摘要:
The invention relates to substituted monocyclopentadienyl, monoindenyl, monofluorenyl or heterocyclopentadienyl complexes of chromium, molybdenum or tungsten, wherein at least one of the substituents at the cyclopentadienyl ring carries a rigid donor function that is not exclusively linked via sp3 hybridized carbon or silicon atoms. The invention further relates to a method for polymerizing olefins.
摘要:
Catalyst composition comprising a reduced transition metal complex and a cocatalyst, wherein the reduced transition metal complex has structure (I). L1 can be a phenyl group in which at least one of the ortho-positions is substituted with a functional group capable of donating electron density to the transition metal M. L1 can also be a methyl group in which one or more of the alpha-positions is substituted with a functional group capable of donating electron density to the transition metal M.
摘要:
A Group VIB metal-based, ligand-containing olefin polymerization catalyst component can be made by using Group VIB metal trihalide as the starting reagent for the Group VIB metal which process comprises contacting (e.g., in tetrahydrofuran) the Group VIB metal trihalide, such as chromium trichloride, with the ligand reagent or reagents, such as a cyclopentadienyl-containing lithium compound and a lower alkyl-containing lithium compound, in the presence of a sigma donor stabilizing ligand, such as pyridine.
摘要:
The polymerisation of olefins in the gas phase carried out in the presence of a catalyst system comprising (a) a metallocene and (b) an activator is improved by the addition of a lower alkane to the reactor. The preferred alkane is pentane and is preferably added to the reactor as a liquid. The activity of the catalyst system may be improved by the addition of the alkane.
摘要:
Catalyst composition comprising a reduced transition metal complex and a cocatalyst, wherein the reduced transition metal complex has the following structure: L1 can be a phenyl group in which at least one of the ortho-positions is substituted with a functional group capable of donating electron density to the transition metal M. L1 can also be a methyl group in which one or more of the alpha-positions is substituted with a functional group capable of donating electron density to the transition metal M.
摘要:
Disclosed is a catalyst system for the homopolymerization of alpha-olefins having 2-8 carbon atoms, said catalyst system comprising a mixed-valent dimeric Group 6b metal compound catalyst precursor wherein one atom of said Group 6b metal is a cyclopentadienyl Group 6b metal hydrocarbyl complex in which the Group 6b metal has an oxidation state +3 and wherein one atom of said Group 6b metal is a cyclopentadienyl alkaryl complex in which the Group 6b metal has an oxidation state +1, said dimeric Group 6b metal compound being supported on an inorganic support. The catalyst system can contain, in addition, a Group 2 or Group 3 metal-alkyl compound.