Design and Synthesis of Low Cost, Sustainable CO2-philes

Research conducted in the 1990s has demonstrated that one can design compounds which are “CO 2 -philic”, that is, they exhibit miscibility with CO 2 at pressures significantly below that of conventional alkyl-functional analogues. The use of such CO 2 -philic functional groups in the design of surfactants and chelating agents has allowed successful implementation of CO 2 in processes such as emulsion polymerization, heavy metal extraction, and others. However, the high cost of widely used fluorinated CO 2 -philes can render the economics of a CO 2 process unfavorable. Consequently, we have investigated the design of CO 2 -philes composed of only carbon, hydrogen, and oxygen. Using fundamental data on the thermophysical behavior of CO 2 as a guide, we focused on the design and synthesis of functionalized polyethers and copolymers of cyclic ethers and carbon dioxide that were found to be soluble in liquid and supercritical carbon dioxide. By choosing the proper amount of incorporated carbon dioxide, we can generate propylene oxide−CO 2 copolymers that exhibit lower miscibility pressures than fluoroethers with the same number of repeat units.