Reactions of in Situ Generated Cyclic Ketene-N,N-,-N,O- and -N,S-Acetals: Acid Catalyzed Olefinations of Bio-Oil

This dissertation research is based on two reactions, including those of cyclic ketene acetals with acid chlorides and acid catalyzed olefination reactions in bio-oil. In first four chapters, reactions of in situ generated cyclic ketene acetals were explored. Highly functionalized heterocycles such as pyrrollo-[1,2-c]imidazolediones, were synthesized in one-pot reactions of 2-alkylimidazoles or 2-methylbenzimidazoles with 1,3-diacid chlorides. Some reactions proceed through in situ generated cyclic-N,N′-ketene acetal intermediates. 2-Alkylimidazoles and 2-methylbenzimidazole can be considered as tridentate nucleophiles in these reactions that can give four consecutive attacks on electrophiles which ultimately generate new heterocycles. Reactions of substituted oxazoles and thiazoles with different acid chlorides in the presence of different bases were explored. Arylvinyl esters of substituted benzoic acids containing substituted oxazoles or thiazoles were formed when aroyl chlorides were used. Most reactions occurred through in situ generated cyclic ketene acetals. Reactions of 2-methylbenzoxazole and 5-phenyl-2-methylbenzoxazole with acid chlorides and base in THF generated a series of ortho-amidoesters. All of these reactions showed that aromatic heterocycles based in situ generated cyclic ketene acetals could be used to make highly functionalized heterocycles under mild conditions. These one-pot reactions generated various heterocycles, which might have useful bioactivities. For example, arylvinyl esters of substituted benzoic acids have been reported to show insecticidal activities. The last two chapters describe the olefinations of bio-oil and model bio-oil compounds using acid catalysts. Two different branched olefins were used, representative of those available at petroleum refineries. Amberlyst-15 and Nafion NR-50 were used as heterogeneous acid catalysts. The acid catalyzed olefination of bio-oil was explored using an excess of 1- octene. Some olefinations were performed in the presence of ethanol. Ethanol was used to make the olefin and bio-oil phases partially miscible. Acid catalyzed olefination of raw bio-oil induced some changes in the resulting bio-oil by generating variety of alcohols, ethers and oligomeric mixtures of the starting olefin. Olefination with excess 1-octene showed the decrease of the water content and the acid value and increase of the heating value of the bio-oil. Thus, the acid catalyzed olefination of bio-oil can be considered as a potential bio-oil upgrading technique

Uranium Adsorbent Fibers Prepared by Atom-Transfer Radical Polymerization from Chlorinated Polypropylene and Polyethylene Trunk Fibers

Seawater contains a large amount of uranium (∼4.5 billion tons) which can serve as a nearly limitless supply for an energy source. However, to make the recovery of uranium from seawater economically feasible, lower manufacturing and deployment costs are desirable, and good solid adsorbents must have high uranium uptake, reusability, and high selectivity toward uranium. In this study, atom-transfer radical polymerization (ATRP), without the high-cost radiation-induced graft polymerization, was used for grafting acrylonitrile and <i>tert</i>-butyl acrylate from a new class of trunk fibers, forming adsorbents in a readily deployable form. The new class of trunk fibers was prepared by the chlorination of polypropylene (PP) round fiber, hollow-gear PP fiber, and hollow-gear polyethylene fiber. During ATRP, degrees of grafting (d.g.) varied according to the structure of active chlorine sites on trunk fibers and ATRP conditions, and the d.g. as high as 2570% was obtained. Resulting adsorbent fibers were evaluated in U-spiked simulated seawater, and the maximum adsorption capacity of 146.6 g U/kg, much higher than that of a standard adsorbent Japan Atomic Energy Agency fiber (75.1 g/kg), was obtained. This new type of trunk fiber can be used for grafting a variety of uranium-interacting ligands, including designed ligands that are highly selective toward uranium