This award is to support a cooperative research by Dr. Stephen Ritchie, Department of Chemical Engineering, University of Alabama, Tuscaloosa, Alabama and Dr. Elham El Zanati, National Research Center (NRC), Cairo, Egypt. They plan to conduct research on Functionalized Membranes for Acid Catalysis. The research is to address the development and fundamental understanding of a new class of solid-phase acid catalysts based on functionalized membranes. Acid groups are added to a microfiltration membrane by sulfonation of polystyrene grafts in the pores of the membrane. Polymer grafts are immobilized in the membrane pores by in-situ polymerization of styrene. Simple application of a low pressure gradient across the membrane is sufficient to achieve excellent contact between acid sites and the reactants. The importance of convective flow (only possible in the membrane) is that it enables the complete and rapid accessibility of reactants to acid sites. Experimental efforts will be performed by junior scientists including undergraduate and graduate students, with an emphasis of creating opportunities for Involvement and dissemination of results.
Intellectual Merit: Acid catalysis is a critical enabling process in the chemical process industry. Conventional acid catalysis is performed in homogeneous solution (mineral acids) or by contact with a solid phase (e.g., ion exchange resins). The former offers excellent reactant accessibility to the catalyst, but suffers from problems with corrosion and catalyst recovery. The use of solid phase catalysts simplifies catalyst recovery with less corrosion, but introduces the new problem of hindered accessibility because transport is dominated by diffusion. This research should lead to a better understanding of the grafting process with polymerization by free radical processes and experimental determination of operating parameters during reaction. Reactions of interest include esterification and alkylation for ethyl acetate and isooctane, respectively. For the latter system, functionalized membranes are ideally suited to overcome problems seen with Nafion dispersed on silica, where accessibility and deactivation by the support result in degradation of catalyst activity.
Broader Impact: The proposed work will result in the development of a new acid catalyst for the chemical process industry. It has beneficial applications for alternative fuels, and biofuels in particular. Acid catalyzed esterification is important for the production of biodiesel when the feedstock contains free fatty acids. These fatty acids can be excluded from conventional solid phase acid catalysts, and are susceptible to side reactions in homogeneous solution. A catalytic membrane would be a way to overcome these problems, and may have a major effect on the large scale production of biodiesel and other alternative fuels. These materials may also offer an alternative to existing solid phase acid catalysts for alkylations, which suffer from low accessibility and deactivation. The work will involve two US undergraduate students. There will be exchange of visits by the US P.I. and the Egyptian collaborators to each others laboratories and this should expand relations between the scientific communities in both countries.
This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.
