Patent US4952719A successfully refreshed from Google Patents.
US4952719A
Expired / Lapsed
US
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Process for the preparation of halo aromatic compounds
Assignee: Occidental Chemical Corp
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Filing: 1989-01-27
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Granted: 1990-08-28
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Expires: 2009-01-27
Abstract
Abstract A process for the preparation of 3-chloro-4,5-difluorobenzonitrile comprising the steps of (a) reacting an alkali metal fluoride with 4-chloro-3,5-dinitrobenzonitrile to form a 4-fluoro-3,5-dinitrobenzonitrile product; (b) chlorodenitrating the 4-fluoro product of step (a) to form the corresponding 3,5-dichloro-4-fluorobenzonitrile compound; and (c) reacting the 3,5-dichloro-4-fluorobenzonitrile compound prepared in step (b) with an alkali metal fluoride to form 3-chloro-4,5-difluorobenzonitrile.
Inventors
- 👤 James J. Maul
- 👤 David Y. Tang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:44
CPC Classifications
C; C07; C07C; C07C255/00; C07C17/00; C07C17/093; C07C17/20; C07C17/202; C07C17/208
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
74 words
A process for the preparation of 3-chloro-4,5-difluoro-benzonitrile which comprises the steps of (a) reacting an alkali metal fluoride with 4-chloro-3,5-dinitrobenzonitrile at a temperature of from about 50° to about 300° Celsius to form 4-fluoro-3,5-dinitro-benzonitrile; (b) chlorodenitrating the 4-fluoro-e,5-dinitro product of step (a) to form 3,5-dichloro-4-fluorobenzonitrile; and (c) reacting the 3,5-dichloro-4-fluorobenzonitrile compound prepared in step (b) at a temperature of from about 50° to about 300° Celsius with an alkali metal fluoride to form 3-chloro-4,5-difluorobenzonitrile.
Claim 2
Dependent Claim
74 words
A process for the preparation of 3-chloro-4,5-difluoro-benzonitrile which comprises the steps of (a) reacting an alkali metal fluoride with 4-chloro-3,5-dinitrobenzonitrile at a temperature of from about 50° to about 300° Celsius to form 4-fluoro-3,5-dinitro-benzonitrile; (b) chlorodenitrating the 4-fluoro-e,5-dinitro product of step (a) to form 3,5-dichloro-4-fluorobenzonitrile; and (c) reacting the 3,5-dichloro-4-fluorobenzonitrile compound prepared in step (b) at a temperature of from about 50° to about 300° Celsius with an alkali metal fluoride to form 3-chloro-4,5-difluorobenzonitrile.
Claim 3
Dependent Claim
19 words
A process according to claim 1, wherein the alkali metal fluoride of steps (a) and (b) is potassium fluoride.
Claim 4
Dependent Claim
46 words
A process according to claim 1, wherein the reactions of steps (a) and (c) are carried out neat at a temperature of 140.5° to about 155° Celsius for the reaction of step (a) and about 170° to about 270° Celsius for the reaction of step (c).
Claim 5
Dependent Claim
52 words
A process according to claim 1, wherein the reactions of steps (a) and (c) are carried out in the presence of a solvent at a temperature of about 75° to about 155° Celsius for the reaction of step (a) and about 170° to about 270° Celsius for the reaction of step (c).
Claim 6
Dependent Claim
52 words
A process according to claim 1, wherein the reaction of step (a) is carried out neat at a temperature of about 75° to about 155° Celsius in the presence of a solvent and the reaction of step (c) is carried out neat at a temperature of about 170° to about 270° Celsius.
Claim 7
Dependent Claim
52 words
A process according to claim 1, wherein the reaction of step (a) is carried out neat at a temperature of about 140.5° to about 155° Celsius in the presence of a solvent and the reaction of step (c) is carried out neat at a temperature of about 170° to about 270° Celsius.
Claim 8
Dependent Claim
30 words
A process according to claim 1, wherein the chlorodenitration reaction of step (b) is carried out in the vapor phase at a temperature of about 250° to about 450° Celsius.
Claim 9
Dependent Claim
36 words
A process according to claim 7, wherein the chlorodenitration reaction of step (b) is carried out in the vapor phase by reacting Cl 2 with 4-fluoro-3,5-dinitrobenzonitrile at a temperature of about 290° to about 410° Celsius.
Claim 10
Dependent Claim
27 words
A process for the preparation of 3-chloro-4,5-difluorobenzonitrile which comprises reacting 3,5-dichloro-4-fluoro-benzonitrile with an alkali metal fluoride at a temperature of from about 50° to about 300° Celsius.
Claim 11
Dependent Claim
27 words
A process for the preparation of 3-chloro-4,5-difluorobenzonitrile which comprises reacting 3,5-dichloro-4-fluoro-benzonitrile with an alkali metal fluoride at a temperature of from about 50° to about 300° Celsius.
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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |