles synthesis using supercritical fluid technology – towards biomedical applications, ..
Supercritical fluids - Applications
Clean Chemical Synthesis in Water - Organic chemistry
Clean Chemical Synthesis in Water
Book Description: This book is a compilation of the the chemical reactions, structures and fundamental properties of supercritical fluid systems for the production of new compounds, nanomaterials, fibers, and films. Advances of supercritical material in increased selectivity and reduced waste is discussed. Other important topics of note include: fluid dynamics, catalysis, hydrothermal synthesis, surfactants, conducting polymers, and crystal growth.
10.1021/ie020326b - American Chemical Society
Within the last five years, there has been an explosion of research in supercritical fluids; more recent reports are now exploiting this medium for nanomaterials synthesis. An important goal for undergraduate curricula should be the constant upgrading of content to include the most leading-edge techniques. To this end, this Journal has published a few articles related to SCF technology for undergraduates. This article describes a module to introduce undergraduate inorganic chemistry students to an exciting area of nanotechnology that also incorporates SCFs, an environmentally-friendly alternative to organic solvents.
Defining chemical reactions of the polyphenol class
Octyl palmitate was enzymatically synthesized from palmitic acid and octanol. The synthesis of octyl palmitate was investigated in three supercritical fluids, namely, carbon dioxide, methane, and ethane, using three different enzymes. The effects of temperature, initial water content, alcohol concentration, and enzyme loading on the conversion were determined. Among the enzymes, Novozym 435 (immobilized) catalyzed the reaction, resulting in the highest conversion compared to the other lipases, irrespective of the solvent used. Further, Novozym 435 was active over a wider range of temperatures (35−65 °C) compared to the other two enzymes. The lowest esterification (76%) was obtained in supercritical carbon dioxide, while the highest esterification was obtained in supercritical methane (85%). The results thus indicate that for this reaction, among the systems investigated, supercritical methane and Novozym 435 are the best supercritical fluid and enzyme, respectively.
Applied Hydroformylation - Chemical Reviews (ACS …
Here we review major breakthroughs in the rapidly developing research area of nanomaterial synthesis in supercritical fluids focusing on both the fundamental science and processing advantages in the application areas of separations, assembly and scale-up of synthesis. Density-tunable control of the solvation strength, along with favorable interfacial tensions, wetting, and transport properties make supercritical fluids (SCFs) unique and potentially superior solvent media for the synthesis and processing of nanoscale metals and semiconductors. The steric repulsion between particle cores may be tuned by adjusting the solvent density to control the nanocrystal size and polydispersity during single-phase synthesis, and to achieve size-selective nanocrystal precipitation. Compressed solvents at the vapor pressure can also be used to deposit nanocrystal monolayers at controlled evaporation rates without dewetting at higher rates than conventional solvents. The high synthetic temperatures accessible in SCFs can be used to promote the crystallization of covalent nanomaterials, while maintaining a reaction environment capable of solvating reactants and capping ligands. This allows semiconductor nanocrystals exhibiting size-dependent photoluminescence to be synthesized at temperatures well above the boiling point of conventional solvents. Finally, gold nanocrystal seed particles can be used to synthesize bulk quantities of defect-free silicon and germanium nanowires, several micrometers in length.
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