Design and Applications of Microporous Crystals with Molecular Recognition Properties

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The purpose of this project is to synthesize new microporous crystals with high shape-selectivity and specific chemical affinity for adsorption, catalytic conversion and separation.1.Molecular recognition by chemically modified pillared claysAlumina pillared clay was modified by Na ion loading, which showed high selectivity to the separation of xylene isomers. Chemical modification of SiO2-TiO2 sol pillared clays was also studied.2.Synthesis of pillared clays with mixed oxides and their adsorption propertiesPillared clays with Al2O3-NiO mixed oxide were synthesized. The resulting pillared structure showed higher thermal stability than alumina pillared clays.3.Synthesis of silica pillared clays with high surface area and high thermal stabilitySilica sol particles are negatively charged and cannot be introduced between the silicate layrs of clay. The silica sol particles were positively charged by the deposition of iron oxide on the surface. Montmorillonite was pillared with the modified sol particles. On washing with acid, the iron oxide was easily removed, and silica pillared clays were obtained, which had high surface area and high thermal stability4.Synthesis of non-silicate pillared materials and their adsorption and catalytic propertiesA layr structured manganese titanate, RbxMnxTi2-xO4, was pillared with silica. The adsorption studies suggested that the pillared compounds had micropores like zeolites. The compounds showed a high catalytic activity against the oxidation of CO.5.Preparation and Gas permeability of highly oriented pillared clay membranePillared clays were deposited as thin membrane onto porous alumina substrate. The membranes were free from pin holes and cracks. Permeabilities of various kinds of gasses were measured up to 500ﾟC.Hydrogen and helium showed an activated diffusion through the interlayr pores.