EP-3676300-B1 - OLEFIN POLYMERIZATION CATALYST

Inventors

• MARIN, VLADIMIR P.
• HINTOLAY, Ahmed
• O'REILLY, NEIL J.

Dates

Publication Date

20260513

Application Date

20180823

Claims (12)

1. A process for preparing a solid pre-catalyst component for use in olefinic polymerization, the process comprising: dissolving anhydrous magnesium chloride in an alcohol to form a first solution and adjusting the moisture level of the first solution by adding water to the first solution to form a first solution having a water content of 25 mmol water/mol MgCl 2 to 50 mmol water/mol MgCl 2 , contacting the first solution with a first titanium compound to form the solid pre-catalyst component; and treating the solid pre-catalyst component with a hydrocarbon or halogenated hydrocarbon solvent, optionally containing a second titanium compound; wherein the alcohol is selected from the group consisting of ethanol, 1-propanol, 2-propanol, l-butanol, 2-butanol, 2-methyl-2-propanol, l-pentanol, 2-pentanol, l-hexanol, l-heptanol, l-octanol, 2-ethyl hexanol, and mixtures thereof, and wherein the first and second titanium compounds are selected from the group consisting of titanium tetrahalides, alkoxytitanium trihalides, dialkoxytitanium dihalides, trialkoxytitanium monohalides, and tetraalkoxytitaniums.
2. The process of Claim 1 further comprising adding to the first solution a hydrocarbon, a siloxane, an aluminum alkoxide, or a mixture of any two or more thereof to form a second solution.
3. The process of Claim 1 further comprising adding to the first solution a hydrocarbon, a siloxane, and an aluminum alkoxide to form a second solution.
4. The process of Claim 1 with the proviso that no aluminum oxide compounds are present during the dissolving the magnesium chloride in the alcohol.
5. The process of Claim 1 further comprising contacting the first solution with an internal electron donor concurrently with, or subsequent to, dissolving the magnesium chloride in the alcohol.
6. The process of Claim 5, wherein contacting the first solution with the internal electron donor and contacting the first solution with the first titanium compound in the second solvent to form the solid pre-catalyst component occur simultaneously.
7. The process according to any one of Claims 2-6, wherein the aluminum alkoxide compound is added and is selected from the group consisting of aluminum methoxide, aluminum ethoxide, aluminum isopropoxide, and mixtures of any two or more thereof.
8. The process according to any one of the preceding Claims, wherein the first titanium compound is a titanium halide, a titanium alkoxide, or a titanium alkoxychloride.
9. The solid pre-catalyst component obtainable by the process of any one of Claims 1-8.
10. A process of polymerizing or copolymerizing an olefin, the process comprising contacting the solid pre-catalyst component of Claim 9 with an organoaluminum activating agent and the olefin.
11. The process of Claim 10, wherein the organoaluminum activating agent is triethylaluminum, triisobutylaluminum, tri-n-octylaluminum, or a mixture of any two or more thereof.
12. The process of Claim 11, wherein the olefin is ethylene, propylene, l-butylene, 1-methyl-1 -pentene, l-hexene, and l-octene.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the benefit of priority to US Patent Application No. 62/551,378, filed on August 29, 2017. FIELD The present technology is generally related to polyolefin catalysts. More specifically, the technology is related to a process for the preparation of MgCl2-supported olefin polymerization catalysts. BACKGROUND Polyolefins are a class of polymers derived from simple olefins. Known methods of making polyolefins involve the use of Ziegler-Natta polymerization catalysts. These catalysts polymerize vinyl monomers using a transition metal halide to provide a polymer with a highly isotactic stereochemical configuration. One type of a catalyst system includes a solid pre-catalyst component, having a magnesium dihalide (generally, a magnesium chloride) on which are supported a titanium compound and an internal electron donor compound. In order to maintain the high selectivity for an isotactic polymer product, a variety of internal electron donor compounds must be added during the pre-catalyst synthesis. Prior the polymerization reaction, the oxidation state of the titanium compound is reduced in presence of an aluminum alkyl to form the catalyst. It is generally understood that Ziegler-Natta polymerization catalysts are extremely sensitive to even small amounts of water, which can "poison" the catalyst and reduce polymer productivity. Accordingly, most procedures to prepare the solid pre-catalyst component go to great lengths to exclude water or dry the reagents during or prior to preparation of the pre-catalyst component. Without being bound by theory, the present inventors have found that inclusion of water during catalyst preparation acts as a promoter for the Ziegler-Natta MgCl2 based catalyst to improve the catalyst activity and catalyst morphology. US 9,598,509 describes a solid adduct comprising magnesium chloride and ethanol in which the moles of ethanol per mole of magnesium chloride range from 2 to 5 and in which the ratio between the average pore radius measured in Angstrom of said adduct, determined by mercury porosity, and the moles of ethanol, is higher than 500. US 2011/294970 describes solid catalyst components comprising a reaction product of a titanium compound, a magnesium compound, an alcohol, an aluminum alkoxide, a siloxane mixture, and a maleate derivative; and catalyst systems comprising the solid catalyst components and organoaluminum compounds. Also described are methods of making the solid catalyst components and the catalyst systems, and methods of polymerizing or copolymerizing ethylene using the catalyst systems. Rahbar et al., Catalysis Letters, 145, 1186-1195 (2015) describes the effect of water on supported Ziegler-Natta catalysts and optimization of the operating conditions by response surface methodology. SUMMARY In one aspect, a process is provided for preparing a solid pre-catalyst component for use in olefinic polymerization, the process including dissolving anhydrous magnesium chloride in an alcohol to form a first solution and adjusting the moisture level of the first solution by adding water to the first solution to form a first solution having a water content 25 mmol water/mol MgCl2 to 50 mmol water/mol MgCl2; contacting the first solution with a first titanium compound to form the solid pre-catalyst component; and treating the solid pre-catalyst component with a hydrocarbon or halogenated hydrocarbon solvent, optionally containing a second titanium compound; wherein the alcohol is selected from the group consisting of ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, 1-pentanol, 2-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl hexanol, and mixtures thereof; and wherein the first and second titanium compounds are selected from the group consisting of titanium tetrahalides, alkoxytitanium trihalides, dialkoxytitanium dihalides, trialkoxytitanium monohalides, and tetraalkoxytitaniums. In some embodiments, the process further includes adding to the first solution a hydrocarbon, a siloxane, an aluminum alkoxide, or a mixture of any two or more thereof In some embodiments, the process further includes adding to the first solution a hydrocarbon, a siloxane, and an aluminum alkoxide. However, any of the above embodiments may, in some instances, be limited by the proviso that no hydrocarbons are present during the dissolving the magnesium chloride in the alcohol. In some embodiments, the proviso that no alkylaluminum compounds are present during the dissolving the magnesium chloride in the alcohol. In some embodiments, the process further includes contacting the first solution with an internal electron donor concurrently with, or subsequent to, dissolving the magnesium chloride in the alcohol. In some embodiments, contacting the first solution with the internal electron donor and contacting the first solution with the first titanium compound in the second solvent to form the solid pre-ca