Browsing by Subject "catalyst"
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Item Electrostatically Enhanced Phosphoric Acids and Their Applications in Brønsted Acid Catalysis(2018-06) Ma, JieDifferent types of Brønsted acid catalysts are commonly used in a wide variety of organic transformations and are of continuing interest because there is a general need to carry out reactions in a faster and higher yielding manner with greater selectivities. Phosphoric acid derivatives, with their fairly strong acidity and structural flexibility that enables them to be incorporated into rigid organic frameworks, are one of the most efficient and versatile classes of Brønsted acids. Herein, a novel type of electrostatically enhanced phosphoric acids that contain positively charged ion centers are synthesized and studied. The activities of achiral phosphoric acids with alkylated pyridinium ion moieties were examined in a variety of organic transformations. In addition, the activities and enantioselectivities of a series of chiral phosphonium ion tagged phosphoric acids were also evaluated in several different organic reactions. The study of electrostatically enhanced phosphoric acids was found to provide promising avenues for developing novel Brønsted acid catalysts.Item Polymerization Kinetics of Cyclic Esters by Metal Alkoxide Complexes and Catalytic Decarbonylation of Bio-Derived Carboxylic Acids to Commodity Alkenes(2014-05) Miranda, MariaPlastic materials are an integral part of modern life; however, nearly every plastic, or polymer, is derived from petroleum resources, which are non-sustainable, non-degradable, and can be toxic to humans and the environment. Developing methodologies to synthesize and characterize alternative materials that are degradable, safe, and sustainable has therefore been a vibrant research area. This thesis describes two approaches towards the development of sustainable polymers and monomers (the building blocks from which polymers are made). The first aims to understand the fundamental mechanistic details of metal-catalyzed ring-opening polymerization of renewable cyclic ester monomers to degradable polyesters. The second targets the catalytic synthesis of common petroleum-based monomers from sustainable and biomass-derived carboxylic acids.