Morphological control of multifunctionalized mesoporous silica nanomaterials for catalysis applications

dc.contributor.advisor Victor S.-Y. Lin Huh, Seong
dc.contributor.department Chemistry 2018-08-25T00:51:10.000 2020-06-30T07:56:38Z 2020-06-30T07:56:38Z Thu Jan 01 00:00:00 UTC 2004 2004-01-01
dc.description.abstract <p>I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu 2+ adsorption capacity tests. The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu2+ adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups.;An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems.;I also created a cooperative dual catalyst system that is capable of activating two different substrates in aldol reaction, Henry reaction and cyanosilylation. One catalytic group activates the nucleophile, another organic group simultaneously activates the electrophile to enhance the total reaction rate. I systematically varied the amount of two organic groups and performed the three model reactions to compare rate enhancements.</p>
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dc.identifier archive/
dc.identifier.articleid 2697
dc.identifier.contextkey 6105303
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/1698
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 21:08:48 UTC 2022
dc.subject.disciplines Inorganic Chemistry
dc.subject.disciplines Materials Science and Engineering
dc.subject.disciplines Organic Chemistry
dc.subject.keywords Chemistry
dc.subject.keywords Inorganic chemistry
dc.title Morphological control of multifunctionalized mesoporous silica nanomaterials for catalysis applications
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11 dissertation Doctor of Philosophy
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