US5091580A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of 2,6-difluoroaniline
Assignee: Corteva Agriscience LLC
•
Filing: 1991-03-27
•
Granted: 1992-02-25
•
Expires: 2011-03-27
Abstract
Abstract 2,6-Difluoroaniline is prepared from 1,2,3-trichlorobenzene by partial fluorine exchange to a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene, amination of the chloro substituents, and separation of the desired product from the isomeric 2,3-difluoroaniline. By incorporating a selective reduction into the process immediately after the partial fluorine exchange, the undesirable 2,3-difluorochlorobenzene is converted into valuable ortho-difluorobenzene and the 2,3-difluoroaniline isomer is avoided.
Inventors
- 👤 R. Garth Pews
- 👤 James A. Gall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:51
CPC Classifications
C; C07; C07C; C07C211/00; C07C211/43; C07C211/44; C07C211/45; C07C17/00; C07C17/093; C07C17/20; C07C17/202; C07C17/208; C07C209/00; C07C209/04; C07C209/06; C07C209/10; C07C25/00; C07C25/02; C07C25/13
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
95 words
A process for preparing 2,6-difluoroaniline from 1,2,3-trichlorobenzene which comprises the following sequential steps: (a) exchanging two chlorines from 1,2,3-trichlorobenzene with fluorines under conditions which give a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene; (b) selectively reducing the chlorine from the 2,3-difluorochlorobenzene in admixture with 2,6-difluorochlorobenzene by contacting the mixture with a hydrogen source in the presence of a palladium catalyst in an inert organic solvent from ambient temperature to about 150° C. to give a mixture of 2,6-difluorochlorobenzene and ortho-difluorobenzene; (c) separating the ortho-difluorobenzene from the 2,6-difluorochlorobenzene; and (d) aminating the 2,6-difluorochlorobenzene under conditions which give 2,6-difluoroaniline.
Claim 2
Dependent Claim
95 words
A process for preparing 2,6-difluoroaniline from 1,2,3-trichlorobenzene which comprises the following sequential steps: (a) exchanging two chlorines from 1,2,3-trichlorobenzene with fluorines under conditions which give a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene; (b) selectively reducing the chlorine from the 2,3-difluorochlorobenzene in admixture with 2,6-difluorochlorobenzene by contacting the mixture with a hydrogen source in the presence of a palladium catalyst in an inert organic solvent from ambient temperature to about 150° C. to give a mixture of 2,6-difluorochlorobenzene and ortho-difluorobenzene; (c) separating the ortho-difluorobenzene from the 2,6-difluorochlorobenzene; and (d) aminating the 2,6-difluorochlorobenzene under conditions which give 2,6-difluoroaniline.
Claim 3
Dependent Claim
112 words
A process for preparing 2,6-difluoroaniline from 1,2,3-trichlorobenzene which comprises the following sequential steps: (a) exchanging two chlorines from 1,2,3-trichlorobenzene with fluorines under conditions which give a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene; (b) selectively reducing the chlorine from the 2,3-difluorochlorobenzene in admixture with 2,6-difluorochlorobenzene by contacting the mixture with a hydrogen source in the presence of a palladium catalyst in an inert organic solvent from ambient temperature to about 150° C. to give a mixture of 2,6-difluorochlorobenzene and ortho-difluorobenzene; (c) aminating the mixture of 2,6-difluorobenzene and ortho-difluorobenzene under conditions which give a mixture of 2,6-difluoroaniline and ortho-difluorobenzene; and (d) separating the ortho-difluorobenzene and the 2,6-difluoroaniline from the reaction mixture and from each other.
Claim 4
Dependent Claim
112 words
A process for preparing 2,6-difluoroaniline from 1,2,3-trichlorobenzene which comprises the following sequential steps: (a) exchanging two chlorines from 1,2,3-trichlorobenzene with fluorines under conditions which give a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene; (b) selectively reducing the chlorine from the 2,3-difluorochlorobenzene in admixture with 2,6-difluorochlorobenzene by contacting the mixture with a hydrogen source in the presence of a palladium catalyst in an inert organic solvent from ambient temperature to about 150° C. to give a mixture of 2,6-difluorochlorobenzene and ortho-difluorobenzene; (c) aminating the mixture of 2,6-difluorobenzene and ortho-difluorobenzene under conditions which give a mixture of 2,6-difluoroaniline and ortho-difluorobenzene; and (d) separating the ortho-difluorobenzene and the 2,6-difluoroaniline from the reaction mixture and from each other.
Claim 5
Dependent Claim
85 words
A process for preparing ortho-difluorobenzene from 1,2,3-trichlorobenzene which comprises the following sequential steps: (a) exchanging two chlorines from 1,2,3-trichlorobenzene with fluorines under conditions which give a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene; (b) selectively reducing the chlorine from the 2,3-difluorochlorobenzene in admixture with 2,6-difluorochlorobenzene by contacting the mixture with a hydrogen source in the presence of a palladium catalyst in an inert organic solvent from ambient temperature to about 150° C. to give a mixture of 2,6-difluorochlorobenzene and ortho-difluorobenzene; (c) separating the ortho-difluorobenzene from the 2,6-difluorochlorobenzene.
Claim 6
Dependent Claim
85 words
A process for preparing ortho-difluorobenzene from 1,2,3-trichlorobenzene which comprises the following sequential steps: (a) exchanging two chlorines from 1,2,3-trichlorobenzene with fluorines under conditions which give a mixture of 2,6-difluorochlorobenzene and 2,3-difluorochlorobenzene; (b) selectively reducing the chlorine from the 2,3-difluorochlorobenzene in admixture with 2,6-difluorochlorobenzene by contacting the mixture with a hydrogen source in the presence of a palladium catalyst in an inert organic solvent from ambient temperature to about 150° C. to give a mixture of 2,6-difluorochlorobenzene and ortho-difluorobenzene; (c) separating the ortho-difluorobenzene from the 2,6-difluorochlorobenzene.
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) | 1995-02-24 | 1995-08-26 | 1996-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-24 | 1999-08-26 | 2000-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-24 | 2003-08-26 | 2004-02-25 | $7700.00 | Window Closed / Lapsed |