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>Development of porous organic and inorganic materials for heterogeneous catalysis: Studies in the hydrolytic kinetic resolution of propylene oxide.
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Development of porous organic and inorganic materials for heterogeneous catalysis: Studies in the hydrolytic kinetic resolution of propylene oxide.
An advantage to using heterogeneous catalysts is the ease with which these catalysts can be separated from products and the potential for reuse. The research described in this dissertation focuses on the development of porous materials with immobilized chiral cobalt-salen complexes using template copolymerization methods. These materials function as heterogeneous catalysts in the hydrolytic kinetic resolution of propylene oxide, a chemical transformation reported to proceed through a bimolecular pathway. To function in this transformation, the resulting materials must allow site-site interaction to occur.; Materials allowing site-site interactions are prepared by two different methods. The first method, described in Chapter 2, varies the template:crosslinker ratio during copolymerization to create a series of materials from a common template that display varying degrees of catalytic activity in the hydrolytic kinetic resolution of propylene oxide. The observed trend shows that the activity of the material increases as the concentration of template used to prepare the material increases, but reusability of the material over three cycles appears to be variable.; Chapter 3 describes a modification made to the template that allows for the installation of a fifth ligand within the active site. The effect this endogenous ligand has on the activity and reusability of the material is discussed. The resulting materials prepared with increased concentrations of template exhibited the highest degree of activity and were reusable over three cycles.; Chapter 4 discusses the second method for creating sites within the material containing more than one metal ion. This approach involves the use of dimer templates with the metal ions linked together by a bridging ligand. The function of the resulting materials was tested in the hydrolytic kinetic resolution of propylene oxide and the results are reported and compared to the materials from Chapters 2 and 3.; Chapter 5 discusses progress towards the development of porous inorganic materials as heterogeneous oxidation catalysts. Isolation and characterization of the porphyrin template, preliminary sol-gel polymerization studies and initial metal ion insertion attempts are described.
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