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US3758604A
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Isomerization-fractionation process
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1972-03-15
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Granted: 1973-09-11
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Expires: 1992-03-15
Abstract
Abstract A process for separating isobutylene from C4 feeds by subjecting the feed to isomerization using a low-temperature active isomerization catalyst, reducing the butene-1 level followed by fractionation of the isomerized feed and again isomerizing the top fraction containing isobutylene and remaining butene-1 and isolating isobutylene therefrom. Preferably the isomerization of the feed is carried out in two stages under adiabatic conditions, with cooling in between.
Inventors
- 👤 N Sprecher
- 👤 J Cotter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:39
CPC Classifications
C; C07; C07C; C07C11/00; C07C11/02; C07C11/08; C07C11/09; C07C5/00; C07C5/22; C07C5/23; C07C5/25; C07C5/2506; C07C5/2562; C07C5/2581; C07C7/00; C07C7/005
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
33 words
A continuous process according to claim 1, wherein the isomerization of the C4-mixture is carried out in two steps and in the first step the major amount of butene-1 is isomerized to butenes-2.
Claim 2
Dependent Claim
28 words
A continuous process according to claim 2, wherein 90 - 100 percent of the isomerization (compared with the thermo-dynamic equilibrium values) is carried out in the first step.
Claim 3
Dependent Claim
21 words
A continuous process according to claim 2, wherein the isomerization is carried out in two separate vessels separated by a heat-exchanger.
Claim 4
Dependent Claim
20 words
A continuous process according to claim 4, wherein the isomerizations are carried out under adiabatic conditions with cooling in between.
Claim 5
Dependent Claim
20 words
A continuous process according to claim 2, wherein the temperature rise in the second step is no more than 10*C.
Claim 6
Dependent Claim
27 words
A continuous process according to claim 2, wherein the isomerization in the second step is carried out at a temperature in the range of 0 to 75*C.
Claim 7
Dependent Claim
23 words
A continuous process according to claim 1, wherein the C4-feed mixture contains isobutylene and/or butadiene, which are separated by fractionation after the isomerization.
Claim 8
Dependent Claim
56 words
A continuous process according to claim 1, wherein the isomerization steps are conducted in either vapour or liquid phase operation at temperatures from about -50* to about 200*C, at space velocities from about 0.4 to about 40 liquid volumes of olefin per volume of catalyst per hour, at pressures from about atmospheric to about 250 psig.
Claim 9
Dependent Claim
20 words
A process according to claim 1, wherein an isomerization catalyst is employed which is active at a temperature below 100*C.
Claim 10
Dependent Claim
170 words
A process according to claim 1, wherein a C4-feed is isomerized in a first step in the presence of a catalyst in such a way that the butene-1 level is reduced to a value of 5 - 15 percent of the original content, cooling the isomerized feed to remove heat of reaction and subjecting the cooled isomerized feed to a second isomerization in the presence of a catalyst active at low temperatures, the reaction temperature in the second step being in the range of 0 to 75*C, both steps being carried out under adiabatic conditions, feeding the mixture containing less than 5 percent of the original butene-1 content in a fractionation tower to recover as a top fraction isobutylene plus traces of butene-1 and as a bottom fraction the butenes-2 and other compounds, isomerizing the top fraction at low temperatures in the range of 0 to 75*C in the presence of a low-temperature active catalyst, recirculating part of the isomerized top fraction and recovering substantially pure isobutylene by further fractionation.
Claim 11
Dependent Claim
23 words
The process according to claim 1 wherein the catalyst is cobalt II acetyl acetonate supported on Si02 and reduced by an alkyl alumina.
Claim 12
Dependent Claim
13 words
The process according to claim 1 wherein the catalyst is sodium on alumina.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |