Aqueous methods for titanating a chromium/silica catalyst with an alkali metal

1. A process for preparing a titanated silica support, the process comprising:

(i) contacting water, hydrogen peroxide, an alkali metal precursor and/or a zinc precursor, a titanium precursor, and a silica to form a first mixture;

(ii) contacting the first mixture with a nitrogen-containing compound to form a second mixture;

(iii) subjecting the second mixture to a reaction temperature in a range from 40 to 270° C.;

(iv) isolating a solid fraction from the second mixture and washing the solid fraction; and

(v) drying the solid fraction to form the titanated silica support.

2. The process of claim 1 , wherein:

the silica is a preformed silica; and

the alkali metal precursor in the step (i) comprises sodium.

3. The process of claim 1 , wherein the process further comprises a step of adjusting a pH of the first mixture to within a range from 3 to 12.

4. A process for preparing a titanated chromium/silica pre-catalyst, the process comprising:

performing the process for preparing the titanated silica support of claim 1 ; and

contacting a chromium precursor with the first mixture or the second mixture prior to the step (iv) of the claim 1 .

5. A process for preparing a titanated chromium/silica catalyst, the process comprising:

performing the process for preparing the titanated chromium/silica pre-catalyst of claim 4 ; and

activating the titanated chromium/silica pre-catalyst to form the titanated chromium/silica catalyst.

6. A process for preparing a titanated chromium/silica pre-catalyst, the process comprising:

performing the process for preparing the titanated silica support of claim 1 ; and

contacting a chromium precursor with the solid fraction after isolating the solid fraction from the second mixture in the step (iv) of the claim 1 .

7. A process for preparing a titanated chromium/silica catalyst, the process comprising:

performing the process for preparing the titanated chromium/silica pre-catalyst of claim 6 ; and

activating the titanated chromium/silica pre-catalyst to form the titanated chromium/silica catalyst.

8. The process of claim 1 , wherein:

a molar ratio of the hydrogen peroxide to the titanium precursor is in a range from 0.5:1 to 100:1; and

a molar ratio of the alkali metal precursor or the zinc precursor to the titanium precursor is in a range from 0.1:1 to 300:1.

9. The process of claim 1 , wherein:

a molar ratio of the hydrogen peroxide to the titanium precursor is in a range from 2:1 to 50:1; and

a molar ratio of the alkali metal precursor or the zinc precursor to the titanium precursor is in a range 0.2:1 to 100:1.

10. The process of claim 9 , wherein the alkali metal precursor in the step (i) comprises sodium.

11. The process of claim 10 , wherein a weight ratio of the nitrogen-containing compound to titanium of the titanium precursor is in a range from 5:1 to 300:1.

12. The process of claim 11 , wherein the silica is a preformed silica.

13. The process of claim 11 , wherein the silica is a silica hydrogel.

14. The process of claim 1 , wherein

a weight ratio of titanium of the titanium precursor to the water (Ti:H 2 O) is in a range from 0.0001:1 to 0.02:1; and

a weight ratio of the silica to the water (silica:H 2 O) is in a range from 0.001:1 to 1:1.

15. The process of claim 14 , wherein the titanium precursor comprises a titanium carboxylate, a titanium halide, a titanium oxide, a titanium hydroxide, a titanium alkoxide, a titanium nitrate, a titanium sulfate, TiOSO 4 , or any combination thereof.

16. The process of claim 15 , wherein:

the silica is a preformed silica; and

the alkali metal precursor in the step (i) comprises sodium.

17. The process of claim 1 , wherein:

the reaction temperature is from 60° C. to 100° C.;

the silica is a preformed silica; and

the alkali metal precursor in the step (i) comprises sodium.

18. The process of claim 1 , wherein:

isolating the solid fraction comprises filtering and/or centrifuging; and

washing the solid fraction comprises contacting the solid fraction with a wash solution containing water.

19. The process of claim 1 , wherein the titanated silica support in the step (v) comprises:

the silica;

from 0.1 to 10 wt. % of titanium;

from 0.5 to 12 wt. % of water;

less than or equal to 4 wt. % of carbon; and

a bound alkali metal and/or a bound zinc;

wherein a molar ratio of the bound alkali metal to the titanium or the bound zinc to the titanium is from 0.02:1 to 3:1; and/or

wherein an amount of the bound alkali metal and/or the bound zinc is in a range from 0.01 to 2 mmol of the bound alkali metal or the bound zinc per gram of the silica.

20. The process of claim 1 , wherein:

the silica is a preformed silica;

the alkali metal precursor in the step (i) comprises sodium; and

the titanated silica support in the step (v) comprises:

the preformed silica;

from 0.1 to 10 wt. % of titanium;

from 0.5 to 12 wt. % of water;

less than or equal to 4 wt. % of carbon; and

bound sodium;

wherein a molar ratio of the bound sodium to the titanium is from 0.02:1 to 3:1; and/or

wherein an amount of the bound sodium is in a range from 0.01 to 2 mmol of the bound sodium per gram of the preformed silica.

21. The process of claim 20 , wherein:

the molar ratio of the bound sodium to the titanium is from 0.12:1 to 2.2:1; and/or

the amount of the bound sodium is in a range from 0.1 to 1.2 mmol of the bound sodium per gram of the preformed silica.

22. The process of claim 20 , wherein the molar ratio of the bound sodium to the titanium is from 0.2:1 to 1.8:1.

23. The process of claim 20 , wherein the amount of the bound sodium is in a range from 0.15 to 0.9 mmol of the bound sodium per gram of the silica.