Stereospecific living Ziegler-Natta polymerization via rapid and reversible chloride degenerative transfer between active and dormant sites.
The successful realization of a stereospecific chloride degenerative transfer living Ziegler-Natta polymerization process that provides isotactic polyolefins of narrow polydispersity (Mw/Mn </= 1.05) is documented. Variable-temperature NMR studies confirm the configurational stability of all species with respect to metal-centered epimerization and large magnitudes for both kbeta and k-beta. Additional kinetic analyses with an increasing concentration of the dormant state establish that kbeta is larger than k-beta. Finally, [Et3Si][B(C6F5)4] has been shown to be an effective substoichiometric halide abstractor for chloride degenerative transfer Ziegler-Natta polymerization.
Zhang
Yonghui
Y
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.
Sita
Lawrence R
LR