The atom transfer radical polymerization of styrene was carried out with an α-haloketone, 2-bromocyclohexanone, as the initiator in the presence of CuBr/Cu/2,2′-bipyridine or CuBr/ N,N,N′,N″,N″-pentamethyldiethyl...The atom transfer radical polymerization of styrene was carried out with an α-haloketone, 2-bromocyclohexanone, as the initiator in the presence of CuBr/Cu/2,2′-bipyridine or CuBr/ N,N,N′,N″,N″-pentamethyldiethylenetriamine catalytic system. The polymerization proceeded in a living fashion with that the number average molecular weight increased linearly with the increase of monomer conversion and the polydispersity was relatively low through the polymerization process, especially with CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine as the catalyst. The initiation efficiency of 2-bromocyclohexanone in both catalysis systems was about 80%. 1H NMR and 13C NMR verified the presence of 2-oxocyclohexyl and bromine atom at the both ends of polystyrene chains respectively, which were derived from the 2-bromocyclohexanone.展开更多
The synthesis of(S)-1-phenyl-1,2-ethanediol was studied in this article.Firstly,1,2-dibromo-1-phenylethane was synthesized with styrene and bromine as starting agents.The effects of some factors,including raw material...The synthesis of(S)-1-phenyl-1,2-ethanediol was studied in this article.Firstly,1,2-dibromo-1-phenylethane was synthesized with styrene and bromine as starting agents.The effects of some factors,including raw materials’ molar ratio,reaction time and solvents,on the yield of 1,2-dibromo-1-phenylethane were examined.Secondly,1-phenyl-1,2-ethanediol was obtained by use of hydrolysis of 1,2-dibromo-1-phenylethane in alkaline medium.The influence of reaction time and medium on the yield of 1-phenyl-1,2-ethanediol was also examined.Under the optimized conditions,the yield of 1,2-dibromo-1-phenylethane was 90.1% while the yield of 1-phenyl-1,2-ethanediol was 78.5%.Finally,(S)-1-phenyl-1,2-ethanediol was received by deracemization of 1-phenyl-1,2-ethanediol employing Candida parapsilosis.The enantiomeric excess of(S)-1-phenyl-1,2-ethanediol was 99% and the conversion was 88%.展开更多
文摘The atom transfer radical polymerization of styrene was carried out with an α-haloketone, 2-bromocyclohexanone, as the initiator in the presence of CuBr/Cu/2,2′-bipyridine or CuBr/ N,N,N′,N″,N″-pentamethyldiethylenetriamine catalytic system. The polymerization proceeded in a living fashion with that the number average molecular weight increased linearly with the increase of monomer conversion and the polydispersity was relatively low through the polymerization process, especially with CuBr/N,N,N′,N″,N″-pentamethyldiethylenetriamine as the catalyst. The initiation efficiency of 2-bromocyclohexanone in both catalysis systems was about 80%. 1H NMR and 13C NMR verified the presence of 2-oxocyclohexyl and bromine atom at the both ends of polystyrene chains respectively, which were derived from the 2-bromocyclohexanone.
文摘The synthesis of(S)-1-phenyl-1,2-ethanediol was studied in this article.Firstly,1,2-dibromo-1-phenylethane was synthesized with styrene and bromine as starting agents.The effects of some factors,including raw materials’ molar ratio,reaction time and solvents,on the yield of 1,2-dibromo-1-phenylethane were examined.Secondly,1-phenyl-1,2-ethanediol was obtained by use of hydrolysis of 1,2-dibromo-1-phenylethane in alkaline medium.The influence of reaction time and medium on the yield of 1-phenyl-1,2-ethanediol was also examined.Under the optimized conditions,the yield of 1,2-dibromo-1-phenylethane was 90.1% while the yield of 1-phenyl-1,2-ethanediol was 78.5%.Finally,(S)-1-phenyl-1,2-ethanediol was received by deracemization of 1-phenyl-1,2-ethanediol employing Candida parapsilosis.The enantiomeric excess of(S)-1-phenyl-1,2-ethanediol was 99% and the conversion was 88%.
