US4918251A
Expired / Lapsed
US
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Preparation of 2-halofluorobenzene
Assignee: Mallinckrodt Chemical Inc
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Filing: 1989-04-04
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Granted: 1990-04-17
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Expires: 2009-04-04
Abstract
Abstract A process for producing 2-halofluorobenzene from 2,4-dihalofluorobenzenes comprises treating an aqueous slurry of 2,4-dihalofluorobenzene with hydrogen at an elevated temperature in the presence of a transition metal supported on a carbon catalyst. The process produces a mixture including fluorobenzene and 2-halofluorobenzene. The 2-halofluorobenzene can be separated from the mixture by conventional means such as distillation. Optionally, the fluorobenzene also can be recovered.
Inventors
- 👤 Robert Halvachs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:11
CPC Classifications
C; C07; C07C; C07C17/00; C07C17/23
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
59 words
A process for preparing a 2-halofluorobenzene which comprises: treating with hydrogen gas an aqueous slurry of 2,4-dihalofluorobenzene; said treatment being carried out in the presence of a transition metal catalyst, wherein said transition metal is selected from the group consisting of platinum and palladium, and at a temperature in the range of about 25° C. to about 75° C.
Claim 2
Dependent Claim
59 words
A process for preparing a 2-halofluorobenzene which comprises: treating with hydrogen gas an aqueous slurry of 2,4-dihalofluorobenzene; said treatment being carried out in the presence of a transition metal catalyst, wherein said transition metal is selected from the group consisting of platinum and palladium, and at a temperature in the range of about 25° C. to about 75° C.
Claim 3
Dependent Claim
19 words
The process of claim 1, further comprising the step of separating the 2-halofluorobenzene from the treated slurry by distillation.
Claim 4
Dependent Claim
25 words
The process of claim 2, further comprising the step of adding sodium chloride to said aqueous solution prior to treating said solution with hydrogen gas.
Claim 5
Dependent Claim
32 words
The process of claim 3, wherein said treatment with hydrogen gas comprises forcing said hydrogen gas into said aqueous slurry at a pressure of at least about 20 psig H 2 .
Claim 6
Dependent Claim
33 words
The process of claim 4, wherein said hydrogen gas is forced into said aqueous slurry at a pressure from at least about 20 psig H 2 to about 150 psig H 2 .
Claim 7
Dependent Claim
10 words
The process of claim 5, wherein said 2,4-dihalofluorobenzene comprises 2,4-dibromofluorobenzene.
Claim 8
Dependent Claim
15 words
The process of claim 6, wherein said slurry comprises a mixture of 2,6-dibromofluorobenzene and 2,4-dibromofluorobenzene.
Claim 9
Dependent Claim
16 words
The process of claim 6, wherein said slurry comprises a mixture of 2,6-dibromofluorobenzene, 2,4-dibromofluorobenzene and 3,4-dibromofluorobenzene.
Claim 10
Dependent Claim
16 words
The process of claim 5 wherein the reaction temperature is about 55° C. to 65° C.
Claim 11
Dependent Claim
11 words
The process of claim 5, wherein the transition metal is palladium.
Claim 12
Dependent Claim
47 words
A process for preparing 2-bromofluorobenzene which comprises: (a) forming an aqueous slurry of a mixture of 2,6-dibromofluorobenzene, 3,4-dibromobenzene and 2,4-dibromobenzene; (b) mixing a palladium-on-carbon catalyst with said slurry; (c) heating said slurry to about 60° to 65° C., and (d) treating said heated slurry with hydrogen gas.
Claim 13
Dependent Claim
47 words
A process for preparing 2-bromofluorobenzene which comprises: (a) forming an aqueous slurry of a mixture of 2,6-dibromofluorobenzene, 3,4-dibromobenzene and 2,4-dibromobenzene; (b) mixing a palladium-on-carbon catalyst with said slurry; (c) heating said slurry to about 60° to 65° C., and (d) treating said heated slurry with hydrogen gas.
Claim 14
Dependent Claim
10 words
The process of claim 11, further comprising recovering said 2-bromofluorobenzene.
Claim 15
Dependent Claim
16 words
The process of claim 11, further comprising adding sodium chloride to said mixture prior to heating.
Claim 16
Dependent Claim
17 words
The process of claim 1, 5, 11 or 12, further comprising recovering fluorobenzene from said treated slurry.
Claim 17
Dependent Claim
31 words
The process of claim 11, wherein said hydrogen gas treatment comprises forcing said hydrogen gas into said slurry by applying a pressure of at least about 20 psig H 2 .
Claim 18
Dependent Claim
21 words
The process of claim 15, wherein said forcing pressure is from about 20 psig to about 150 psig H 2 .
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |