Aluminum gradient aluminosilicate zeolite compositions

Patent metadata

Field	Value
Publication number	US-11021372-B2
Application number	US-201916372801-A
Country	US
Kind code	B2
Filing date	Apr 2, 2019
Priority date	Oct 3, 2016
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

Disclosed herein are compositions including aluminosilicate zeolite crystals with an 8 ring pore size having a depth dependent silica to alumina molar ratio and processes of making aluminosilicate zeolite crystals with an 8 ring pore size having a depth dependent silica to alumina molar ratio.

First claim

What is claimed is:

1. A composition comprising:
an aluminosilicate zeolite crystal with an 8 ring pore size, the aluminosilicate zeolite crystal having a surface silica to alumina molar ratio and an internal silica to alumina molar ratio, wherein the surface silica to alumina molar ratio is either higher or lower than the internal silica to alumina molar ratio.

2. The composition of claim 1 , wherein the aluminosilicate zeolite crystal comprises structural codes selected from the group consisting of AEI, AFX, CHA, LEV, AFT, EAB, KFI, SAT, TSC, SAV, ERI, and combinations thereof.

3. The composition of claim 1 , wherein the aluminosilicate zeolite crystal comprises CHA.

4. The composition of claim 1 , wherein the composition is about 80% or more crystalline on a molar basis.

5. The composition of claim 4 , wherein the composition is about 80% to about 95% crystalline on a molar basis.

6. The composition of claim 1 , wherein the composition has a zeolitic BET surface area of about 400 m 2 /g or more.

7. The composition of claim 1 , wherein the surface silica to alumina molar ratio is at least about 1.5 times higher or lower than the maximum value of the internal silica to alumina molar ratio.

8. The composition of claim 1 , wherein the internal silica to alumina molar ratio has a maximum value ranging from about 10 to about 250.

9. The composition of claim 1 , wherein the surface silica to alumina molar ratio ranges from about 5 to about 60.

10. The composition of claim 1 , wherein the composition has, on a molar basis, about 5% or more aluminum enrichment on a surface of the aluminosilicate zeolite crystal relative to the center of the aluminosilicate zeolite crystal.

11. The composition of claim 1 , having a Si2p to Al2p ratio intensity gradient as a function of etch depth based on normalized Al2p and Si2p intensities from XPS after argon sputtering, wherein the Si2p to Al2p ratio intensity at 20 nm to 50 nm etch depth is up to about 10, wherein the Si2p to Al2p ratio intensity at 250 nm to 450 nm etch depth ranges from about 10 to about 15, and wherein the Si2p to Al2p ratio intensity at 1000 nm etch depth ranges from about 11.5 to about 20.

12. A process comprising:
mixing a first amount of a first alumina source, a silica source, a mineralizing agent, and an organic structure directing agent to form a starting gel;
crystallizing the starting gel in a pressure vessel under hydrothermal conditions for a first duration; and
adding a second amount of a second alumina source to the pressure vessel over a second duration to form a final crystallization product;
wherein the final crystallization product comprises an aluminosilicate zeolite crystal with an 8 ring pore size, the aluminosilicate zeolite crystal having a surface silica to alumina molar ratio and an internal silica to alumina molar ratio, and wherein the surface silica to alumina molar ratio is either higher or lower than the internal silica to alumina molar ratio.

13. The process of claim 12 , wherein the first alumina source is the same as the second alumina source.

14. The process of claim 12 , wherein the first alumina source and second alumina source are independently selected from the group consisting of Al metal, water-soluble aluminum salts, and combinations thereof.

15. The process of claim 12 , wherein the second alumina source is NaAlO 2 or Al(C 3 H 7 O) 3 .

16. The process of claim 12 , wherein the silica source is selected from the group consisting of colloidal silica, fumed silica, tetraethyl orthosilicate (TEOS), sodium silicate, precipitated silica, and combinations thereof.

17. The process of claim 12 , wherein the mineralizing agent is selected from the group consisting of NaOH, KOH, F − , quaternary ammonium hydroxides, and combinations thereof.

18. The process of claim 12 , wherein the organic structure directing agent comprises quaternary ammonium cations with substituents selected from the group consisting of alkyl, adamantyl, cyclohexyl, aromatic, and combinations thereof.

19. The process of claim 12 , wherein aluminosilicate zeolite crystals resulting from the starting gel have a silica to alumina molar ratio ranging from about 5 to about 250.

20. The process of claim 12 , wherein aluminosilicate zeolite crystals resulting from the starting gel have a uniform distribution of a silica to alumina molar ratio.

21. The process of claim 12 , wherein the first duration defines a total crystallization time to obtain aluminosilicate zeolite crystals from the final crystallization product that are at least about 80% crystalline on a molar basis.

22. The process of claim 21 , wherein the total crystallization time ranges from about 1 hour to about 168 hours.

23. The process of claim 21 , wherein the adding step begins about ¼ to about ¾ into the first duration.

24. The process of claim 12 , wherein the second duration ranges from about 1 minute to about 168 hours.

25. The process of claim 12 , wherein the second duration ranges from about 1 minute to about 60 minutes.

26. The process of claim 12 , wherein the adding step comprises continuously adding the second amount of the second alumina source over the second duration,
wherein the second duration is equal to the first duration.

27. The process of claim 12 , further comprising filtering, drying, and calcining aluminosilicate zeolite crystals resulting from the final crystallization product.

28. The composition of claim 1 , wherein the surface silica to alumina molar ratio is at least about 5 times higher or lower than the maximum value of the internal silica to alumina molar ratio.

29. The composition of claim 1 , wherein the surface silica to alumina molar ratio is at least about 10 times higher or lower than the maximum value of the internal silica to alumina molar ratio.

30. The composition of claim 1 , wherein the surface silica to alumina molar ratio is at least about 30 times higher or lower than the maximum value of the internal silica to alumina molar ratio.

31. The composition of claim 1 , wherein the surface silica to alumina molar ratio is at least about 50 times higher or lower than the maximum value of the internal silica to alumina molar ratio.

32. The composition of claim 1 , wherein the internal silica to alumina molar ratio has a maximum value ranging from about 50 to about 250.

33. The composition of claim 1 , wherein the internal silica to alumina molar ratio has a maximum value ranging from about 90 to about 250.

34. The composition of claim 1 , wherein the internal silica to alumina molar ratio has a maximum value ranging from about 150 to about 250.

35. The composition of claim 1 , wherein the surface silica to alumina molar ratio ranges from about 10 to about 50.

36. The composition of claim 1 , wherein the surface silica to alumina molar ratio ranges from about 15 to about 40.

37. The composition of claim 1 , wherein the surface silica to alumina molar ratio ranges about 20 to about 40.

38. The composition of claim 1 , wherein the composition has, on a molar basis, about 10% or more aluminum enrichment on the surface of the aluminosilicate zeolite crystal relative to the center of the aluminosilicate zeolite cr

Assignees

• Basf Corp

Inventors

• Kunkes Eduard L
• Moini Ahmad
• Ortega Martitza I

Classifications

• C01B39/48 Primary

  using at least one organic template directing agent · CPC title

• C01B39/04

  using at least one organic template directing agent, e.g. an ionic quaternary ammonium compound or an aminated compound · CPC title

• B01J37/10

  in the presence of water, e.g. steam · CPC title

• B01J37/0018

  Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat) · CPC title

• B01J29/7015 Primary

  CHA-type, e.g. Chabazite, LZ-218 · CPC title