Claims
- 1. A method of producing a zeolite catalyst of improved stability wherein said zeolite catalyst comprises a zeolite having a silica/alumina ratio greater than 12 and a constraint index of 1 to 12, comprising steaming said zeolite catalyst in its fresh state under controlled conditions of temperature, time and steam partial pressure so as to initially increase the .alpha.-activity of said catalyst and produce a steamed catalyst having a peak .alpha.-activity, and subsequently reduce the .alpha.-activity from said peak .alpha.-activity to an .alpha.-activity substantially the same as the .alpha.-activity of said fresh catalyst and no more than 25% below the initial .alpha.-activity of said fresh catalyst, said steamed catalyst having enhanced stability over said fresh catalyst.
- 2. A method according to claim 1 wherein said zeolite is ZSM-5.
- 3. A method according to claim 1 wherein said catalyst further comprises metal promoters.
- 4. A method according to claim 3 wherein said catalyst has said metal promoters included on it prior to the steaming procedure.
- 5. A method according to claim 3 wherein said catalyst has said metal promoters included on it after the steaming procedure.
- 6. A method according to claim 1 wherein said silica/alumina ratio is no less than 20.
- 7. A method according to claim 6 wherein said silica/alumina ratio is about 40.
- 8. A method according to claim 6 wherein said silica/alumina ratio is about 70.
- 9. The product produced by the method of claim 1.
- 10. The product produced by the method of claim 2.
- 11. The product produced by the method of claim 3.
- 12. The product produced by the method of claim 4.
- 13. The product produced by the method of claim 5.
- 14. The product produced by the method of claim 6.
- 15. The product produced by the method of claim 7.
- 16. The product produced by the method of claim 8.
Parent Case Info
This application is a continuation of application Ser. No. 346,440, filed Feb. 8, 1982, now U.S. Pat. No. 4,429,176.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4247388 |
Banta et al. |
Jan 1981 |
|
4326994 |
Haag et al. |
Apr 1982 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
346440 |
Feb 1982 |
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