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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"Acid Catalysis"”.
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Lewis acid catalysis in organic synthesis
"Gadolinium triflate (Gd(OTf)₃) was found to be a simple and efficient catalyst for the acetylation of alcohols and amines in both conventional organic solvents and as well as in room temperature ionic liquids (TRIL). Acetylation reactions using acetic anhydride as the reagent proceed in excellent …
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Carbon-Carbon Bonds Formed by Lewis Acid Catalysis or Photoactivation
… propargylic alcohols, organoboronates, and Lewis acids. Lewis acids can also be used to facilitate a mild Friedel-Crafts reaction between electron-rich aromatics and allylic or benzylic alcohols. Moreover, these methods can be applied to the synthesis of natural products. Finally, photoactivation …
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Electrostatically Enhanced Phosphoric Acids and Their Applications in Brønsted Acid Catalysis
Different 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 …
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Probing the Impact of Solvent on Lewis Acid Catalysis via Fluorescent Lewis Adducts
… developed to measure the strength of a Lewis acid. However, a major challenge for these measurements lies in the complexity that arises from variables, such as solvent and other fundamental interactions, as well as perturbations of Lewis acids as their reaction environment changes. Herein, we …
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Borox catalysis : a new frontier in chiral Bronsted acid catalysis derived from chiral borate anions
… on the development of the new chiral Brønsted acid catalysts, large-scale synthesis, novel reaction methodologies and understanding their mechanisms by experimental/computational analysis. In due course of time, a pool of unprecedented chiral Brønsted acid catalysts known to be "BOROX" …
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Stress relief: Exercising Lewis acid catalysis for donor-acceptor cyclopropane ring-opening annulations, a basis for new reaction methodologies
… relevant scaffolds. Unique, efficient, Lewis acid-catalyzed intramolecular cyclization strategies for the construction of functionalized polycycles using Friedel-Crafts-type alkylation sequences are presented to expand the reaction repertoire of the molecular architect. Generally, products …
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Asymmetric synthesis of amines by the catalytic enantioselective additions of hydrazoic acid to ketenes
… to a ketene is likely occurring by the Bronsted acid catalysis mechanism. The evidence in support of the Bronsted acid catalysis mechanism include stereochemical and spectroscopic results, which are consistent with data from other additions believed to occur by the Bransted acid catalysis …
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Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions
… of new methodology in the field of Brønsted acid catalysis enabling rapid synthesis of medicinally relevant compounds. It is foreseen that small molecule sulfonic acids evaluated in this research project will unveil new asymmetric carbon carbon bond forming reactions between substrates …
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Supramolecular templating of mesoporous zirconia-based nanocomposite catalysts
Acid catalysis forms the basis of major hydrocarbon reactions in the petroleum industry, including paraffin isomerization, catalytic cracking, and alkylation. The environmental problem associated with the refining of hydrocarbons stems from the corrosive catalysts relied upon by many acid catalytic …
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Inter- and intramolecular (4+2) cycloaddition reactions and tandem inter- and intramolecular (4+2)/intramolecular (3+2)cycloaddition reactions of nitroalkenes
… cycloadditions of nitroalkenes with Lewis acid catalysis were investigated. The intramolecular cycloadditions of nitroalkenes were found to be completely stereoselective for trisubstituted nitroalkenes. Intermolecular cycloadditions of aromatic nitroalkenes were found to proceed with …
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Borinic Acid-catalyzed Ring-opening of Epoxy Alcohols
Borinic acid catalysis has been used by our group to effect ring-opening and rearrangement reactions of 2,3-epoxy alcohols via reversible borinate ester formation. This work focuses on expanding the mode of borinic acid catalysis to the activation of 3,4-epoxy alcohols for regioselective …
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Applications of 2,3-Diketoesters in Organic Synthesis and Stereoselective Transformations
… yield to form dihydrofuranols that undergo acid catalyzed dehydration under mild conditions to generate 3-methoxyfuran-2-carboxylates in good yield. Oxidation of ζ-keto-α-diazo-β-ketoesters that are formed by zinc triflate catalyzed Mukaiyama-Michael condensation of methyl diazoacetoacetate …
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Deoxyribozyme-Mediated Synthesis of Branched Nucleic Acids and Application to Modulation of Ribozyme Catalysis
… for understanding fundamental aspects of nucleic acid catalysis and for providing practical reagents.
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Marcus Theory Applied To Acetal Cleavage And Aldol Reactions
The acid catalyzed and uncatalyzed hydrolysis of the acetal 2,2-dimethoxypropane (DMOP) and the ortho ester trimethylorthoacetate (TMOA) have been studied in aqueous solution at 25{dollar}spcirc{dollar}C. Theoretical and experimental evidence have been found for a base catalyzed E2 mechanism of …
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Brønsted acid-catalyzed reaction of alkynyltrifluoroborates with acetals and ketals
… in synthetic organic chemistry. Brønsted acid catalysis is a powerful synthetic tool to make many different compounds, however, the current carbon-based nucleophiles are the major limitation of acid-catalyzed reactions. In effort to expand repertoire of Brønsted acid compatible …
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SYNTHESIS AND CHARACTERIZATION OF BIODIESEL FUELS FROM FURFURYL ALCOHOL AND SPENT COFFEE GROUNDS
… alcohols, and catalysts. In this study, fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) were produced from their respective alcohols and coffee oil, using either a basic (K<sub>2</sub>CO<sub>3</sub>) catalyst or an acidic catalyst (H<sub>2</sub>SO<sub>4</sub>). Fatty acid …
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Mechanistic Modeling of Biodiesel Production via Heterogeneous Catalysis
… been prepared through homogeneous basic catalysis, heterogeneous acid catalysis has been investigated recently due to its ability to convert cheaper but high free fatty acid content oils such as waste vegetable oil while decreasing production cost. In this work, the esterification of free …
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Efforts towards the Total Synthesis of Azaspiracid-3
Azaspiracid, a structurally complex marine toxin isolated from the mussel Mytilus edulis in Killary Harbor, Ireland, represents a new class of marine metabolites unrelated to any previous known agent of diarrhetic shellfish posioning. As such, the natural product has spurred considerable interest …
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