Synthesis of novel fluorinated phosphine and their Rhodium(I) complexes and application of hydrogenation reactions in Supercritical carbon dioxide

Catalysis by metal complexes in homogenous solution has undergo important developments in nontraditional raection media such as water, fluorus solvents, ionic liquids and supercritical carbon dioxide (scCO2). On the other hand, the design of stereoselective reactions remains an important challenge in modern organic chemistry and plays a critical role in both pharmaceutical and agrochemical industries. Synthesis of many speciality chemicals in this area involves use of organic solvents. The solvents used are coming under close scruntiny because of environmental regulatory restrictions due to their toxicity. There is a great push in industry today to replace these solvents with environmentally benign solvents, such as water based solvents. However, most of the catalytic materials used in organic synthesis are not soluble in aqueous media. Furthermore, even if water-soluble catalyst is synthesized, the organic reactants and products may not be soluble in water and may be decompose, because of their sensitivity to water.A unique advantageus characteristic of scCO2 are that their density, polarity, viscosity, duffusivity and overall solvent strenght can be dramatically varied by relatively small changes in pressure and/or temperature. On the other hand the use of scCO2 as a reaction media offers the opportunity to optimize and potantionally control effect that solvent properties can have on selectivities. In addition, scCO2 is inert to most reaction, cheap, readily available and non-flammable.In this project we synthesized fluorinated derivatives of phosphine ligands and their rhodium complexes which are soluble and active catalyst for homogeneous reactions in scCO2. Solubility of synthsized compounds in scCO2 was measured at a pressure of 3000 psi in the temperature range of 333 ? 353 K in windowed reactor. Hydrogenation reactions were performed in scCO2 by charging a cylindrical stainless steel reactor (80 mL and 100 mL capacity) with catalyst and substrate (substrate/catalyst = 250 ? 650) followed by pressurization with hydrogen gas (10 bar) and CO2 (1750-2300 psi) in the reaction period range of 1-2-3 hours.