Vinylidene olefin process Patent #: 4658078
ApplicationNo. 066890 filed on 05/25/1993
US Classes:526/160, Transition metal bonded to carbon atom502/152, Organic compound including carbon-metal bond526/170, Transition metal bonded to carbon atom526/943POLYMERIZATION WITH METALLOCENE CATALYSTS
ExaminersPrimary: Schofer, Joseph L.
Assistant: Wu, David W.
Attorney, Agent or Firm
Foreign Patent References
International ClassC08F 004/642
AbstractSyndiospecific catalysts and processes for the syndiotactic propagation of a polymer chain derived from an ethylenically unsaturated monomer which contains 3 or more carbon atoms or is a substituted vinyl compound. The catalysts comprise an unbalanced metallocene cation having sterically dissimilar ring structures joined to a positively charged coordinating transition metal atom and a stable noncoordinating counter anion for the metallocene cation. Both ring structures are substituted cyclopentadienyl rings and one is sterically different from the other. Both are in a stereorigid relationship to the coordinating transition metal atom to prevent rotation of the rings by direct stearic hindrence between the ring structures. The catalyst is contacted with a C3+ alpha olefin or other ehtyleically unsaturated compound in a polymerization reaction zone and maintained in contact with the catalyst in the reaction zone under polymerization conditions to produce a syndiotactic polymer.
Field of SearchTransition metal bonded to carbon atom