US4413147A
Expired / Lapsed
US
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Conversion of isobutane to methacrolein
Assignee: Lyondell Chemical Technology LP
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Filing: 1982-04-14
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Granted: 1983-11-01
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Expires: 2002-04-14
Abstract
Abstract Isobutane is converted to methacrolein in an integrated two-step process wherein isobutane is dehydrogenated in a first step to isobutylene, hydrogen, and by-products and the reaction effluent is passed directly into a second step where isobutylene is oxidized to methacrolein without significant oxidation of the hydrogen and by-products. The methacrolein and by-products may be separated and the unreacted isobutylene and isobutane recycled to the first step. Alternatively, the effluent from the second step may be used as feed to a further oxidation step for conversion of methacrolein to methacrylic acid. In one embodiment, the hydrogen produced in the first step is oxidized using the excess oxygen from the second step under conditions selected to avoid loss of the C 4 components. In an alternative embodiment, the unreacted isobutane and isobutylene are absorbed and separated from the remaining components before being recycled to the first step.
Inventors
- 👤 Sargis Khoobiar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:12
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/25; C07C51/252; B; B01; B01J; B01J23/00; B01J23/002; B01J27/00; B01J27/14; B01J27/186; B01J27/188; B01J27/19; B01J27/192; B01J27/195; B01J27/198; B01J27/199; C07C45/00; C07C45/27; C07C45/32; C07C45/33; C07C45/34; C07C45/35; C07C45/37; C07C5/00; C07C5/32; C07C5/327; C07C5/333; C07C5/3332; C07C5/3335; C07C5/3337; B01J2523/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
122 words
A process for the preparation of methacrolein from isobutane comprising: (a) dehydrogenating isobutane to isobutylene, optionally in the presence of steam, over a dehydrogenation catalyst comprising a Group VIII noble metal or base metal oxide on a support at a temperature in the range of about 300°-700° C. and up to about 10 kg/cm 2 gauge pressure to form an effluent stream comprising isobutylene, hydrogen, carbon oxides and unreacted isobutane; (b) mixing oxygen and optionally steam with said effluent stream of (a) and passing the mixture over a molybdenum-based oxidation catalyst at conditions selected to produce methacrolein and producing an effluent stream comprising methacrolein, unreacted isobutylene and isobutane, and oxygen, and carbon oxides; (c) recovering the methacrolein from said effluent of (b).
Claim 2
Dependent Claim
122 words
A process for the preparation of methacrolein from isobutane comprising: (a) dehydrogenating isobutane to isobutylene, optionally in the presence of steam, over a dehydrogenation catalyst comprising a Group VIII noble metal or base metal oxide on a support at a temperature in the range of about 300°-700° C. and up to about 10 kg/cm 2 gauge pressure to form an effluent stream comprising isobutylene, hydrogen, carbon oxides and unreacted isobutane; (b) mixing oxygen and optionally steam with said effluent stream of (a) and passing the mixture over a molybdenum-based oxidation catalyst at conditions selected to produce methacrolein and producing an effluent stream comprising methacrolein, unreacted isobutylene and isobutane, and oxygen, and carbon oxides; (c) recovering the methacrolein from said effluent of (b).
Claim 3
Dependent Claim
61 words
The process of claim 1 further comprising the steps of: (d) separating from said effluent of (b) after recovery of methacrolein therefrom the hydrogen produced in (a), the carbon oxides produced in (a) and (b), and the unreacted oxygen of (b); and (e) returning as feed to (a) the effluent of (b) after recovering methacrolein, hydrogen, oxygen, and carbon oxides therefrom.
Claim 4
Dependent Claim
32 words
The process of claim 1 wherein said dehydrogenation step (a) is fed with isobutane and steam in a ratio of about 1/1 to 1/10 and a pressure about 2-10 kg/cm 2 gauge.
Claim 5
Dependent Claim
21 words
The process of claim 1 wherein said oxidation step (b) is carried out at 300°-400° C. and 1-8 kg/cm 2 gauge.
Claim 6
Dependent Claim
27 words
The process of claim 1 wherein said oxidation catalyst of (b) comprises the elements molybdenum, bismuth, cobalt, iron, nickel, thallium, antimony, and one or more alkali metals.
Claim 7
Dependent Claim
46 words
The process of claim 1 wherein said oxygen and hydrogen are separated from said effluent of (b) after recovery of methacrolein therefrom by reaction to form water over an oxidation catalyst under conditions selected to oxidize said hydrogen while leaving said isobutylene and isobutane substantially unoxidized.
Claim 8
Dependent Claim
15 words
The process of claim 6 wherein said oxidation catalyst is platinum or palladium on alumina.
Claim 9
Dependent Claim
19 words
The process of claim 7 wherein said oxidation reaction is initiated at a temperature up to about 400° C.
Claim 10
Dependent Claim
33 words
The process of claim 6 wherein the amount of oxygen added in step (b) is adjusted to provide an amount in said effluent of (b) substantially equivalent to the hydrogen produced in (a).
Claim 11
Dependent Claim
57 words
The process of claim 1 further comprising the steps of: (d) separating from said effluent of (b) after recovery of methacrolein therefrom the unreacted isobutane and isobutylene by absorption in a liquid and thereafter stripping said absorbed isobutane and isobutylene from said liquid and; (e) returning as feed to (a) the stripped isobutane and isobutylene from (d).
Claim 12
Dependent Claim
16 words
The process of claim 10 wherein said liquid is a C 8 -C 10 paraffin oil.
Claim 13
Dependent Claim
43 words
The process of claim 1 wherein the effluent of (a) is mixed with molecular oxygen and passed over an oxidation catalyst under conditions selected to selectively oxidize said hydrogen while leaving said isobutylene and isobutane substantially unoxidized and thereafter carrying out step (b).
Claim 14
Dependent Claim
15 words
The process of claim 12 wherein said oxidation catalyst is platinum or palladium on alumina.
Claim 15
Dependent Claim
20 words
The process of claim 13 wherein said selective oxidation reaction is initiated at a temperature up to about 400° C.
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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) | 1986-10-31 | 1987-05-02 | 1987-11-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-31 | 1991-05-02 | 1991-11-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-31 | 1995-05-02 | 1995-11-01 | $7700.00 | Window Closed / Lapsed |