Single-site catalysts for olefin polymerization
AssigneeEquistar Chemicals, LP
InventorJia-Chu Liu
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Abstract
A method for making single-site catalysts useful for olefin polymerization is disclosed. A nitrogen-functional heterocycle is first deprotonated with an alkyllithium compound, followed by reaction of this anionic ligand precursor with about 0.5 equivalents of a Group 4 transition metal tetrahalide in a hydrocarbon solvent at a temperature greater than about 10° C. to give an organometallic complex-containing mixture. When combined with exceptionally low levels of an activator (e.g., methyl alumoxane), the mixture actively polymerizes olefins to give polymers with a favorable balance of physical properties, including low density and narrow molecular weight distribution.
Claims15
A method which comprises:
- (a) deprotonating a compound selected from the group consisting of indoles, carbazoles, 8-quinolinols, 2-pyridinols, and mixtures thereof, with an alkyllithium compound to produce an anionic ligand precursor;
- and
- (b) reacting the anionic ligand precursor with about 0.5 equivalents of a Group 4 transition metal tetrahalide at a temperature greater than about 10° C. in the presence of a hydrocarbon solvent to produce an organometallic complex-containing mixture.
A method which comprises:
- (a) deprotonating a compound selected from the group consisting of indoles, carbazoles, 8-quinolinols, 2-pyridinols, and mixtures thereof, with an alkyllithium compound to produce an anionic ligand precursor;
- and
- (b) reacting the anionic ligand precursor with about 1 equivalent of an indenyl Group 4 transition metal trihalide at a temperature greater than about 10° C. in the presence of a hydrocarbon solvent to produce an organometallic complex-containing mixture.
Dependencies are inferred from the claim text.