US4599475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for xylene isomerization using ZSM-23 zeolite
Assignee: Mobil Oil AS
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Filing: 1985-06-19
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Granted: 1986-07-08
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Expires: 2005-06-19
Abstract
Abstract An improved process is disclosed for the isomerization of xylenes over a zeolite which may contain a platinum group metal. The improvement resides in the use of ZSM-23 zeolite which exhibits enhanced selectivity which inhibits the production of undesired C9+ aromatic transalkylation by-products. ZSM-23 having pores substantially unobstructed by silica, such as that made from a forming mixture containing amorphous precipitated silica as a silica source, has been found to be particularly useful in the process of the present invention.
Inventors
- 👤 Charles T. Kresge
- 👤 James C. Vartuli
- 👤 Michael P. Nicoletti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:37
CPC Classifications
C; C07; C07C; C07C5/00; C07C5/22; C07C5/27; C07C5/2702; C07C5/2708; B; B01; B01J; B01J29/00; B01J29/04; B01J29/06; B01J29/70; B01J29/72; B01J29/74; C07C5/2724; B01J2229/00; B01J2229/10; B01J2229/20; B01J2229/26; B01J2229/30; B01J2229/42; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/52
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
72 words
A process for isomerizing an isomerization feed containing an aromatic C 8 mixture of ethylbenzene and xylene by which ethylbenzene and m-xylene conversion is enhanced, said process comprising contacting said feed under conversion conditions with a catalyst comprising ZSM-23 zeolite having a silica to alumina ratio of at least about 12, which zeolite is capable of sorbing greater than about 3 weight percent cyclohexane and greater than about 6.1 weight percent n-hexane.
Claim 2
Dependent Claim
72 words
A process for isomerizing an isomerization feed containing an aromatic C 8 mixture of ethylbenzene and xylene by which ethylbenzene and m-xylene conversion is enhanced, said process comprising contacting said feed under conversion conditions with a catalyst comprising ZSM-23 zeolite having a silica to alumina ratio of at least about 12, which zeolite is capable of sorbing greater than about 3 weight percent cyclohexane and greater than about 6.1 weight percent n-hexane.
Claim 3
Dependent Claim
85 words
A process for isomerizing an isomerization feed containing an aromatic C 8 mixture of ethylbenzene and xylene by which ethylbenzene and m-xylene conversion is enhanced, said process comprising contacting said feed, under conversion conditions with a catalyst comprising ZSM-23 zeolite having a silica to alumina ratio of at least about 12, capable of sorbing greater than about 3 weight percent cyclohexane and greater than about 6.1 weight percent n-hexane, which zeolite is prepared from a forming mixture containing amorphous precipitated silica as a silica source.
Claim 4
Dependent Claim
85 words
A process for isomerizing an isomerization feed containing an aromatic C 8 mixture of ethylbenzene and xylene by which ethylbenzene and m-xylene conversion is enhanced, said process comprising contacting said feed, under conversion conditions with a catalyst comprising ZSM-23 zeolite having a silica to alumina ratio of at least about 12, capable of sorbing greater than about 3 weight percent cyclohexane and greater than about 6.1 weight percent n-hexane, which zeolite is prepared from a forming mixture containing amorphous precipitated silica as a silica source.
Claim 5
Dependent Claim
13 words
The process of claim 2 wherein said zeolite contains a Group VIII metal.
Claim 6
Dependent Claim
12 words
The process of claim 3 wherein said Group VIII metal is platinum.
Claim 7
Dependent Claim
24 words
The process of claim 2 wherein said zeolite is capable of sorbing greater than about 3.5 weight percent cyclohexane and 6.5 weight percent n-hexane.
Claim 8
Dependent Claim
43 words
The process of claim 2 wherein said conversion conditions include a temperature of from about 260° C. to about 538° C., a pressure of about 0 to about 1500 psig and a weight hourly space velocity of between about 0.5 and about 100.
Claim 9
Dependent Claim
17 words
The process of claim 2 wherein said aromatic C 8 mixture contains ethylbenzene, para-xylene, meta-xylene, and ortho-xylene.
Claim 10
Dependent Claim
15 words
The process of claim 2 wherein said zeolite is ZSM-23 predominately in the hydrogen form.
Claim 11
Dependent Claim
36 words
The process of claim 1 wherein said zeolite can sorb n-hexane and cyclohexane at a sorption ratio greater than about 1.5 weight percent n-hexane sorbed/weight percent cyclohexane sorbed at 40 mm partial pressure and room temperature.
Claim 12
Dependent Claim
14 words
The process of claim 9 wherein said sorption ratio is greater than about 2.
Claim 13
Dependent Claim
16 words
The process of claim 9 wherein said sorption ratio ranges between about 2 and about 4.
Claim 14
Dependent Claim
36 words
The process of claim 2 wherein said zeolite can sorb n-hexane and cyclohexane in a sorption ratio greater than about 1.5 weight percent n-hexane sorbed/weight percent cyclohexane sorbed at 40 mm partial pressure and room temperature.
Claim 15
Dependent Claim
14 words
The process of claim 12 wherein said sorption ratio is greater than about 2.
Claim 16
Dependent Claim
16 words
The process of claim 12 wherein said sorption ratio ranges between about 2 and about 4.
References Cited (Backward Citations)
US3130007A
Cited
US4151189A
Cited
US4076842A
Cited
GB1567948A
Cited
US4181811A
Cited
US4255600A
Cited
US4309281A
Cited
US4326994A
Cited
US4385195A
Cited
US4372930A
Cited
EP0042225A1
Cited
US4397825A
Cited
US4547605A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-07 | 1990-01-06 | 1990-07-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-07 | 1994-01-06 | 1994-07-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-07 | 1998-01-06 | 1998-07-08 | $7700.00 | Window Closed / Lapsed |