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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 271 for “"ethers"”.
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Ethers of 2-Duroylresorcinol
Made available in DSpace on 2014-12-05T19:37:50Z (GMT). No. of bitstreams: 1 6200565.pdf: 3164334 bytes, checksum: cc05cf2ac251418b43c4e5138c138e7d (MD5) Previous issue date: 1961
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Fluorine-Containing Poly(aryl ethers)
… and electrical properties of poly(aryl ethers). While the presence of fluorine is known to improve these properties, it is also very expensive; therefore, determination of the best placement of fluorine in the polymer backbone is necessary in order to maximize the above benefits while …
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Trifluoroethyl enol ethers, dienol ethers, and acetals: an investigation of their preparations, reactivities, and synthetic applications
… were trifluoroethoxy substituted ketals, enol ethers, and dienol ethers. The ketal and enol ether work involved developing methodology for the large scale preparation of these structures as well as studies detailing their behavior. For the TFE ketals, preparation involved an acid-catalyzed …
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Reactions of quinones with aromatic ethers.
The reactions between quinones and aromatic compounds in the presence of acids are surveyed; and a summary of the methods used for preparing triphenylenes is outlined. Mono- and di-arylquinones have been prepared by the arylation of benzoquinones with diazotised 3,4-dimethoxyaniline (Meerwein …
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Large-scale production of oxymethylene dimethyl ethers
Oxymethylene dimethyl ethers (OME) show promising solubility and combustion properties for applications in various chemical processes and sectors. They enable clean and quasi soot-free combustion, which can strongly reduce NOx emissions. Besides reducing local emissions, OME can strongly reduce CO2 …
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Biomonitoring polybrominated diphenyl ethers in lactating women
… lipid-soluble polybrominated diphenyl ethers (PBDEs). The goal of this project was to determine the levels of PBDEs in breast milk of lactating women from the Seacoast region of New Hampshire and to examine potential relationships between PBDE levels in breast milk and stage of …
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Explorations with optically active, cage-annulated crown ethers.
A variety of optically active macrocyclic crown ethers that serve as "host" systems that are capable of differentiating between enantiomeric "guest" molecules during host-guest complexation have been prepared via incorporation of chiral elements into the crown ring skeleton. The ability of these …
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The cationic ring-opening polymerization of cyclic ethers
… and copolymerizntion of different cyclic ethers were studied using mainly a cationic system of iinitiation. BF30Et2/ethanediol. The cyclic ethers reacted differently showing that ring strain and basicity are the main driving forces in cationic ring opening polymerizaion. In most cases it …
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Synthesis of Aryl Ynol Ethers and Their Synthetic Applications
Ynol ethers are known as very important synthetic intermediates that are widely used in the syntheses of natural products and pharmaceuticals. The ynol ethers have also been used as ideal precursors of ketenes and surrogates of alkynes with a higher oxidation state in many reactions. However, few …
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The ring opening polymerization of ring strained cyclic ethers
The kinetics and mechanisms of the ring-opening polymerization of oxetane were studied using cationic and coordinated anionic catalysts. The cationic initiators used were BF30Et2!/ethanol, BF30Et2!/ethanediol and BF30Et2/propantriol. Kinetic determinations with the BF30Et2/diol system indicated …
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Drug release from pellets and matrices based on cellulose ethers.
T.his t~~sis examines the use of hydro~yprol?ylmethylcellulose (HPM~) of di.tJer~nt VIScosities and ethylcellulose aqueous dispersion (Surelease), alone or m combination with each other, to control the release of metoclopramide hydrochloride or diclofenac sodium from coated pellets or matrices. The …
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Computational Studies of Protonated Cyclic Ethers and Benzylic Organolithium Compounds
Protonated epoxides feature prominently in organic chemistry as reactive intermediates. Gas-phase calculations studying the structure and ring-opening energetics of protonated ethylene oxide, propylene oxide and 2-methyl-1,2-epoxypropane were performed at the B3LYP and MP2 levels (both with the …
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Controlled polymerization of alkyl vinyl ethers via 'covalent' propagating species
The study of the polymerization of alkyl vinyl ethers initiated by HI/I₂ catalyst is directed into two areas: the kinetics of the polymerization and the strategy of amine functionalized prepolymer synthesis. The polymerization reactions show living behavior in nonpolar solvents at low temperatures. …
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Synthesis and characterization of poly(arylene ethers) and functionalized oligomers
Molecular weight control and endgroup functionalization in poly(arylene ether sulfones) has been achieved by two synthetic routes. The first utilizes DMSO/sodium hydroxide and aminophenol to introduce the amine functionality. This route, though synthetically useful, suffers from serious …
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