Process and catalyst for producing syndiotactic polymers
Patent 5292838 Issued on March 8, 1994. Estimated Expiration Date: 
May 25, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
May 25, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3135809 3305538 3364190 Vinylidene olefin process Patent #: 4658078 InventorAssigneeApplicationNo. 066890 filed on 05/25/1993US 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 CATALYSTSExaminersPrimary: Schofer, Joseph L.Assistant: Wu, David W. Attorney, Agent or FirmForeign Patent References
International ClassC08F 004/642AbstractSyndiospecific 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.Other References
Field of SearchTransition metal bonded to carbon atom |
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