Amorphous silica-alumina composition and a method of making and using such composition
View Patent ↗Described is a novel amorphous silica-alumina composition having a high ratio of pore volume contained in large pores to pore volume contained in medium to small pores. The amorphous silica-alumina composition also may have the characteristic of a strong aluminum-NMR penta-coordinated peak representing greater than 30% of the total aluminum and a method of making such novel amorphous silica-alumina composition using a pH swing preparation method.
1. A silica-alumina powder composition, comprising:
amorphous silica-alumina having an A/B ratio exceeding 2.2, wherein A in said ratio is the pore volume contained in pores of said composition having a pore diameter less than 2150 Å and B in said ratio is the pore volume contained in pores of said composition having a pore diameter of less than 210 Å.
2. A silica-alumina composition as recited in claim 1 , wherein said amorphous silica-alumina has a silica content in the range of from 10 to 90 weight percent and an alumina content in the range of from 10 to 90 weight percent.
3. A silica-alumina composition as recited in claim 2 , wherein said amorphous silica-alumina contains less than 10 weight percent alumina of the total weight of the silica-alumina composition that is in the crystalline phase.
4. A silica-alumina composition as recited in claim 3 , wherein said amorphous silica-alumina has a surface area in the range of from 190 m 2 /gm to 400 m 2 /gm.
5. A silica-alumina composition as recited in claim 4 , wherein said amorphous silica-alumina has a pore volume in the range of from 0.8 cc/gm to 1.3 cc/gm.
6. A silica-alumina powder composition as recited in claim 5 , wherein amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 30% of the aluminum of said amorphous silica-alumina.
7. A silica-alumina composition as recited in claim 1 , wherein said A/B ratio exceeds 2.4.
8. A silica-alumina composition as recited in claim 7 , wherein said amorphous silica-alumina has a silica content in the range of from 25 to 75 weight percent and an alumina content in the range of from 25 to 75 weight percent; wherein said amorphous silica-alumina has a surface area in the range of from 200 m 2 /gm to 350 m 2 /gm; wherein said amorphous silica-alumina has a pore volume in the range of from 0.9 cc/gm to 1.2 cc/gm; and wherein said amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 30% of the aluminum of said amorphous silica-alumina.
9. A silica-alumina composition as recited in claim 1 , wherein said A/B ratio exceeds 2.5.
10. A silica-alumina composition as recited in claim 9 , wherein said amorphous silica-alumina has a silica content in the range of from 25 to 75 weight percent and an alumina content in the range of from 25 to 75 1 weight percent; wherein said amorphous silica-alumina has a surface area in the range of from 200 m 2 /gm to 350 m 2 /gm; wherein said amorphous silica-alumina has a pore volume in the range of from 0.9 cc/gm to 1.2 cc/gm; and wherein said amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 30% of the aluminum of said amorphous silica-alumina.
11. A silica-alumina composition as recited in claim 10 , wherein said amorphous silica-alumina has a silica content in the range of from 25 to 75 weight percent and an alumina content in the range of from 25 to 75 weight percent; wherein said amorphous silica-alumina has a surface area in the range of from 200 m 2 /gm to 350 m 2 /gm; wherein said amorphous silica-alumina has a pore volume in the range of from 0.9 cc/gm to 1.2 cc/gm.
12. A silica-alumina composition as recited in claim 11 , wherein said amorphous silica-alumina has a silica content in the range of from 25 to 75 weight percent and an alumina content in the range of from 25 to 75 weight percent; wherein said amorphous silica-alumina has a surface area in the range of from 200 m 2 /gm to 350 m 2 /gm; wherein said amorphous silica-alumina has a total pore volume in the range of from 0.9 cc/gm to 1.2 cc/gm; and wherein said amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 40% of the aluminum of said amorphous silica-alumina.
13. A silica-alumina powder composition as recited in claim 1 , wherein amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 35% of the aluminum of said amorphous silica-alumina.
14. A silica-alumina composition as recited in claim 13 , wherein said amorphous silica-alumina has a silica content in the range of from 25 to 75 weight percent and an alumina content in the range of from 25 to 75 weight percent; wherein said amorphous silica-alumina has a surface area in the range of from 200 m 2 /gm to 350 m 2 /gm; wherein said amorphous silica-alumina has a pore volume in the range of from 0.9 cc/gm to 1.2 cc/gm.
15. A silica-alumina composition as recited in claim 14 , wherein said amorphous silica-alumina has a silica content in the range of from 25 to 75 weight percent and an alumina content in the range of from 25 to 75 weight percent; wherein said amorphous silica-alumina has a surface area in the range of from 200 m 2 /gm to 350 m 2 /gm; wherein said amorphous silica-alumina has a pore volume in the range of from 0.9 cc/gm to 1.2 cc/gm; and wherein said amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 30% of the aluminum of said amorphous silica-alumina.
16. A silica-alumina powder composition as recited in claim 1 , wherein amorphous silica-alumina exhibits the characteristic of a strong aluminum-NMR penta-coordination peak representing greater than 40% of the aluminum of said amorphous silica-alumina.
17. A silica-alumina composition as recited in claim 1 , wherein said amorphous silica-alumina contains less than 8 weight percent alumina of the total weight of the silica-alumina composition that is in the crystalline phase.
18. A silica-alumina composition as recited in claim 1 , wherein said amorphous silica-alumina contains less than 5 weight percent alumina of the total weight of the silica-alumina composition that is in the crystalline phase.