極性官能基を置換基に含むビニルエーテルのカチオン重合における副反応の検証 : 官能基の種類と数の影響

概要

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To study effects of the sort and number of functional groups of vinyl ether monomers on the tendency of the side reaction in the HCl/ZnCl2-initiated controlled cationic polymerizations,2-(2-vinyloxyethoxy)ethyl phenylcarbamate(VEEPC)and 2-[2-(2-vinyloxyethoxy)ethoxy]ethyl phenylcarbamate(VEEEPC)with both an oxyethylene chain and a urethane group were polymerized in CH2CL2 at -30℃. Along with the formation of the long-lived polymers,the oligomeric products were produced during the polymerizations. The HCl/ZnCl2-initiated polymerization of 2-(2-metoxyethoxy)ethyl vinyl ether(MEEVE)with an oxyethylene chain and n-butyl vinyl ether(NBVE)were carried out under the same reaction conditions,where MEEVE formed a small amount of the similar oligomeric products,but NBVE did not form any oligomeric side products:the order of the amount of oligomers formed VEEEPC > VEEPC > MEEVE > NBVE(no oligomers). NBVE also induced perfect living polymerization even in the presence of the urethane model compound CH3-CH2-O-CH2-CH2-O-CO-NH-C6H5 under otherwise the same reaction conditions. Therefore,the side reaction occurred only when the functional groups were incorporated in the vinyl ether monomers. The reason for the side reaction are most likely due to the destabilization of growing carbocations by electron-withdrawing functional groups in their side chain and/or intramolecular through-space effects of the pendant fanctional chains.
福井大学の論文
2008-03-31