Asymmetric, polymerization

Takeda, Y., Y. Hayakawa, T. Fueno, and J. Furukawa Studies on the Mechanism of the Stereospecific Polymerization Asymmetric-induction Polymerization of Benzofuran by Use of Optically Active Organo-stannic Compounds. Makromolekulare Chem. 83, 234 (1965). 

Tacticity. In addition to the type, number, and sequential arrangement of monomers along the chain, tacticity or the spatial arrangement of substituent groups is also important in determining properties. Three types of steric configurations are possible from polymerizing asymmetric vinyl monomers, as represented with polypropylene in Fig. 14.13 ... 

Yoshio Okamoto was born in Osaka, Japan, in 1941. He received his bachelor (1964), master (1966), and doctorate (1969) degrees from Osaka University, Faculty of Science. He joined Osaka University, Faculty of Engineering Science, as an assistant in 1969, and spent two years (1970— 1972) at the University of Michigan as a postdoctoral fellow with Professor C. G. Overberger. In 1983, he was promoted to Associate Professor, and in 1990 moved to Nagoya University as a professor. His research interest includes stereocontrol in polymerization, asymmetric polymerization, optically active polymers, and enantiomer separation by HPLC. He received the Award of the Society of Polymer Science, Japan, in 1982, the Chemical Society of Japan Award for Technical Development in 1991, the Award of The Chemical Society of Japan (1999), and the Chirality Medal (2001), among others. 

Enzyme immobilization in the sponge of polymeric asymmetric and symmetric membranes has the advantage of a stable immobilized enzyme system along with the improved isolation of enzymatic proteins from immunodefensive system actions, high molecular weight inhibitors and proteolytic enzymes. A suitable choice of membranes based on their separation properties allows substrate molecules to permeate through the membrane while, at the same time, separating undesirable compounds from the enzymatic proteins. 

S.A. McKelvey, W. Koros, Phase separation, vitrification and the manifestation of macrovoids in polymeric asymmetric membranes. Journal of Membrane Science 112 (1996) 29. 

For the synthesis of stereospecific metallocene catalysts for propylene polymerization, C2 symmetric precursors are necessary to obtain a catalyst for isospecific polymerization, and C5 symmetric precursors to produce a catalyst for syndiospecific polymerization. Asymmetric precursors can be used to synthesize metallocene catalysts that produce hemiisotactic and isotactic-stereoblock PP. Farina et al. [7] have proposed an useful classification of metallocene catalysts based on their symmetry (Figure 3). 

Other groups have attempted the synthesis of optically active polymers by using polymeric asymmetric catalysts. For example, Imanishi, Kugimiya, and Higashimura used poly(A -methyl-L-alanine) of various polymerization degrees for the polymerization of L-... 

According to the single-crystal X-ray crystallographic analysis, (tosylimi-noiodo)-o-methoxybenzene 211 (R = Me) has a polymeric, asymmetrically bridged structure similar to that observed for PhINTs (2011CEJ10538). However, in contrast to PhINTs, compound 211 has an additional weak... 

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