Patent US1834829A successfully refreshed from Google Patents.
EP0095846A2
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EP
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Preparation of modified zeolites
Assignee: Imperial Chemical Industries Ltd
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Filing: 1983-05-13
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Granted: —
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Expires: 2003-05-13
Abstract
Abstract Selective and controlled dealumination of an aluminosilicate zeolite is achieved by filling the pore system of the zeolite with a foreign material, for example coke, removing part of the foreign material from the outer portion of the zeolite, for example by heating in a gas stream comprising oxygen, dealuminating the outer portion, and then removing the remainder of the foreign material. Use of such a partially dealuminated zeolite as catalyst in a toluene disproportionation reaction leads to greater selectivity to para- xylene.
Inventors
- 👤 John Dewing
- 👤 Philip John Hogan
- 👤 Allan Stewart
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 12:21
CPC Classifications
C; C07; C07C; C07C6/00; C07C6/08; C07C6/12; C07C6/123; C01; C01B; C01B39/00; C01B39/02; C01B39/026; B; B01; B01J; B01J2229/00; B01J2229/10; B01J2229/16; C07C2529/00; C07C2529/04; C07C2529/06; Y; Y10; Y10S; Y10S423/00; Y10S423/22
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
121 words
A process for the controlled removal of aluminium from a crystalline aluminosilicate zeolite which comprises: (a) subjecting the zeolite to a treatment whereby the pore system of the zeolite is filled substantially completely with a foreign material; (b) selectively removing a portion of said foreign material from an outer zone of the zeolite crystal structure; (c) contacting the zeolite from step (b) with a dealuminating agent to which the said foreign material is substantially inert under the process conditions for a sufficient time and under suitable process conditions as to remove at least some of the aluminium from the zeolite; and (d) subjecting the thus partially de-aluminated zeolite to further treatment whereby to remove substantially the remainder of said foreign material.
Claim 2
Dependent Claim
121 words
A process for the controlled removal of aluminium from a crystalline aluminosilicate zeolite which comprises: (a) subjecting the zeolite to a treatment whereby the pore system of the zeolite is filled substantially completely with a foreign material; (b) selectively removing a portion of said foreign material from an outer zone of the zeolite crystal structure; (c) contacting the zeolite from step (b) with a dealuminating agent to which the said foreign material is substantially inert under the process conditions for a sufficient time and under suitable process conditions as to remove at least some of the aluminium from the zeolite; and (d) subjecting the thus partially de-aluminated zeolite to further treatment whereby to remove substantially the remainder of said foreign material.
Claim 3
Dependent Claim
20 words
A process as claimed in claim 1 in which steps (b) and (c) of the process are carried out simultaneously.
Claim 4
Dependent Claim
40 words
A process as claimed in claim 1 or 2 in which the foreign material is selected from carbonaceous residues ("coke"), organic materials and materials substantially immiscible with the dealuminating agent or the medium in which the dealuminating agent is used.
Claim 5
Dependent Claim
112 words
A process as claimed in any one of claims 1 to 3 which comprises: (a) subjecting a zeolite to a coking treatment in which a carbonaceous residue ("coke") is deposited throughout the zeolite crystal to a degree which substantially completely blocks access to the zeolite pore structure; (b) selectively de-coking the coked zeolite whereby to partially remove the coke deposited in step (a); (c) contacting the partially de-coked zeolite with a dealuminating agent for a sufficient time and under suitable process conditions as to remove at least some of the aluminium from the zeolite; and (d) subjecting the zeolite to further de-coking whereby to produce a dealuminated zeolite substantially free of coke.
Claim 6
Dependent Claim
33 words
A process as claimed in claim 4 in which coking is effected at a temperature greater than 300°C using a coking agent which is an alcohol or a hydrocarbon or a mixture thereof.
Claim 7
Dependent Claim
31 words
A process as claimed in claim 4 or 5 in which the decoking of step (b) is carried out in the presence of a gas stream comprising oxygen at elevated temperature.
Claim 8
Dependent Claim
117 words
A process as claimed in any one of claims 1 to 3 which comprises: (a) selecting a zeolite containing organic material within at least part of its pore system and, if necessary, treating said zeolite with further organic material whereby to substantially fill said zeolite pore system with organic material; (b) selectively removing a portion of said organic material from an outer zone of the zeolite crystal structure; (c) contacting the zeolite product from step (b) with a dealuminating agent whereby to remove at least some of the aluminium from the zeolite; and (d) subjecting the zeolite product from step (c) to treatment to remove substantially completely remaining organic material from the pore system of said zeolite.
Claim 9
Dependent Claim
22 words
A process as claimed in claim 7 in which the organic material comprises a material used in the synthesis of the zeolite.
Claim 10
Dependent Claim
19 words
A process as claimed in claim 7 or 8 in which the organic material is a quaternary ammonium cation.
Claim 11
Dependent Claim
38 words
A process as claimed in any one of the preceding claims in which the dealuminating agent used in step (c) is selected from metal halides, oxyhalides, acid halides, phosgene, thionyl chloride, complexing agents, mineral acids, steam and halogens.
Claim 12
Dependent Claim
38 words
A process as claimed in any one of the preceding claims in which between steps (b) and (c) of the process metallic cations other than aluminium which may be present in the zeolite are partially or completely removed.
Claim 13
Dependent Claim
20 words
A process as claimed in any one of the preceding claims in which after step (d) the zeolite is acid-washed.
Claim 14
Dependent Claim
64 words
An aluminosilicate zeolite which has been treated by a process as claimed in any one of claims 1 to 12 and which comprises an inner core having a silica to alumina mole ratio substantially characteristic of the untreated zeolite and an outer skin which has been at least partially dealuminated and which has a higher silica to alumina mole ratio than said inner core.
Claim 15
Dependent Claim
30 words
A process for the disproportionation of toluene to benzene and xylene which comprises reacting toluene under disproportionation conditions using a catalyst which comprises a zeolite as claimed in claim 13.
References Cited (Backward Citations)
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