US3919398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recovery of hydrogen bromide from aromatic bromides
Assignee: Dow Chemical Co
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Filing: 1974-08-29
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Granted: 1975-11-11
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Expires: 1994-08-29
Abstract
Abstract A method of recovering bromine as hydrogen bromide from aromatic bromides. The method involves reacting the aromatic bromide with hydrogen at a temperature within the range of from about 200* to about 600* C in the presence of a palladium activated catalyst.
Inventors
- 👤 Ralph A Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:17
CPC Classifications
C; C01; C01B; C01B7/00; C01B7/09; C01B7/093
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
41 words
A PROCESS COMPRISINGREACTING AN AROMATIC BROMIDE WITH HYDROGEN AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 200* TO ABOUT 600*C IN THE PRESENCE OF A PALLADIUM ACTIVATED CATALYST TO FORM HYDROGEN BROMIDE, AND RECOVERING HYDROGEN BROMIDE FROM THE REACTION PRODUCTS.
Claim 2
Dependent Claim
41 words
A PROCESS COMPRISINGREACTING AN AROMATIC BROMIDE WITH HYDROGEN AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 200* TO ABOUT 600*C IN THE PRESENCE OF A PALLADIUM ACTIVATED CATALYST TO FORM HYDROGEN BROMIDE, AND RECOVERING HYDROGEN BROMIDE FROM THE REACTION PRODUCTS.
Claim 3
Dependent Claim
14 words
The process of claim 1 wherein the catalyst is a water soluble palladium compound.
Claim 4
Dependent Claim
30 words
The process of claim 2 wherein the palladium compound is in combination with a member selected from the group consisting of the oxides of chromium, vanadium, tungsten, cerium and molybdenum.
Claim 5
Dependent Claim
28 words
The process of claim 3 wherein the palladium compound-oxide combination is further in combination with a substrate selected from the group consisting of silica gel, alumina and charcoal.
Claim 6
Dependent Claim
31 words
The process of claim 2 wherein the palladium compound is in combination with a member selected from the group consisting of Cr2O3, V2O3, V2O5, MoO3, Mo3O8, MoO2, CeO2, WO2 and W2O5.
Claim 7
Dependent Claim
37 words
The process of claim 5 wherein the catalytic combination contains by weight about 0.1 to about 1 per cent PdCl2, about 5 to about 25 per cent Cr2O3 and about 75 to about 95 per cent Al2O3.
Claim 8
Dependent Claim
11 words
The process of claim 2 wherein a palladium compound is PdCl2.
Claim 9
Dependent Claim
16 words
The process of claim 1 wherein the catalyst is a combination of PdCl2, Cr2O3 and Al2O3.
Claim 10
Dependent Claim
25 words
The process of claim 8 wherein PdCl2 is present in an amount of from about 0.1 to about 2 weight per cent of the reactants.
Claim 11
Dependent Claim
12 words
The process of claim 8 wherein the aromatic bromide is 2,3, 5-tribromoparaxylene.
Claim 12
Dependent Claim
20 words
The process of claim 10 wherein the reaction temperature is within the range of from about 280* to about 400*C.
Claim 13
Dependent Claim
28 words
The process of claim 11 wherein the molar ratio of hydrogen to 2,3,5-tribromoparaxylene is within the range of from about 1.5 to 1.0 to about 10 to 1.0.
Claim 14
Dependent Claim
12 words
The process of claim 1 wherein the aromatic bromide is brominated methylbenzene.
Claim 15
Dependent Claim
12 words
The process of claim 1 wherein the aromatic bromide is brominated 1,4-dimethylbenzene.
Claim 16
Dependent Claim
14 words
The process of claim 1 wherein the aromatic bromide is the 2,3-isomer of 2,5-dibromoparaxylene.
Claim 17
Dependent Claim
12 words
The process of claim 1 wherein the aromatic bromide is 2,3, 5-tribromoparaxylene.
Claim 18
Dependent Claim
29 words
The process of claim 1 wherein the molar ratio of hydrogen to the aromatic bromide is within the range from about 1.1 to 1.0 to about 40 to 1.0.
Claim 19
Dependent Claim
29 words
The process of claim 1 wherein the molar ratio of hydrogen to the aromatic bromide is within the range from about 1.5 to 1.0 to about 10 to 1.0.
Claim 20
Dependent Claim
20 words
The process of claim 1 wherein the reaction temperature is within the range of from about 280* to about 400*C.
Claim 21
Dependent Claim
27 words
The process of claim 1 wherein the palladium compound is further in combination with a substrate selected from the group consisting of silica gel, alumina and charcoal.
Claim 22
Dependent Claim
25 words
The process of claim 8 wherein the Al2O3 is a particulate with a size within the range of from about 3 to about 20 mesh.
Claim 23
Dependent Claim
20 words
The process of claim 1 wherein the reaction temperature is within the range of from about 280* to about 400*C.
References Cited (Backward Citations)
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US3199953A
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US3453073A
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US3839547A
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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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |