Methods of preparing a catalyst
A method comprising a) drying a support material comprising silica at temperature in the range of from about 150° C. to about 220° C. to form a dried support; b) contacting the dried support with methanol to form a slurried support; c) subsequent to b), cooling the slurried support to a temperature of less than about 60° C. to form a cooled slurried support; d) subsequent to c), contacting the cooled slurried support with a titanium alkoxide to form a titanated support; and e) thermally treating the titanated support by heating to a temperature of equal to or greater than about 150° C. for a time period of from about 5 hours to about 30 hours to remove the methanol and yield a dried titanated support.
1. A method comprising:
a) drying a support material at a temperature in a range of from about 150° C. to about 220° C. to form a dried support;
b) contacting the dried support with a solvent to form a slurried support;
c) subsequent to b), cooling the slurried support to a temperature of less than about 50° C. to form a cooled support;
d) contacting the cooled support with a titanium-containing compound to form a titanated support;
e) contacting the titanated support with a chromium-containing compound to form a chrominated support;
f) thermally treating the chrominated support by increasing the temperature of the chrominated support to a boiling point of the solvent;
g) prior to reaching the boiling point of the solvent, contacting the chrominated support with a water in an amount ranging from about 0.1 moles to about 10 moles per mole of titanium to produce a mixture; and
h) thermally treating the mixture by heating the mixture to a temperature of equal to or greater than about 150° C. for a time period of from about 5 hours to about 30 hours to yield a precatalyst.
2. The method of claim 1 further comprising calcining the precatalyst at a temperature in the range of from about 400° C. to about 1000° C. for a time period of from about 30 minutes to about 24 hours to form a polymerization catalyst.
3. The method of claim 2 wherein the titanium-containing compound is present in an amount of from about 0.1 wt. % to about 10 wt. % by total weight of the polymerization catalyst.
4. The method of claim 2 wherein the chromium-containing compound is present in an amount of from about 0.1 wt. % to about 10 wt. % by total weight of the polymerization catalyst.
5. The method of claim 1 wherein the support material is dried for a time period ranging from about 5 hours to about 24 hours.
6. The method of claim 5 wherein the solvent is present in an amount ranging from about 2 times to about 3 times weight of the dried support.
7. The method of claim 6 wherein the solvent comprises methanol having a water content of less than about 0.1 wt. %.
8. The method of claim 7 wherein the titanium-containing compound comprises titanium n-propoxide and the chromium-containing compound comprises basic chromium acetate.
9. The method of claim 8 further comprising calcining the precatalyst at a temperature in the range of from about 400° C. to about 1000° C. for a time period of from about 30 minutes to about 24 hours to form a polymerization catalyst, wherein the titanium-containing compound is present in an amount of from about 0.1 wt. % to about 10 wt. % by total weight of the polymerization catalyst and wherein the chromium-containing compound is present in an amount of from about 0.1 wt. % to about 10 wt. % by total weight of the polymerization catalyst.
10. The method of claim 5 wherein the solvent comprises methanol having a water content of less than about 0.1 wt. %.
11. The method of claim 10 wherein the titanium-containing compound comprises titanium n-propoxide and the chromium-containing compound comprises basic chromium acetate.
12. The method of claim 1 wherein the solvent is present in an amount ranging from about 2 times to about 3 times weight of the dried support.
13. The method of claim 12 wherein the solvent comprises methanol having a water content of less than about 0.1 wt. %.
14. The method of claim 13 wherein the titanium-containing compound comprises titanium n-propoxide and the chromium-containing compound comprises basic chromium acetate.
15. The method of claim 1 wherein step (d) is performed under mixing conditions for efficient dispersal of the titanium-containing compound.
16. The method of claim 1 wherein the solvent comprises methanol having a water content of less than about 0.1 wt. %.
17. The method of claim 1 wherein the support material comprises a silica.
18. The method of claim 17 wherein the silica is characterized by a surface area of from about 250 m 2 /g to about 1000 m 2 /g and a pore volume of greater than about 1.0 cm 3 /g.
19. The method of claim 1 wherein the titanium-containing compound comprises titanium n-propoxide.
20. The method of claim 1 wherein the chromium-containing compound comprises basic chromium acetate.