US4218573A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Xylene isomerization
Assignee: Mobil Oil AS
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Filing: 1979-06-01
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Granted: 1980-08-19
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Expires: 1999-06-01
Abstract
Abstract Isomerization of xylenes in admixture with ethyl benzene by contact with a zeolite catalyst such as ZSM-5 is improved by use of zeolite having a substantial alkali metal content at a temperature above about 800 DEG F. At these conditions, conversion of ethylbenzene follows a different reaction path which permits high conversion of ethylbenzene to benzene without loss of xylenes by disproportionation.
Inventors
- 👤 Samuel A. Tabak
- 👤 Roger A. Morrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:20
CPC Classifications
C; C07; C07C; C07C15/00; C07C15/02; C07C15/067; C07C15/08; B; B01; B01J; B01J29/00; B01J29/04; B01J29/06; B01J29/40; B01J29/42; B01J29/44; C07C4/00; C07C4/08; C07C4/12; C07C4/14; C07C4/18; C07C5/00; C07C5/22; C07C5/27; C07C5/2729; C07C5/2732; C07C5/2737; B01J2229/00; B01J2229/10; B01J2229/26; B01J2229/30; B01J2229/42; C07C2529/00; C07C2529/04; C07C2529/06; C07C2529/40; C07C2529/42; C10; C10G; C10G2400/00; C10G2400/30; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/52
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
137 words
In a process for isomerizing the xylene content of a charge mixture of eight carbon atom aromatic hydrocarbon compounds which mixture contains xylene and ethylbenzene by contact at conversion conditions with a catalyst comprising a zeolite having a silica/alumina ratio greater than 12 and a constraint index of 1 to 12, the improvement resulting in conversion of ethylbenzene to benzene which comprises using as said catalyst a zeolite containing a substantial proportion of alkali metal sufficient to substantially reduce activity of said zeolite for catalysis of disproportionation reactions and maintaining a conversion temperature of about 800° F. to about 1000° F., said reduced activity being such that less than 2 weight per cent of xylene is lost by contacting xylene with said reduced activity catalyst at 900° F., 200 psig and liquid hourly space velocity of 5.
Claim 2
Dependent Claim
137 words
In a process for isomerizing the xylene content of a charge mixture of eight carbon atom aromatic hydrocarbon compounds which mixture contains xylene and ethylbenzene by contact at conversion conditions with a catalyst comprising a zeolite having a silica/alumina ratio greater than 12 and a constraint index of 1 to 12, the improvement resulting in conversion of ethylbenzene to benzene which comprises using as said catalyst a zeolite containing a substantial proportion of alkali metal sufficient to substantially reduce activity of said zeolite for catalysis of disproportionation reactions and maintaining a conversion temperature of about 800° F. to about 1000° F., said reduced activity being such that less than 2 weight per cent of xylene is lost by contacting xylene with said reduced activity catalyst at 900° F., 200 psig and liquid hourly space velocity of 5.
Claim 3
Dependent Claim
11 words
A process according to claim 1 wherein said zeolite is ZSM-5.
Claim 4
Dependent Claim
12 words
A process according to claim 1 wherein said zeolite is sodium ZSM-5.
Claim 5
Dependent Claim
20 words
A process according to claim 1 wherein said catalyst also comprises a metal of Group VIII of the Periodic Table.
Claim 6
Dependent Claim
11 words
A process according to claim 4 wherein said zeolite is ZSM-5.
Claim 7
Dependent Claim
12 words
A process according to claim 4 wherein said zeolite is sodium ZSM-5.
Claim 8
Dependent Claim
14 words
A process according to claim 4 wherein said charge mixture is admixed with hydrogen.
Claim 9
Dependent Claim
11 words
A process according to claim 7 wherein said zeolite is ZSM-5.
Claim 10
Dependent Claim
12 words
A process according to claim 7 wherein said zeolite is sodium ZSM-5.
Claim 11
Dependent Claim
15 words
A process according to claim 1 wherein the reaction is conducted at substantially atmospheric pressure.
Claim 12
Dependent Claim
28 words
A process according to claim 1 resulting in conversion of ethyl benzene to benzene at substantially no loss of xylene in the product as compared to the charge.
Claim 13
Dependent Claim
14 words
A process according to claim 1 wherein the said charge mixture contains paraffin hydrocarbons.
Claim 14
Dependent Claim
16 words
A process according to claim 1 wherein the said charge mixture consists essentially of aromatic hydrocarbons.
References Cited (Backward Citations)
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |