Homogeneous Catalysis in Supercritical Carbon Dioxide | Research Project Database | Grantee Research Project | ORD | US EPA
Homogeneous Catalysis in Supercritical Carbon Dioxide
Title: Homogeneous Catalysis in Supercritical Carbon Dioxide
This project focuses on pollution prevention in chemical process industries by replacing organic solvents used in homogeneous catalysis with environmentally friendly solvents. We propose to evaluate supercritical fluids as the solvent in homogeneous catalysis. Furthermore, supercritical fluids bring desirable advantages when used as the reaction media.
Homogeneous catalysts are normally soluble metal salts or complexes that are dissolved in a suitable organic solvent which is used as the reaction medium. These solvents are coming under close scrutiny because of their toxicity, and there is a motion in industry today to replace these solvents with environmentally benign solvents. Supercritical fluids have properties that could make them nearly the ideal media for conducting homogeneous catalytic processes that involve reactions of gas phase reactants with soluble liquid or solid substrates. Gases are completely miscible with supercritical fluids. Therefore, gas phase reactant concentrations in the supercritical media would typically be much higher than achievable in normal liquids. Furthermore, very large negative partial molar volumes in supercritical systems can be exploited to adjust rate constants of many reactions in order to achieve high selectivities.
In this project we propose to use supercritical carbon dioxide as the reaction medium for homogeneous catalysis. Supercritical carbon dioxide is non-toxic and environmentally acceptable. It is non- flammable, thus its use does not introduce a safety hazard during operation. It has a low critical temperature, 31.3 ?C and a moderate critical pressure, 73.8 bar (1073 psia); it is cheap and readily available in large quantities.
We propose to concentrate on two classes of reactions commonly performed by homogeneous catalysis employing organic solvents, namely hydroformulation and oligomerization. Hydroformulation is a carbon insertion reaction, very important in building new products, whereas oligomerization reactions are widely used on an industrial scale either to provide high added value chemicals or to upgrade by-product olefinic streams. Both reactions are used extensively in manufacture of high value fine chemicals and/or pharmaceuticals.
RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Waste, Sustainable Industry/Business, cleaner production/pollution prevention, Environmental Chemistry, Physics, Hazardous Waste, Hazardous, oligomerization, cleaner production, environmentally conscious manufacturing, catalysts, hydroformulation, carbon dioxide, organic solvents , chemical processing, solvent replacements, homogeneous catalysis, solvent substitution, pollution prevention, supercritical fluid reaction media, environmentally-friendly chemical synthesis, green chemistry, pharmaceutical industry, soluble metal salts