Claims
- 1. A surface-inactivated catalyst composition comprising a medium or large pore shape-selective siliceous zeolite material having active internal Bronsted acid sites and containing a surface-inactivating amount of an organophosphorus base or cation, the base or cation having an effective cross section larger than the zeolite pore.
- 2. The catalyst composition of claim 1 wherein said zeolite material comprises aluminosilicate having a silica-to-alumina mole ratio of at least 12 and a constraint index of about 0.5 to 12 prior to phosphorus compound surface treatment.
- 3. The catalyst composition of claim 2 wherein the aluminosilicate consists essentially of HZSM-5 having an acid cracking value of about 50 to 400 prior to treatment, and wherein surface acidity is neutralized by a quaternary phosphonium compound.
- 4. The catalyst composition of claim 1 wherein the organophosphorus base comprises at least one phosphine or phosphonium compound.
- 5. The catalyst composition of claim 4 wherein the organophosphorus compound comprises a tetraphenyl phosphonium salt.
- 6. The catalyst of claims 1 and 2 wherein the zeolite material comprises ZSM-5 type zeolites or zeolite beta.
- 7. A method of making a shape-selective catalyst comprising
- contacting an acid medium pore zeolite having the structure of ZSM-5 with a solution of an organophosphorus deactivating agent to chemisorb said agent onto the zeolite surface for rendering said zeolite surface substantially inactive for acidic reaction, the deactivating agent comprising a tertiary phosphine or quaternary phosphonium compound having an effective cross-section greater than 5 Angstroms.
- 8. A surface-inactivated catalyst composition comprising a zeolite having the structure of ZSM-5 and having active internal Bronsted acid sites and containing no metals other than periodic group IIIB or IVB elements and having an acid cracking value of greater than 50 and containing a surface-inactivating amount of an organophosphorus base or cation, said base or cation having an effective cross-section larger than a zeolite pore.
- 9. The method of claim 7 wherein the zeolite catalyst having the structure of ZSM-5 has a constraint index less than 10 prior to treatment with the deactivating agent and a constraint index greater than 12 following treatment.
- 10. An improved medium pore siliceous zeolite material having internally active Bronsted acid sites and being surface inactivated by treatment with sufficient organophosphorus to increase substrate material constraint index by at least 20%, the organophosphorus having an effective cross-section larger than the zeolite pore.
- 11. The zeolite material of claim 10 wherein the pore size is about 5 to 8 Angstroms, wherein the untreated substrate has a constraint index less than 12, and the phosphorus-treated material has a constraint index of about 12 to 40.
- 12. The zeolite material of claim 11 wherein the substrate consists essentially of zeolite having the structure of ZSM-5 and containing no metals other than periodic group IIIB or IVB elements.
- 13. The zeolite material of claim 12 wherein the substrate consists essentially of aluminosilicate HZSM-5 having a constraint Index of about 6 to 10.
REFERENCE TO COPENDING APPLICATION
This is a continuation-in-part of application Ser. No. 808,973, filed Dec 16, 1985, now U.S. Pat. No. 4,658,079, which is a continuation-in-part of U.S. patent application Ser. No. 709,143, filed Mar 7, 1985, now U.S. Pat. No. 4,568,786, which is a continuation-in-part of U.S. patent application Ser. No. 598,139, filed Apr 9, 1964, now U.S. Pat. No. 4,520,221, incorporated herein by reference.
US Referenced Citations (4)
Continuation in Parts (3)
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Number |
Date |
Country |
Parent |
808973 |
Dec 1985 |
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Parent |
709143 |
Mar 1985 |
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Parent |
598139 |
Apr 1984 |
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