US4937397A
Expired / Lapsed
US
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Preparation of halofluorobenzenes
Assignee: Dow Chemical Co
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Filing: 1988-11-28
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Granted: 1990-06-26
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Expires: 2008-11-28
Abstract
Abstract Chlorofluorobenzenes and difluorobenzenes are prepared by contacting a dichlorobenzene with an effective amount of KF or CsF in a polar aprotic solvent at an elevated temperature under substantially anhydrous conditions. The product can be removed as it is formed or the reaction may be run at the autogenous pressures generated by the reaction mixture in a sealed reactor.
Inventors
- 👤 R. Garth Pews
- 👤 James A. Gall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:06
CPC Classifications
C; C07; C07C; C07C17/00; C07C17/093; C07C17/20; C07C17/202; C07C17/208
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
74 words
A process for preparing a chlorofluorobenzene or difluorobenzene of the formula ##STR8## which comprises contacting a dihalobenzene of the formula ##STR9## wherein Y is F or Cl, with an effective amount of KF under substantially anhydrous conditions is a solvent selected from the group consisting of N-methyl pyrrolidinone, N-cyclohexyl pyrrolidinone, 1,3-dimethyl-2-imidazolidinone and 1,3-dimethyl-3,4,5,6-tetrahydro-2-(1H)pyrimidone at a temperature from about 290° to about 350° C., and recovering the chlorofluorobenzene or the difluorobenzene from the reaction mixture.
Claim 2
Dependent Claim
74 words
A process for preparing a chlorofluorobenzene or difluorobenzene of the formula ##STR8## which comprises contacting a dihalobenzene of the formula ##STR9## wherein Y is F or Cl, with an effective amount of KF under substantially anhydrous conditions is a solvent selected from the group consisting of N-methyl pyrrolidinone, N-cyclohexyl pyrrolidinone, 1,3-dimethyl-2-imidazolidinone and 1,3-dimethyl-3,4,5,6-tetrahydro-2-(1H)pyrimidone at a temperature from about 290° to about 350° C., and recovering the chlorofluorobenzene or the difluorobenzene from the reaction mixture.
Claim 3
Dependent Claim
10 words
The process of claim 1 in which Y is F.
Claim 4
Dependent Claim
14 words
The process of claim 2 in which Y is ortho to the exchanging Cl.
Claim 5
Dependent Claim
14 words
The process of claim 2 in which Y is meta to the exchanging Cl.
Claim 6
Dependent Claim
14 words
The process of claim 2 in which Y is para to the exchanging Cl.
Claim 7
Dependent Claim
10 words
The process of claim 1 in which Y is Cl.
Claim 8
Dependent Claim
14 words
The process of claim 6 in which Y is ortho to the exchanging chlorine.
Claim 9
Dependent Claim
14 words
The process of claim 6 in which Y is meta to the exchanging chlorine.
Claim 10
Dependent Claim
14 words
The process of claim 6 in which Y is para to the exchanging chlorine.
Claim 11
Dependent Claim
21 words
The process of claim 1 including the additional step of carrying out the reaction in the presence of a phase-transfer catalyst.
Claim 12
Dependent Claim
21 words
The process of claim 1 including the additional step of carrying out the reaction in the presence of an acid scavenger.
Claim 13
Dependent Claim
24 words
The process of claim 1 in which the reaction is run at the autogenous pressure generated by the reaction mixture in a scaled reactor.
Claim 14
Dependent Claim
64 words
A process for preparing o-chlorofluorobenzene which comprises contacting o-dichlorobenzene with from about 1.0 to about 4.0 molar equivalents of KF under substantially anhydrous conditions in a polar aprotic solvent selected from the group consisting of N-methyl pyrrolidinone, N-cyclohexyl pyrrolidinone, 1,3-dimethyl-2-imidazolidinone and 1,3-dimethyl-3,4,5,6-tetrahydro-2-(1H)pyrimidone at a temperature from about 290° to about 350° C. at an elevated pressure, and recovering the o-chlorofluorobenzene from the reaction medium.
Claim 15
Dependent Claim
64 words
A process for preparing o-chlorofluorobenzene which comprises contacting o-dichlorobenzene with from about 1.0 to about 4.0 molar equivalents of KF under substantially anhydrous conditions in a polar aprotic solvent selected from the group consisting of N-methyl pyrrolidinone, N-cyclohexyl pyrrolidinone, 1,3-dimethyl-2-imidazolidinone and 1,3-dimethyl-3,4,5,6-tetrahydro-2-(1H)pyrimidone at a temperature from about 290° to about 350° C. at an elevated pressure, and recovering the o-chlorofluorobenzene from the reaction medium.
Claim 16
Dependent Claim
22 words
The process of claim 13 in which the elevated pressure is from slightly above atmospheric to about 500 pounds per square inch.
Claim 17
Dependent Claim
23 words
The process of claim 13 in which the elevated pressure is the autogenous pressure generated by the reaction mixture in a sealed reactor.
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) | 1993-06-25 | 1993-12-25 | 1994-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-25 | 1997-12-25 | 1998-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-25 | 2001-12-25 | 2002-06-26 | $7700.00 | Window Closed / Lapsed |