Rare earth homogeneous catalysts for the ring-opening polymerization and copolymerization of strained-ring olefins

摘要

The organolanthanide hydrides (Cp'.sub.2 LnH).sub.2 (Cp'=&eegr; .sup.5 - Me.sub.5 C.sub.5 ;Ln=Sm,Lu) rapidly catalyze the copolymerization of methylenecyclopropane and ethylene to cleanly yield high molecular weight polyolefins of microstructure {[CH.sub.2 CH.sub.2 ]. sub.x [CH.sub.2 CH. sub.2 C(CH.sub.2)].sub.y }n via sequential olefin insertion and ring- opening/&bgr;-alkyl shift processes. Homopolymerization of methylenecyclopropane likewise cleanly yields polymers of the structure [CH.sub.2 CH.sub.2 C(CH.sub.2)].sub.n.