High porosity fluorided silica-coated alumina activator-supports and uses thereof in metallocene-based catalyst systems for olefin polymerization
Fluorided silica-coated alumina activator-supports have a bulk density from 0.15 to 0.37 g/mL, a total pore volume from 0.85 to 2 mL/g, a BET surface area from 200 to 500 m 2 /g, an average pore diameter from 10 to 25 nm, and from 80 to 99% of pore volume in pores with diameters of greater than 6 nm. Methods of making the fluorided silica-coated alumina activator-supports and using the fluorided silica-coated aluminas in catalyst compositions and olefin polymerization processes also are described. Representative ethylene-based polymers produced using the compositions and processes have a melt index of 0.1 to 10 g/10 min and a density of 0.91 to 0.96 g/cm 3 , and contain from 70 to 270 ppm solid oxide and from 2 to 18 ppm fluorine.
1. A catalyst composition comprising:
a metallocene compound,
a fluorided silica-coated alumina having:
a bulk density from 0.15 to 0.37 g/mL;
a total pore volume from 0.85 to 2 mL/g;
a BET surface area from 200 to 500 m 2 /g; and
an average pore diameter from 10 to 25 nm and/or from 80 to 99% of pore volume in pores with diameters of greater than 6 nm; and
an optional co-catalyst.
2. The catalyst composition of claim 1 , wherein the catalyst composition comprises one metallocene compound.
3. The catalyst composition of claim 1 , wherein the catalyst composition comprises two or more metallocene compounds.
4. An olefin polymerization process, the process comprising contacting the catalyst composition of claim 1 with an olefin monomer and an optional olefin comonomer in a polymerization reactor system under polymerization conditions to produce an olefin polymer.
5. The process of claim 4 , wherein:
the catalyst composition is contacted with ethylene and an olefin comonomer comprising 1-butene, 1-hexene, 1-octene, or a mixture thereof; and
the polymerization reactor system comprises a loop slurry reactor, a fluidized bed reactor, a solution reactor, or a combination thereof.
6. The catalyst composition of claim 1 , wherein the fluorided silica-coated alumina contains:
from 10 to 80 wt. % silica, based on a weight of silica-coated alumina; and
from 0.5 to 18 wt. % F., based on a weight of the fluorided silica-coated alumina.
7. The catalyst composition of claim 1 , wherein the fluorided silica-coated alumina has an average (d50) particle size from 30 to 150 microns.
8. The catalyst composition of claim 1 , wherein:
the bulk density is from 0.17 to 0.3 g/mL;
the total pore volume is from 0.9 to 1.5 mL/g;
the BET surface area is from 250 to 450 m 2 /g;
the average pore diameter is from 10 to 20 nm; and
from 83 to 98% of the pore volume is in pores with diameters of greater than 6 nm.
9. The catalyst composition of claim 1 , wherein:
from 9.5 to 30% of the pore volume is in pores with diameters of greater than 20 nm;
from 3.5 to 15% of the pore volume is in pores with diameters of greater than 40 nm;
the fluorided silica-coated alumina has a pore volume of from 0.7 to 1.6 mL/g in pores with diameters of greater than 6 nm; and
the fluorided silica-coated alumina has a pore volume of from 0.09 to 0.4 mL/g in pores with diameters of greater than 20 nm.
10. The catalyst composition of claim 1 , wherein:
from 65 to 98% of surface area is in pores with diameters of greater than 6 nm;
from 19.5 to 55% of surface area is in pores with diameters of greater than 10 nm;
the fluorided silica-coated alumina has a surface area of from 250 to 475 m 2 /g in pores with diameters of greater than 6 nm; and
the fluorided silica-coated alumina has a surface area of from 78 to 200 m 2 /g in pores with diameters of greater than 10 nm.
11. The catalyst composition of claim 1 , wherein:
the catalyst composition comprises the co-catalyst; and
from 80 to 99% of the pore volume is in pores with diameters of greater than 6 nm.
12. The catalyst composition of claim 11 , wherein from 83 to 98% of the pore volume is in pores with diameters of greater than 6 nm.
13. The catalyst composition of claim 12 , wherein the catalyst composition comprises two or more metallocene compounds.
14. The catalyst composition of claim 1 , wherein:
the catalyst composition comprises the co-catalyst; and
the average pore diameter of the fluorided silica-coated alumina is from 10 to 25 nm.
15. The catalyst composition of claim 14 , wherein:
the co-catalyst comprises an organoaluminum compound; and
the metallocene compound comprises an unbridged zirconium or hafnium based metallocene compound containing two cyclopentadienyl groups, two indenyl groups, or a cyclopentadienyl and an indenyl group.
16. The catalyst composition of claim 14 , wherein:
the co-catalyst comprises an organoaluminum compound; and
the metallocene compound comprises a bridged zirconium or hafnium based metallocene compound with a cyclopentadienyl group and a fluorenyl group.
17. The catalyst composition of claim 14 , wherein the fluorided silica-coated alumina contains:
from 10 to 80 wt. % silica, based on a weight of silica-coated alumina; and
from 0.5 to 18 wt. % F., based on a weight of the fluorided silica-coated alumina.
18. The catalyst composition of claim 14 , wherein the fluorided silica-coated alumina has an average (d50) particle size from 30 to 150 microns.
19. The catalyst composition of claim 14 , wherein:
the bulk density is from 0.17 to 0.3 g/mL;
the total pore volume is from 0.9 to 1.5 mL/g;
the BET surface area is from 250 to 450 m 2 /g; and
from 83 to 98% of the pore volume is in pores with diameters of greater than 6 nm.
20. The catalyst composition of claim 14 , wherein:
from 9.5 to 30% of the pore volume is in pores with diameters of greater than 20 nm;
from 3.5 to 15% of the pore volume is in pores with diameters of greater than 40 nm;
the fluorided silica-coated alumina has a pore volume of from 0.7 to 1.6 mL/g in pores with diameters of greater than 6 nm; and
the fluorided silica-coated alumina has a pore volume of from 0.09 to 0.4 mL/g in pores with diameters of greater than 20 nm.
21. The catalyst composition of claim 14 , wherein:
from 65 to 98% of surface area is in pores with diameters of greater than 6 nm;
from 19.5 to 55% of surface area is in pores with diameters of greater than 10 nm;
the fluorided silica-coated alumina has a surface area of from 250 to 475 m 2 /g in pores with diameters of greater than 6 nm; and
the fluorided silica-coated alumina has a surface area of from 78 to 200 m 2 /g in pores with diameters of greater than 10 nm.
22. A process to produce a fluorided silica-coated alumina, the process comprising contacting a fluoriding agent with a silica-coated alumina to produce the fluorided silica-coated alumina, wherein the silica-coated alumina has:
a bulk density from 0.15 to 0.37 g/mL;
a total pore volume from 1.1 to 2.5 mL/g;
a BET surface area from 250 to 600 m 2 /g; and
an average pore diameter from 10 to 25 nm.