Patent US4684619A successfully refreshed from Google Patents.
US4684619A
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Process for making a dehydrogenation catalyst having improved moisture stability
Assignee: Dow Chemical Co
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Filing: 1986-09-30
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Granted: 1987-08-04
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Expires: 2006-09-30
Abstract
Abstract A method for preparing an iron oxide containing dehydrogenative catalyst having improved moisture stability which comprises calcining by a two step method. The temperature of calcination is maintained at from about 250° to about 600° C. in the first step and from about 700° to about 800° C. in the second step. The effectiveness of the catalyst is not substantially changed from that of the single step calcination known to the art while the moisture stability is improved.
Inventors
- 👤 Stanley E. Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:39
CPC Classifications
B; B01; B01J; B01J37/00; B01J37/0009; B01J37/0018; B01J23/00; B01J23/70; B01J23/76; B01J23/78; C; C07; C07C; C07C5/00; C07C5/32; C07C5/327; C07C5/333; C07C5/3332
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
142 words
In a process for making an iron oxide-containing dehydrogenation catalyst wherein an alkali metal carbonate is employed as a promoter, organic materials are employed as porosity control agents and the constituents are combined, formed into a particulate mass and calcined at temperatures sufficient to oxidize the organic materials and convert the carbonate to an oxide, the improvement which comprises conducting the calcining process in two steps, wherein the particulate mass is heated (1) to a temperature in the range of from 250° to about 600° C. for a time of from about 30 minutes to about 4 hours which is sufficient to oxidize said organic materials and thereafter (2) to a temperature of from 700° to 800° C. for a time of from about 10 to about 60 minutes which is sufficient to convert substantially all carbonates present to the corresponding oxides.
Claim 2
Dependent Claim
142 words
In a process for making an iron oxide-containing dehydrogenation catalyst wherein an alkali metal carbonate is employed as a promoter, organic materials are employed as porosity control agents and the constituents are combined, formed into a particulate mass and calcined at temperatures sufficient to oxidize the organic materials and convert the carbonate to an oxide, the improvement which comprises conducting the calcining process in two steps, wherein the particulate mass is heated (1) to a temperature in the range of from 250° to about 600° C. for a time of from about 30 minutes to about 4 hours which is sufficient to oxidize said organic materials and thereafter (2) to a temperature of from 700° to 800° C. for a time of from about 10 to about 60 minutes which is sufficient to convert substantially all carbonates present to the corresponding oxides.
Claim 3
Dependent Claim
32 words
The process of claim 1 wherein the products of oxidation in the first step and the carbon dioxide of the second step are removed simultaneously as they are evolved from said mass.
Claim 4
Dependent Claim
23 words
The process of claim 2 wherein the removal of evolved products of oxidation is accomplished by a flow of gas over said mass.
Claim 5
Dependent Claim
11 words
The process of claim 3 wherein the flowing gas is air.
Claim 6
Dependent Claim
28 words
The process of claim 2 wherein the temperature of steps 1 and 2 are about 350° to about 600° C. and about 750° to about 790° C., respectively.
References Cited (Backward Citations)
US3703593A
Cited
US4503163A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |