US4169865A
Expired / Lapsed
US
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Production of aromatic hydrocarbons
Assignee: Imperial Chemical Industries Ltd
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Filing: 1978-06-13
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Granted: 1979-10-02
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Expires: 1998-06-13
Abstract
Abstract A process for the dimerization and cyclization of isobutene to form, as preferred product, paraxylene in which the whole of the product of isobutene dimerization (including unreacted feedstock) is contacted with a catalyst for the cyclization of the isobutene dimer. The process is operable in a single dimerization/cyclization stage or in separate dimerization and cyclization stages with no intermediate separation of products. Optionally, the isobutene feedstock is provided by dehydrogenation of isobutane, unreacted isobutane in the resulting feedstock being carried through the dimerization/cyclization and eventually recycled.
Inventors
- 👤 John R. Bamforth
- 👤 Raymond Higgins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:08
CPC Classifications
C; C07; C07C; C07C15/00; C07C15/02; C07C15/067; C07C15/08; C07C2/00; C07C2/76; C07C2/82; C07C2/84; C07C5/00; C07C5/32; C07C5/327; C07C5/333; C07C5/3332; C07C5/3335; C07C5/3337; C07C5/373; C07C5/393; C07C5/41; C07C2521/00; C07C2521/02; C07C2521/04; C07C2521/10; C07C2523/00; C07C2523/06; C07C2523/08; C07C2523/14; C07C2523/16; C07C2523/18; C07C2523/24; C07C2523/26; C07C2527/00; C07C2527/14; C07C2527/16; C07C2527/167; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/52
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
81 words
A process for the production of aromatic hydrocarbons which comprises contacting a feed comprising isobutene at elevated temperature and in the presence of added oxygen with a catalytic amount of a catalyst for the oxidative dimerisation of olefins, to form a product comprising at least one dimer of isobutene and contacting the whole of said product (including any unreacted hydrocarbon feedstock) with a non-acid catalyst for the cyclisation of the isobutene dimer whereby to form a final product comprising aromatic hydrocarbons.
Claim 2
Dependent Claim
81 words
A process for the production of aromatic hydrocarbons which comprises contacting a feed comprising isobutene at elevated temperature and in the presence of added oxygen with a catalytic amount of a catalyst for the oxidative dimerisation of olefins, to form a product comprising at least one dimer of isobutene and contacting the whole of said product (including any unreacted hydrocarbon feedstock) with a non-acid catalyst for the cyclisation of the isobutene dimer whereby to form a final product comprising aromatic hydrocarbons.
Claim 3
Dependent Claim
44 words
A process as claimed in claim 1 in which the process is operated in two sequential stages comprising a first stage for the oxidative dimerisation of isobutene and a second stage for the catalytic aromatisation of the dimer product from the first, dimerisation, stage.
Claim 4
Dependent Claim
35 words
A process as claimed in claim 2 in which the catalyst for the oxidative dimerisation stage is a metal oxide selected from one or more oxides of metals of Group VIII of the Periodic Table.
Claim 5
Dependent Claim
38 words
A process as claimed in claim 3 in which the catalyst comprises bismuth oxide which is present in a partially reduced state, the average degree of reduction throughout the whole bed being in the range 1 to 70%.
Claim 6
Dependent Claim
31 words
A process as claimed in claim 2 in which the degree of oxygen conversion, measured at the downstream end of the dimerisation catalyst bed is in the range 90 to 99%.
Claim 7
Dependent Claim
49 words
A process as claimed in claim 2 in which, in the dimerisation stage, the reaction temperature is in the range 400° to 600° C., the olefin partial pressure is in the range 0.20 to 0.99 atmospheres, and the oxygen partial pressure is in the range 0.01 to 0.30 atmospheres.
Claim 8
Dependent Claim
61 words
A process as claimed in claim 2 in which the aromatisation stage is carried out in the presence of a non acid catalyst selected from chromia-alumina, magnesium oxide, gallium, zinc, germanium, indium, tin and compounds of these metals, at a reaction temperature in the range 300° to 600° C. and in the absence of, or with a low concentration, of oxygen.
Claim 9
Dependent Claim
27 words
A process as claimed in claim 1 in which the process is operated as a single stage process using either a mixed or a dual-function dimerisation/cyclisation catalyst.
Claim 10
Dependent Claim
29 words
A process as claimed in claim 8 in which the catalyst is selected from bismuth phosphate, bismuth-tin-oxygen, bismuth-gallium-oxygen, bismuth-germanium-oxygen, bismuth-zinc-oxygen compositions and a mixture of chromia-alumina and bismuth oxide.
Claim 11
Dependent Claim
36 words
A process as claimed in claim 8 in which the catalyst comprises bismuth oxide in a partially reduced state, the average degree of reduction over the whole catalyst bed being in the range 1 to 70%.
Claim 12
Dependent Claim
49 words
A process as claimed in claim 8 in which the degree of oxygen conversion is in the range 90 to 99%, the partial pressure of oxygen is in the range of 0.01 to 0.30 atmospheres, and the partial pressure of olefin is in the range 0.20 to 0.99 atmospheres.
Claim 13
Dependent Claim
33 words
A process as claimed in claim 1 in which the isobutene feedstock is provided by a feed of isobutane which is subjected to dehydrogenation to convert it, at least in part to isobutene.
Claim 14
Dependent Claim
52 words
A process as claimed in claim 12 in which unreacted isobutane is separated with unreacted isobutene from the products of the dimerisation/aromatisation stage (one-stage process and aromatisation stage (two-stage process) and recycled to one or partially to both of (i) the isobutane dehydrogenation stage or (ii) the dimerisation/aromatisation stage or dimerisation stage.
Claim 15
Dependent Claim
26 words
A process as claimed in claim 1 in which unreacted isobutene is recycled to the dimerisation/aromatisation stage (one-stage process) or to the dimerisation stage (two-stage process).
References Cited (Backward Citations)
US3644550A
Cited
US4056575A
Cited
US4036902A
Cited
US4056576A
Cited
US4079097A
Cited
US4046833A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-10-01 | 1983-04-02 | 1983-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-01 | 1987-04-02 | 1987-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-01 | 1991-04-02 | 1991-10-02 | $7700.00 | Window Closed / Lapsed |