Membrane Recovery of Homogeneous Catalysts (TSE 99-D)

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Abstract Proposal number: CTS-9985552 Proposal type: Response to NSF 99-108, NSF/EPA Technology for a Sustainable Environment Program Principal investigators: Mary Rezac and Haskell Beckham Affiliation: Georgia Institute of Technology Membrane Recovery of Homogeneous Catalysts Homogeneous catalysts are employed for chemical production because of their high reaction rates and selectivity. However, recovery and recycle of these catalysts is difficult and produces significant waste (approximately 4 million tons in 1996). Conventional techniques are not well suited to this separation. This research program examines the ability of chemically stable membranes developed from crosslinked diacetylene-functionalized polymers to selectively recover homogeneous catalysts from either aqueous or non-aqueous reaction mixtures. If successful, this technology could greatly expand the use of highly selective but often expensive homogeneous catalysts and dramatically reduce the volume of undesired by-products formed via conventional heterogeneous catalysis systems. The hypothesis of this study is that the separation of an organic product from a metal-ligand catalyst can be achieved with an organic polymer membrane that provides selectivity based on differences in the diffusion rates of the two compounds. Tailoring of mobility-based selectivity can be realized through control of the molecular motion of the polymer chains. Selective crosslinking of the polymer matrix can be used to gain this control. Polymers topochemically crosslinked via a diacetylene functionality will be investigated to probe the ability of this unit to prevent polymer swelling and the concurrent loss of selectivity without markedly reducing transport rates of desired penetrants. The crosslink density of the samples will be systematically varied to evaluate the posed hypothesis. Measurement of the solubility and diffusion coefficient for each penetrant will be made. The performance of the membrane in the recovery of homogeneous catalyst and the subsequent activity of the recovered catalyst are being evaluated.