Tailoring the Ionic Liquid Environment in Nanopores for Green Reaction Engineering

This project aims to more thoroughly understand how to manipulate the solvation environment of ionic liquids (ILs) confined within nanopores so that recent advances in homogeneous IL-based catalysts can be translated to heterogeneous thin film, membrane and particle systems for the engineering of chemical reactions and separations. ILs are compounds made up of pairs of oppositely charged ions that are present in the liquid state at or near room temperature. They have been adopted widely as solvents in catalysis because of their ability to dissolve a variety of materials (including otherwise difficult to dissolve biopolymers such as cellulose and lignin), their low volatility, and their favorable polar environment. Despite these advantages, ILs are still relatively expensive so their use as bulk solvents with homogeneous catalysts is not desirable for all applications. Here, we investigate the loading of ILs into the oriented, well defined pores of surfactant-templated thin metal oxide films. Silicon dioxide is used as the base material because of its versatility in synthesis and functionalization. The goals are (1) to measure the local structure and solvation environment of ILs loaded into the pores as a function of pore size, type of IL and functionalization of the pore with IL-like ligands, (2) to use fluorescent and spectroscopic probes to learn to tune the local environment of traditional (e.g. chromium) and greener (e.g. aluminum) transition metals and their ligands, to give catalytic activities comparable to or better than in homogeneous catalysts, and (3) to use what is learned about IL immobilization to move toward systems able to provide stable, effective catalysis for catalysis of solutes dissolved in water.