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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Potassium fluoride as a base in organic reactions solubilized by 18-crown-6

Henson, Thomas Ray 05 1900 (has links)
No description available.
2

The use of new reactions for novel polymerizations, polymers and architectures

Coady, Daniel Joseph 23 May 2013 (has links)
The design, synthesis and characterization of novel conjugated polymers are described. Using a coupling reaction recently developed within our labs, polymers were constructed through triazene linkages generated by joining N-heterocyclic carbenes (NHCs) with organic azides. This triazene reaction produced polymer of sufficiently high molecular weight as to be spin-coated and rendered conductive upon doping with iodine. The reaction also has potential for executing post-polymerization modifications. This was evidenced through rapid functionalization of poly(4-methylazido-styrene) via triazene formation using a commercially available N-heterocyclic carbene (NHC). A formal anion metathesis of benzobis(imidazolium)s was used to transform neutral block copolymers into block ionomers. Further investigation of the block ionomers revealed their solvent mediated self assembly. The gradual change of organic to aqueous media caused the adoption of a three-dimensional micelle conformation as determined by transmission electron microscopy and dynamic light scattering. Through the exploitation of carbene-carbon disulfide adducts, new chain transfer agents were generated. After 2-dithiocarboxylate-imidazolium adduct formation, alkylation was performed with benzyl bromide. The resulting charged chain transfer agent was tested for its ability to moderate radical addition fragmentation (RAFT) polymerizations of styrene. A considerable increase in transfer kinetics as compared to that of commonly used RAFT agents was observed whilst retaining low polydispersity and molecular weight control. The rate enhancement is presumably due to the electron withdrawing imidazolium activating the thionyl towards the nucleophilic radical while retaining effective fragmentation. Ion coordinating macrocycles were affixed to a poly(methacrylate) scaffold for employment as electrolyte extractants. Polymer bound calix[4]pyrrole was found to complex fluoride and chloride with sufficient strength as to extract tetrabutylammonium salts from water. Enhanced extraction abilities were observed when calix[4]pyrrole was used in conjunction with benzo-15-crown-5. Methacrylate polymers containing both macrocycles affected the removal of aqueous potassium fluoride from a biphasic water/dichloromethane mixture. To provide evidence for the presence of potassium fluoride within the dichloromethane layer, ¹⁹F NMR and flame emission spectroscopy were used. / text

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