Process for producing syndiotactic polyolefins

摘要: The invention provides a metallocene catalyst for use in preparing syndiotactic polyolefins. comprises bridged which one of the cyclopentadienyl rings is substituted substantially different manner from other ring. It was discovered that this type highly syndiospecific, and it also produces polymer with novel microstructure. further includes or more catalysts polymerization process. generally described by formula R"(CpR.sub.n)(CpR'.sub.m)MeQ.sub.k wherein each Cp ring; R n R' m same hydrocarbyl radicals having 1-20 carbon atoms; R" structural bridge between two imparting stereorigidity to catalyst; Me group 4b, 5b, 6b metal Periodic Table Elements; Q radical atoms halogen; 0≦k≦3; 0≦n≦4; 1≦m≦4; selected such (CpR' ) sterically ring than (CpR ).