Polymerization process
AssigneePhillips Petroleum Company
InventorsJoseph J. Bergmeister, Steven J. Secora, Gerhard K. Guenther, Elizabeth A. Benham, Max P. McDaniel
Life of this patent
Estimating the term…
Abstract
Polymerization processes for ethylene and at least one mono-1-olefin comonomer having from about three to eight carbon atoms per molecule in the presence of a twice-aged catalyst system comprising chromium supported on a silica-titania support and a trialkylboron compound is provided. Novel ethylene copolymers also are produced.
Claims7
A polymerization process comprising contacting under slurry polymerization conditions at a temperature within a range of about 200° F. to about 226° F. (about 93° C. to about 108° C.) in an isobutane diluent:
- a) ethylene monomer;
- b) at least 1 mono-1-olefin comonomer having about three to eight carbon atoms per molecule;
- c) a catalyst system comprising chromium supported on a silica-titania support, wherein said support comprises from about 1 to about 10 weight percent titanium, based on the weight on the support, wherein said catalyst system is aged twice and wherein the first aging is at a substantially neutral pH and wherein the second aging is at an alkaline pH, said catalyst system has a pore volume within a range of about 0.5 to about 1.3 ml/g, a surface area within a range about 150 to 400 m2/g, and said catalyst system has been calcined at a temperature within a range of about 800° F. to about 1300° F. (about 427° C. to about 704° C.);
- d) about 1 to about 6 mg/kg, based on total reactor contents, of a trialkylboron compound;
- and
- e) recovering an ethylene/mono-1-olefin copolymer.
A polymerization process comprising contacting under slurry polymerization conditions at a temperature within a range of about 210° F. to about 220° F. in an isobutane diluent:
- a) ethylene monomer;
- b) 1-hexene comonomer;
- c) a catalyst system comprising chromium supported on a silica-titania support, where in said support comprises from 2 to 8 weight percent titanium, based on the weight on the support, wherein said catalyst system is aged twice and wherein the first aging is at a substantially neutral pH and wherein the second aging is at an alkaline pH, said catalyst system has a pore volume within range of 0.8 to 1.2 ml/g, a surface area within a range of 250 to 350 m2/g, and said catalyst system has been calcined at a temperature within a range of 1100° F. to 1200° F.;
- d) about 2 to about 4 mg/kg, based on total reactor contents, of a triethylboron cocatalyst;
- and
- e) recovering an ethylene/1-hexene copolymer.
Dependencies are inferred from the claim text.