Microporous crystalline material comprising a molecular sieve or zeolite having an 8-ring pore opening structure and methods of making and using same
View Patent ↗There is disclosed a hydrothermally stable microporous crystalline material comprising a molecular sieve or zeolite having an 8-ring pore opening structure, such as SAPO-34 or aluminosilicate zeolite, able to retain a specific percentage of its surface area and micropore volume after treatment with heat and moisture, such as at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900° C. in the presence of up to 10 volume percent water vapor for a time ranging from 1 to 16 hours. Methods of using the disclosed crystalline material, such as in the SCR of NO x in exhaust gas are also disclosed, as are methods of making such materials.
1. A hydrothermally stable microporous crystalline material comprising SAPO-34 having a crystal size greater than 0.3 microns, which after exposure to temperatures ranging from 700 to 900° C. in the presence of up to 10 volume percent water vapor for a time of 16 hours, retains at least 80% of its surface area and micropore volume and an acidity of at least 0.35 mmol/g.
2. A microporous crystalline material of claim 1 , wherein said crystalline material comprises iron and/or copper.
3. A microporous crystalline material of claim 2 , wherein said iron and/or copper are introduced into said solid by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.
4. A microporous crystalline material of claim 1 , wherein said SAPO-34 contains SiO 2 in an amount ranging from 1-20%.
5. A microporous crystalline material of claim 1 , wherein said SAPO-34 has a crystal size ranging from 0.3 to 5.0 microns.
6. A microporous crystalline material of claim 1 , having an initial surface area of at least 650 m 2 /g.
7. A microporous crystalline material of claim 1 , having an initial micropore volume of at least 0.25 cc/g.
8. A hydrothermally stable microporous crystalline material for SCR of NO x with urea or ammonia, wherein said crystalline material comprises iron and/or copper containing SAPO-34 having a crystal size greater than 0.3 microns which retains at least 80% of its surface area and micropore volume after exposure to temperatures of up to 900 ° C. in the presence of up to 10 volume percent water vapor for up to 1 hour.
9. A microporous crystalline material of claim 8 , wherein the iron and/or copper are introduced into said material by liquid-phase or solid ion-exchange or incorporated by direct-synthesis.
10. A microporous crystalline material of claim 8 , wherein said iron comprises at least 0.20 weight percent of the total weight of said material.
11. A microporous crystalline material of claim 8 , wherein said copper comprises at least 1.0 weight percent of the total weight of said material.
12. A microporous crystalline material of claim 8 , wherein said SAPO-34 contains 1-20% of SiO 2 .
13. A method for making silicoaluminophosphate molecular sieve comprising SAPO-34, said method comprising:
mixing sources of alumina, silica, and phosphate with a TEAOH solution and water to form a gel;
heating said gel in an autoclave at a temperature ranging from 150 to 180° C. to form a product;
cooling and optionally washing said product in water;
calcining said product to form a molecular sieve comprising SAPO-34 having a crystal size greater than 0.3 microns and containing from 1-20% SiO 2 , wherein said molecular sieve after exposure to temperatures ranging from 700 to 900° C. in the presence of up to 10 volume percent water vapor for 16 hours, retains at least 80% of its surface area and micropore volume and has an acidity of at least 0.35 mmol/g.
14. The method of claim 13 , wherein said source of alumina is pseudoboehmite alumina.
15. The method of claim 13 , wherein said source of silica is a silica sol.
16. The method of claim 13 , wherein said source of phosphate is phosphoric acid.
17. The method of claim 13 , further comprising a cation exchange step.
18. The method of claim 17 , wherein said cation is chosen from iron and copper.
19. The method of claim 13 , wherein said gel is heated in an autoclave at a temperature of 180° C.
20. A microporous crystalline material of claim 1 , wherein said exposure comprises a temperature of 900° C.
21. A microporous crystalline material of claim 1 , wherein said crystalline material has an acidity value of at least 0.4 mmol/g after exposure.
22. A microporous crystalline material of claim 21 , wherein said crystalline material has an acidity value ranging from 0.4 to 1.00 mmol/g after exposure.
23. A microporous crystalline material of claim 1 , wherein said SAPO-34 has a crystal size ranging from 0.3 to 5.0 microns.
24. A hydrothermally stable microporous crystalline material comprising SAPO-34, having a crystal size greater than 0.3 microns and an acidity of at least 0.35 mmol/g and retains at least 80% of its surface area and micropore volume after hydrothermal aging comprising exposure to temperatures ranging from 700 to 900° C. in the presence of up to 10 volume percent water vapor for a time of 1 to 16 hours.
25. A microporous crystalline material of claim 24 , wherein said SAPO-34 contains SiO 2 in an amount ranging from 1-20%.
26. A microporous crystalline material of claim 24 , having an initial surface area of at least 650 m 2 /g.
27. A microporous crystalline material of claim 24 , having an initial micropore volume of at least 0.25 cc/g.
28. A hydrothermally stable microporous crystalline material of claim 8 , wherein said SAPO-34 has a crystal size ranging from 0.3 to 5.0 microns.
29. A microporous crystalline material of claim 2 , wherein said copper comprises about 2.0 weight percent of the total weight of said material.
30. A microporous crystalline material of claim 8 , wherein said copper comprises about 2.0 weight percent of the total weight of said material.