Aqueous methods for titanating a chromium/silica catalyst with an alkali metal
Methods for making titanated silica supports, titanated chromium/silica pre-catalysts, and activated titanated chromium/silica catalysts are disclosed in which hydrogen peroxide and an alkali metal precursor are used during catalyst preparation. Resulting titanated chromium/silica pre-catalysts often contain silica, 0.1 to 5 wt. % chromium, 0.1 to 10 wt. % titanium, and less than or equal to 4 wt. % carbon, and further contain an alkali metal or zinc at a molar ratio of alkali metal:titanium or zinc:titanium from 0.02:1 to 3:1 and/or at an amount in a range from 0.01 to 2 mmol of alkali metal or zinc per gram of the silica. High melt index potential activated titanated chromium/silica catalysts can be used to polymerize olefins to produce, for example, ethylene based homopolymers and copolymers having HLMI values of greater than 30 g/10 min.
1. A titanated silica support consisting of:
a silica;
from 0.1 to 10 wt. % titanium;
from 0.5 to 12 wt. % water;
less than or equal to 3 wt. % carbon; and
an alkali metal and/or zinc;
wherein a molar ratio of the alkali metal to the titanium and/or the zinc to the titanium is from 0.05:1 to 3:1; and/or
wherein an amount of the alkali metal and/or the zinc is in a range from 0.04 to 2 mmol of the alkali metal or the zinc per gram of the silica.
2. The titanated silica support of claim 1 , wherein the molar ratio of the alkali metal to the titanium or the zinc to the titanium is from 0.12:1 to 2.2:1 and/or the amount of the alkali metal or the zinc is in range from 0.1 to 1.2 mmol of the alkali metal or the zinc per gram of the silica.
3. The titanated silica support of claim 1 , wherein the titanated silica support consists of the alkali metal and the alkali metal comprises sodium.
4. The titanated silica support of claim 3 , wherein:
at least a portion of the sodium is bound to the titanium; and/or
at least a portion of the sodium is present as sodium titanate.
5. The titanated silica support of claim 1 , wherein the molar ratio of the alkali metal to the titanium or the zinc to the titanium is from 0.12:1 to 2.2:1.
6. The titanated silica support of claim 5 , wherein the titanated silica support consists of:
the silica;
from 1 to 6 wt. % of the titanium;
from 0.5 to 12 wt. % of the water;
less than or equal to 2 wt. % of the carbon; and
the alkali metal and/or the zinc.
7. The titanated silica support of claim 6 , wherein the titanated silica support consists of the alkali metal and the alkali metal comprises sodium.
8. The titanated silica support of claim 7 , wherein the molar ratio of the sodium to the titanium is from 0.2:1 to 1.8:1.
9. The titanated silica support of claim 6 , wherein the amount of the alkali metal or the zinc is in range from 0.1 to 1.2 mmol of the alkali metal or the zinc per gram of the silica.
10. The titanated silica support of claim 9 , wherein the titanated silica support consists of the alkali metal and the alkali metal comprises sodium.
11. The titanated silica support of claim 10 , wherein the amount of the sodium is in a range from 0.15 to 0.9 mmol of the sodium per gram of the silica.
12. A titanated chromium/silica pre-catalyst consisting of:
the titanated silica support of claim 1 ; and
from 0.1 to 5 wt. % chromium.
13. The titanated chromium/silica pre-catalyst of claim 12 , wherein at least 75 wt. % of the chromium is present in an oxidation state of three or less.
14. The titanated chromium/silica pre-catalyst of claim 12 , wherein the molar ratio of the alkali metal to the titanium or the zinc to the titanium is from 0.2:1 to 1.8:1.
15. The titanated chromium/silica pre-catalyst of claim 14 , wherein the amount of the alkali metal or the zinc is in a range from 0.1 to 1.2 mmol of the alkali metal or the zinc per gram of the silica.
16. The titanated chromium/silica pre-catalyst of claim 14 , wherein:
the titanated chromium/silica pre-catalyst consists of the alkali metal and the alkali metal comprises sodium; and
the amount of the sodium is in the range from 0.15 to 0.9 mmol of the sodium per gram of the silica.
17. A titanated silica support consisting of:
a silica;
from 0.1 to 10 wt. % titanium;
from 0.5 to 12 wt. % water;
less than or equal to 3 wt. % carbon;
from 0.01 to 1.5 wt. % nitrogen; and
an alkali metal and/or zinc;
wherein a molar ratio of the alkali metal to the titanium and/or the zinc to the titanium is from 0.05:1 to 3:1; and/or
wherein an amount of the alkali metal and/or the zinc is in a range from 0.04 to 2 mmol of the alkali metal or the zinc per gram of the silica.
18. The titanated silica support of claim 17 , wherein:
the molar ratio of the alkali metal to the titanium or the zinc to the titanium is from 0.2:1 to 1.8:1; and
the amount of the alkali metal or the zinc is in the range from 0.15 to 0.9 mmol of the alkali metal or the zinc per gram of the silica.
19. A titanated chromium/silica pre-catalyst consisting of:
the titanated silica support of claim 17 ; and
from 0.1 to 5 wt. % chromium.
20. The titanated chromium/silica pre-catalyst of claim 19 , wherein:
at least 75 wt. % of the chromium is present in an oxidation state of three or less;
the molar ratio of the alkali metal to the titanium or the zinc to the titanium is from 0.2:1 to 1.8:1; and
the amount of the alkali metal or the zinc is in the range from 0.15 to 0.9 mmol of the alkali metal or the zinc per gram of the silica.