Extrusion-modified molecular sieve

• US 5,541,146 A
• Filed: 08/03/1994
• Issued: 07/30/1996
• Est. Priority Date: 02/25/1993
• Status: Expired due to Term

• Current Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Original Assignee: Mobil Oil Corporation (Exxon Mobil Corporation)
• Inventors: Chu, Cynthia T-W., Degnan, Thomas F., Chang, Clarence D., Shihabi, David S., Rodewald, Paul G.
• Primary Examiner(s): Lewis, Michael
• Assistant Examiner(s): Hendrickson, Stuart L.
• Application Number:
  US08/285,475
• Time in Patent Office: 727 Days
• Field of Search: 502/64, 502/263
• US Class Current: 502/64
• CPC Class Codes: B01J 2229/12 to alter the outside of the crystallites, e.g. selectivation
• CPC Class Codes: B01J 2229/32 Reaction with silicon compounds, e.g. TEOS, siliconfluoride
• CPC Class Codes: B01J 2229/42 Addition of matrix or binder particles
• CPC Class Codes: B01J 29/06 Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
• 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 31/0274 containing silicon ligands in coordination complexes B01J31/1608
• CPC Class Codes: B01J 31/124 Silicones or siloxanes or comprising such units
• CPC Class Codes: C07C 15/08 Xylenes
• CPC Class Codes: C07C 6/123 of only one hydrocarbon
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts

Abstract

A catalytic molecular sieve which has been preselectivated by agglomerating with an organosilicon compound. The invention also includes a method for agglomeration-preselectivation and the shape selective catalyst which results from the agglomeration preselectivation.

Claims

1. A method for agglomeration pre-selectivating a catalytic molecular sieve comprising a) forming a mixture comprising crystalline molecular sieve material having a Constraint Index of 1 to 12 and an organosilicon compound in the presence of water at a molecular sieve/organosilicon compound weight ratio of from about 1/10 to about 100/1, said organosilicon compound substantially incapable of entering the crystalline molecular sieve pores and said organosilicon compound comprising an aqueous form, and b) agglomerating the mixture.

2. The method of claim 1 wherein the mixture comprising crystalline molecular sieve material and organosilicon compound further comprises a matrix material.

3. The method of claim 2 wherein the matrix material comprises amorphous silica.

4. The method of claim 1 wherein the organosilicon compound is selected from the group consisting of silicones, organosilanes siloxanes and polysiloxanes.

5. The method of claim 1 wherein the aqueous form is selected from the group consisting of solutions, aerosols, and emulsions.

6. The method of claim 5 wherein the emulsion includes a surfactant which is a polyoxyethylene-octylphenol ether.

7. The method of claim 1 wherein the organosilicon compound is a polysiloxane.

8. The method of claim 7 wherein the polysiloxane is phenylmethylpolysiloxane.

9. The method of claim 1 further comprising c) subsequent to a) and b), contacting the catalytic molecular sieve with a mixture comprising toluene feedstock and a second silicon source, said contact occurring for at least one hour at reaction conditions for converting toluene to xylene.

10. The method of claim 9 wherein the second silicon source is a silicone.

11. The method of claim 10 wherein the silicone comprises a mixture of phenylmethylsilicone and dimethylsilicone.

12. An agglomerated catalyst comprising:

A molecular sieve having a Constraint Index of about 1-12 which has been agglomeration pre-selectivated by agglomerating a mixture comprising crystalline molecular sieve material and organosilicon compound in the presence of water, said compound comprising an aqueous form, said agglomeration pre-selectivated molecular sieve having para-selectivity in toluene disproportionation to produce at least 90% para-xylene product relative to all C₈ products, with at least 15% toluene conversion.

13. The catalyst of claim 12 wherein after being agglomeration pre-selectivated, the molecular sieve is ion exchanged to contain ions selected from the group consisting of hydrogen, hydrogen precursor, metals of Periodic Table Group VIII and mixtures thereof.

14. The catalyst of claim 12 wherein the mixture comprising crystalline molecular sieve material and organosilicon compound further comprises a matrix material.

15. The catalyst of claim 14 wherein the matrix material comprises amorphous silica.

16. The catalyst of claim 12 wherein the organosilicon compound is selected from the group consisting of silicones, organosilanes, siloxanes and polysiloxanes.

17. The catalyst of claim 12 wherein the aqueous form is selected from the group consisting of solutions, aerosols, and emulsions.

18. The catalyst of claim 17 wherein the emulsion includes a surfactant which is a polyoxyethylene-octylphenol ether.

19. The catalyst of claim 12 wherein the organosilicon compound is a polysiloxane.

20. The catalyst of claim 19 wherein the polysiloxane is phenylmethylpolysiloxane.

21. The catalyst of claim 12 wherein the catalyst which has been first agglomeration pre-selectivated is subsequently treated by contacting with a mixture comprising toluene feedstock and a second silicon source, said contact occurring for at least one hour at reaction conditions for converting toluene to xylene.