Heterogeneous Ziegler-Natta catalysts with fluorided silica-coated alumina
Catalyst systems containing a Ziegler-Natta catalyst component are disclosed. Such catalyst systems can contain a co-catalyst and a supported catalyst containing a fluorided silica-coated alumina, a magnesium compound, and vanadium and/or tetravalent titanium.
1. A process to produce a supported catalyst, the process comprising:
(i) contacting:
(a) a fluorided silica-coated alumina;
(b) a magnesium compound; and
(c) a titanium (IV) compound and/or vanadium compound; and
(ii) forming the supported catalyst.
2. The process of claim 1 , wherein step (i) is conducted in a non-polar solvent.
3. The process of claim 1 , wherein step (i) is conducted in a polar aprotic solvent.
4. The process of claim 1 , wherein the fluorided silica-coated alumina comprises from about 20 to about 45 wt. % silica and from about 2 to about 15 wt. % fluorine.
5. The process of claim 1 , wherein the supported catalyst comprises from about 0.5 to about 7 wt. % magnesium.
6. The process of claim 5 , wherein the magnesium compound is not a reducing agent.
7. The process of claim 1 , wherein the supported catalyst comprises from about 0.5 to about 10 wt. % titanium.
8. The process of claim 7 , wherein the supported catalyst is substantially free of Ti(III).
9. A catalyst composition comprising a co-catalyst and a supported catalyst comprising:
(a) a fluorided silica-coated alumina;
(b) a magnesium compound; and
(c) titanium (IV) and/or vanadium.
10. The composition of claim 9 , wherein:
the fluorided silica-coated alumina comprises from about 20 to about 45 wt. % silica and from about 3 to about 12 wt. % fluorine;
the supported catalyst comprises from about 0.5 to about 3 wt. % magnesium, and the magnesium compound is not a reducing agent; and
the supported catalyst comprises from about 0.5 to about 10 wt. % titanium, and the supported catalyst is substantially free of Ti(III).
11. The composition of claim 10 , wherein the supported catalyst comprises a titanium (IV) compound comprising a titanium halide, a titanium alkoxide, an alkoxytitanium halide, or a combination thereof.
12. The composition of claim 9 , wherein the supported catalyst comprises a magnesium halide, a magnesium alkoxide, an alkoxymagnesium halide, or a combination thereof.
13. The composition of claim 9 , wherein the supported catalyst further comprises from about 1 to about 50 ppm THF by weight.
14. The composition of claim 9 , wherein a weight ratio of the co-catalyst to the supported catalyst is in a range from about 3:1 to about 1:100.
15. The composition of claim 9 , wherein the catalyst composition has a catalyst activity greater than about 2,000 g/g/hr, under slurry polymerization conditions, with a triisobutylaluminum co-catalyst, using isobutane as the diluent, at a polymerization temperature of 90° C. and a reactor pressure of 400 psig.
16. An olefin polymerization process, the process comprising contacting the catalyst composition of claim 9 with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.
17. The process of claim 16 , wherein the catalyst composition is contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixture thereof.
18. The process of claim 16 , wherein the polymerization reactor system comprises a slurry reactor, a gas-phase reactor, a solution reactor, or a combination thereof.
19. The process of claim 16 , wherein the olefin polymer is an ethylene/alpha-olefin copolymer.
20. The process of claim 19 , wherein the ethylene/alpha-olefin copolymer has less than about 0.005 long chain branches per 1000 total carbon atoms and/or has a substantially constant short chain branch distribution.