Claims
- 1. A process for the selective production of para-xylene which comprises reacting toluene with methanol under alkylation conditions in the presence of a catalyst comprising a porous crystalline material having a Diffusion Parameter for 2,2 dimethylbutane of about 0.1-15 sec−1 when measured at a temperature of 120° C. and a 2,2 dimethylbutane pressure of 60 torr (8 kPa) wherein said porous crystalline material has undergone prior treatment with steam at a temperature of at least 950° C. to adjust the Diffusion Parameter of said material to about 0.1-15 sec−1.
- 2. The process of claim 1, wherein said Diffusion Parameter of said porous crystalline material is about 0.5-10 sec−1.
- 3. The process of claim 1, wherein said porous crystalline material has undergone prior treatment with steam at a temperature of at least 1000° C. for between about 10 minutes and about 100 hours.
- 4. The process of claim 3, wherein the steaming reduces the pore volume of the catalyst to not less than 50% of that of the unsteamed catalyst.
- 5. The process of claim 1, wherein the catalyst contains at least one oxide modifier selected from the group consisting of oxides of elements of Groups IIA, IIIA, IIIB, IVA, IVB, VA and VIA of the Periodic Table.
- 6. The process of claim 1, wherein the catalyst contains at least one oxide modifier selected from the group consisting of oxides of boron, magnesium, calcium, lanthanum and phosphorus.
- 7. The process of claim 6, wherein the catalyst contains about 0.05 to about 20 wt % of the oxide modifier based on the elemental modifier.
- 8. The process of claim 7, wherein the catalyst contains about 0.1 to about 10 wt % of the oxide modifier based on the elemental modifier.
- 9. The process of claim 1, wherein the catalyst has an average particle size of about 20 to 200 microns.
- 10. The process of claim 1, wherein the porous crystalline material is an aluminosilicate zeolite.
- 11. The process of claim 10, wherein said zeolite is ZSM-5 or ZSM-11.
- 12. The process of claim 1, wherein said alkylation conditions include a temperature between about 500 and 700° C., a pressure of between about 1 atmosphere and 1000 psig (100 and 7000 kPa), a weight hourly space velocity between about 0.5 and about 1000 and a molar ratio of toluene to methanol of at least about 0.2.
- 13. The process of claim 1, wherein said alkylation is conducted in the presence of added hydrogen and/or water such that the molar ratio of hydrogen and/or water to toluene+methanol in the feed is about 0.01 to about 10.
Parent Case Info
This application is a DIV of U.S. Ser. No. 09/341,008 filed Nov. 15, 1999 now U.S. Pat. No. 6,423,897, which is a 371 of PCT/US97/18079 filed Oct. 2, 1997.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4380685 |
Chu |
Apr 1983 |
A |
4491678 |
Oda et al. |
Jan 1985 |
A |