Method of preparing a molecular sieve composition

Abstract

A method of preparing a crystalline molecular sieve is provided, which method comprises (a) providing a reaction mixture comprising at least one source of ions of tetravalent element Y, at least one source of alkali metal hydroxide, water, optionally at least one seed crystal, and optionally at least one source of ions of trivalent element X, said reaction mixture having the following mole composition:

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which:

FIG. 1 presents a diagrammatic cross sectional view of a chamber for crystallizing a molecular sieve synthesis mixture under vapor phase conditions according to one embodiment of the invention, and

FIG. 2 presents a diagrammatic cross sectional view of a chamber for crystallizing a molecular sieve synthesis mixture under vapor phase conditions according to another embodiment of the invention.

Claims

1. A method of preparing a crystalline molecular sieve comprising: (a) providing a reaction mixture comprising at least one source of ions of tetravalent element Y, at least one source of alkali metal hydroxide, water, optionally at least one seed crystal, and optionally at least one source of ions of trivalent element X, said reaction mixture having the following mole composition: Y:X2=10 to infinityOH−:Y=0.001 to 2M+:Y=0.001 to 2

2. A method according to claim 1, characterized by the preformed extrudate comprising a structure directing agent R.

3. A method according to claim 1, characterized by the reactor containing water and/or structure directing agent R.

4. A method according to claim 3, characterized by the preformed extrudate being spaced from the water and/or structure directing agent in said reactor.

5. A method according to claim 1, characterized by the preformed extrudate being disposed in the reactor in a position that is spaced from at least one inner perimeter wall of said reactor.

6. A method according to claim 5, characterized by the reactor comprising a support for spacing the extruded mixture from the water and/or structure directing agent.

7. A method according to claim 1, characterized by the preformed extrudate being provided on a support in the reactor, the support being adapted to allow removal of the alkali metal hydroxide during crystallization of the preformed extrudate.

8. A method according to claim 1, characterized by the method comprising the additional steps of washing and drying the crystalline molecular sieve product.

9. A method according to claim 1, characterized by the mixture being dried prior to performing step b).

10. A method according to claim 1, characterized by the mixture being exposed to an autogenous pressure of 50 psig (345 kPa) to 500 psig (3450 kPa) and a temperature of 50° C. to 250° C. during crystallization.

11. A method according to claim 1, characterized by the Y:X2 ratio being 50 to 5000.

12. A method according to claim 1, characterized by the H2O:Y ratio being 0.5 to 5.

13. A method according to claim 1, the OH−:Y ratio being 0.1 to 1.

14. A method according to claim 1, characterized by the M+:Y ratio being 0.01 to 2.

15. A method according to claim 1, characterized by the mixture being suited to form crystals of molecular sieves of the MCM-22 family under the applied vapor phase crystallization conditions.

16. A method according to claim 15, characterized by the MCM-22 family molecular sieves comprising MCM-22, MCM-49, MCM-56.

17. A method according to claim 1, characterized by the pre-formed extrudate comprising a synthesized further molecular sieve to form a dual molecular sieve after crystallization.

18. A method according to claim 17, characterized by the synthesized further molecular sieve comprising zeolite beta, zeolite Y, Mordenite, ZSM-5 or ZSM-12.

19. A method according to claim 1, characterized by the pre-formed extrudate being free from a binder.

20. A method according to claim 1, characterized by the source of alkali metal hydroxide comprising a caustic agent such as sodium hydroxide solution.

21. A method according to claim 1, characterized by the tetravalent element comprising silicon.

22. A method according to claim 21 characterized by the source of ions of the tetravalent element comprising a source of silica.

23. A method according to claim 1, characterized by the trivalent element comprising aluminum.

24. A method according to claim 23 characterized by the source of ions of the trivalent element comprising a source of alumina.

25. A method according to claim 1 comprising water treating the crystallized extrudate and/or modifying the surface of the crystal to provide a metal oxide on the surface.

26. A catalyst or catalyst additive comprising a crystalline molecular sieve prepared by means of the method as defined in claim 1.

27. A process for converting hydrocarbons comprising the step of contacting a hydrocarbon feedstock under conversion conditions with crystalline molecular sieve made by the method of claim 1 or with a catalyst or catalyst additive according to claim 26.