Process for producing substantially binder-free zeolite

• US 5,460,796 A
• Filed: 11/07/1994
• Issued: 10/24/1995
• Est. Priority Date: 01/23/1991
• Status: Expired due to Term

• Current Assignee: Exxon Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: Exxon Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Verduijn, Johannes P.
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): Sample, David
• Application Number:
  US08/335,222
• Time in Patent Office: 351 Days
• Field of Search: 423/700, 423/709, 423/710, 423/712, 423/716, 423/DIG. 21, 423/DIG. 22, 423/DIG. 26, 423/DIG. 27, 423/DIG. 33, 423/DIG. 35, 423/DIG. 36 , 423/DIG. 38, 502/60, 502/64, 502/70, 502/71, 502/77
• US Class Current: 423/700
• CPC Class Codes: B01J 20/183 Physical conditioning without chemical treatment, e.g. drying, granulating, coating, irradiation
• CPC Class Codes: B01J 2229/42 Addition of matrix or binder particles
• CPC Class Codes: B01J 29/084 Y-type faujasite
• CPC Class Codes: B01J 29/40 of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
• CPC Class Codes: B01J 29/80 Mixtures of different zeolites
• CPC Class Codes: C01B 33/185 of crystalline silica-polymorphs having molecular sieve properties, e.g. silicalites
• CPC Class Codes: C01B 33/2838 of faujasite type, or type X or Y (UNION CARBIDE trade names; correspond to GRACE's types Z-14 and Z-14HS, respectively)
• CPC Class Codes: C01B 33/2876 from a reacting mixture containing an amine or an organic cation, e.g. a quaternary onium cation-ammonium, phosphonium, stibonium
• CPC Class Codes: C01B 39/02 Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
• CPC Class Codes: C01B 39/026 After-treatment
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/32 Spheres
• CPC Class Codes: C01P 2004/38 cube-like
• CPC Class Codes: C01P 2004/45 Aggregated particles or particles with an intergrown morphology
• CPC Class Codes: C01P 2004/50 Agglomerated particles
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2006/19 Oil-absorption capacity, e.g. DBP values
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: Y10S 423/21 Faujasite, e.g. X, Y, CZS-3, ECR-4, Z-14HS, VHP-R
• CPC Class Codes: Y10S 423/22 : MFI, e.g. ZSM-5. silicalite, LZ-241
• CPC Class Codes: Y10S 423/26 : Mazzite, e.g. ZSM-4, omega
• CPC Class Codes: Y10S 423/27 : Beta, e.g. NU-2
• CPC Class Codes: Y10S 423/33 : MTW, e.g. ZSM-12, NU-13, CZH-5, TPZ-3
• CPC Class Codes: Y10S 423/35 : TON, e.g. Theta-1, ISI-1, KZ-2, ZSM-22, NU-10
• CPC Class Codes: Y10S 423/36 : MTT, e.g. ZSM-23, ISI-1, KZ-1, EU-1, EU-4, EU-13
• CPC Class Codes: Y10S 423/38 : Offretite, e.g. TMA offreite

Abstract

Silica-bound extruded zeolites may be converted into binder-free zeolite aggregates by aging the zeolite in an aqueous ionic solution which contains hydroxy ions such that the initial molar ratio of OH-:SiO₂ is up to 1.2 and which causes the silica binder to be converted substantially to zeolite of the type initially bound. Such extrudates have excellent mechanical strength and show advantageous properties such as adsorption comparable with non-extruded zeolite powder.

Claims

1. A process for producing a zeolite containing less than 10 percent by weight silica binder, comprising aging at elevated temperature a silica-bound zeolite aggregate in an aqueous ionic solution which contains hydroxy ions such that the initial molar ratio of OH-:

SiO₂ is in the range of 0.1 up to 1.2 and which causes the silica binder to be converted to zeolite of the type initially bound or a type which is a crystallographic match for the zeolite initially bound, said silica-bound zeolite selected from the group consisting of MFI, KFI, Y, Beta, Omega, Chabasite, T, Offretite, ZSM-22, ZSM-23, titanosilicate, ZSM-34 and ZSM-12 type zeolites.

2. The process according to claim 1 wherein the OH-:

SiO₂ molar ratio is in the range of 0.3 to 0.6.

3. The process according to claim 1 wherein said aging is conducted at a temperature in the range of from 95°

C. to 200°

C.

4. The process according to claim 1, which further comprises aging a silica-bound aggregate of:

(a) a KFI-type zeolite which contains a strontium source in the presence of a solution containing a source of potassium aluminate;

or

(b) an MFI-type zeolite in the presence of a solution containing a positive tetrapropylammonium (TPA) species and a NA⁺ source.

5. The process according to claim 4 wherein the aging is carried out at 145°

to 155°

C.

6. The process according to claim 5, wherein the aging is carried out for 60 to 140 hours.

7. The process according to claim 4, wherein the KFI-type zeolite is a ZK-5 zeolite.

8. The process according to claim 7, wherein the ZK-5 zeolite is aged for 110 to 130 hours.

9. The process according to claim 4 wherein said zeolite is an MFI type zeolite.

10. The process according to claim 9, wherein the MFI-type zeolite is ZSM-5.

11. The process according to claim 9, wherein the MFI-type zeolite is a silicalite.

12. The process according to claim 1 wherein said zeolite is a Y type zeolite.

13. The process according to claim 12, which comprises aging a silica-bound aggregate of a Y-type zeolite in the presence of a solution containing sodium aluminate.

14. The process according to claim 13, wherein the aging is carried out at 95°

C. to 110°

C.

15. The process according to claim 14, wherein the aging is carried out for 18 to 28 hours.

16. The process according to claim 15, wherein the aged zeolite is washed and dried.

17. The process according to claim 1, wherein the aggregate particles have a hexane adsorption of at least 9 wt % at 30°

C. and p/po=0.25.

18. The process according to claim 1 wherein said silica contains no more than 2,000 ppm of alumina.

19. The process according to claim 1 wherein said binder-free zeolite contains less than 3% by weight of unconverted binder.

20. The process according to claim 1 wherein said silica binder is converted into zeolite crystals of sub-micron size.

21. A binder-free zeolite prepared by the process of claim 1.

22. A process for producing a zeolite containing less than 10 percent by weight silica binder, comprising aging at elevated temperature a silica-bound MFI type zeolite aggregate in an aqueous ionic solution containing hydroxy ions such that the initial molar ratio of OH-:

SiO₂ is up to 1.2 and which causes the silica binder to be converted to zeolite MFI or a crystallographic match for zeolite MFI.

23. The process according to claim 22 wherein said aqueous ionic solution contains a source of tetrapropylammonium ions.

24. The process according to claim 23 wherein said source of OH-ions is sodium hydroxide and wherein said solution is free of added alumina.

25. The process according to claim 22 wherein said aging is conducted at a temperature in the range of 130°

C. to 170°

C. for a period of from 60 to 140 hours.

26. The process according to claim 25 wherein said aging is conducted at a temperature in the range of 145°

C. to 155°

C. for a period of from 70 to 80 hours.

27. The process according to claim 23 wherein said aged zeolite is further washed and calcined.

28. The process according to claim 27 wherein said calcination is conducted at a temperature in the range of 450°

C. to 550°

C.

29. The process according to claim 22 wherein said MFI type zeolite is selected from the group consisting of silicalite and ZSM-5.

30. The process according to claim 29 wherein said MFI type zeolite is ZSM-5.

31. The process according to claim 22 wherein the OH-:

SiO₂ molar ratio is up to 0.6.

32. The process according to claim 31, wherein the MFI-type zeolite is aged for 70 to 80 hours.

33. The process according to claim 32, wherein the aged MFI-type zeolite is calcined after washing.

34. The process according to claim 33, wherein the calcination is carried out at 450°

to 550°

C.

35. The process according to claim 22 wherein said binder-free zeolite contains less than 3% by weight of unconverted binder.

36. A binder-free zeolite prepared by the process of claim 22.