Claims
- 1. In a process for the isomerization of a xylene feed stock to produce a product having an enhanced para-xylene content, the steps comprising:
- a. passing said xylene feed stock containing meta-xylene into a reaction zone and in contact with a mordenite catalyst having a silica/alumina mole ratio of at least 30,
- b. supplying hydrogen to said reaction zone,
- c. operating said reaction zone at a temperature within the range of 350.degree.-600.degree. C. and a hydrogen pressure within the range of 200-1000 psig to effect isomerization of said xylene feedstock to provide a product of increased para-xylene content reduced meta-xylene content, and
- d. withdrawing said product from said reaction zone.
- 2. The method of claim 1 wherein said mordenite catalyst has a silica/alumina mole ratio within the range of 40-60.
- 3. The method of claim 1 wherein said mordenite catalyst has a silica/alumina ratio of about 48.
- 4. The method of claim 1 wherein said feedstock contains a mixture of xylene isomers.
- 5. In a process for the isomerization of a xylene feed stock to produce a product having an enhanced para-xylene content and a diminished ethylbenzene content, the steps comprising:
- a. passing said xylene feed stock containing a mixture of xylene isomers and ethylbenzene in which para-xylene is present in less than an equilibrium amount and ethylbenzene is present in a concentration greater than the para-xylene concentration into a reaction zone and in contact with a mordenite catalyst having a silica/alumina mole ratio of at least 30,
- b. supplying hydrogen to said reaction zone,
- c. operating said reaction zone at a temperature within the range of 350.degree.-600.degree. C. and a hydrogen pressure within the range of 200-1000 psig to effect isomerization of xylene isomers to provide an increased para-xylene content and disproportionation of ethylbenzene to provide a reduced ethylbenzene content, and
- d. withdrawing a product of increased para-xylene content and a diminished ethylbenzene content from said reaction zone.
- 6. The method of claim 5 wherein said mordenite catalyst has a silica/alumina mole ratio within the range of 40-60.
- 7. The method of claim 5 wherein said mordenite catalyst has a silica/alumina ratio of about 48.
- 8. The method of claim 5 wherein said feed stream contains ortho-xylene in an amount greater than the para-xylene content of said feed stream and wherein the isomerization product withdrawn from said reaction zone contains a lower ortho-xylene content than said feed stream.
- 9. The method of claim 5 wherein said reaction zone is operated at a temperature within the range of 350.degree.-500.degree. C.
- 10. The method of claim 9 wherein said reaction zone is operated at a hydrogen pressure within the range of 200-600 psig.
- 11. The method of claim 5 wherein said reaction zone is operated at a hydrogen pressure of at least 300 psig.
- 12. The method of claim 11 wherein said reaction zone is operated at a temperature within the range of 400.degree.-440.degree. C.
- 13. The method of claim 5 wherein hydrogen is supplied to said reaction zone at a rate to provide a mole ratio of hydrogen to the composite of xylene and ethylbenzene in said feed stream of at least 3.
- 14. The method of claim 5 wherein said xylene feedstock is supplied to said reaction zone to provide a space velocity over said catalyst within the range of 1-10 WHSV.
- 15. The method of claim 14 wherein said space velocity is within the range of 3-7 WHSV.
- 16. The method of claim 5 further comprising the step of prior to supplying said xylene feedstock to said reaction zone, initiating a start-up procedure by supplying a hot preflush gas to said reaction zone and flowing said hot gas into contact with said mordenite catalyst.
- 17. The method of claim 16 wherein said preflush gas is supplied to said reaction zone at a temperature of at least 350.degree. C. for a period of at least 24 hours.
- 18. The method of claim 16 wherein said preflush gas comprises hydrogen.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 826,848 filed Feb. 6, 1986, now U.S. Pat. No. 4,665,258, entitled "Toluene Disproportionation Process."
US Referenced Citations (9)
Non-Patent Literature Citations (2)
Entry |
"Xylenes and Ethylbenzene," Kirk-Othmer, Encyclopedia of Chemical Technology, Third Edition, John Wiley & Sons, 1984, vol. 24, pp. 709-744. |
"Molecular Sieves," Kirk-Othmer, Encyclopedia of Chemical Technology, Third Edition, John Wiley & Sons, 1984, vol. 15, pp. 638-643. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
826848 |
Feb 1986 |
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