Claims
- 1. A continuous non-catalytic process for the manufacture of a mixture of 1,1-dichloro-1-fluoroethane and 1-chloro-1,1-difluoroethane from 1,1,1-trichloroethane comprising:
- (a) continuously feeding hydrogen fluoride and 1,1,1-trichloroethane in a selected molar feed ratio to a reaction zone containing HF to form a liquid phase hydrofluorination reaction mixture in said reaction zone which reaction mixture contains a large molar excess of HF relative to 1,1,1-trichloroethane;
- (b) continuously withdrawing from the reaction zone, vapor phase reaction product comprising 1,1-dichloro-1-fluoroethane and 1-chloro-1,1-difluoroethane;
- (c) continuously refluxing hydrogen fluoride from the vapor phase reaction product to the reaction mixture to maintain a large molar excess of HF relative to 1,1,1-trichloroethane in the reaction mixture sufficient to prevent substantial precipitation of 1,1,1-trichloroethane from the reaction mixture"has been added after mixture"; and
- (d) obtaining a mixture of 1,1-dichloro-1-fluoroethane and 1-chloro-1,1-difluoroethane from the vapor phase reaction product;
- wherein said selected hydrogen fluoride/1,1,1-trichloroethane molar feed ratio
- (i) is within the range of from about 3.0 to about 5.2; and
- (ii) is greater than the value M determined by the equation
- M=2.7X+4.2Y
- wherein
- X is the desired mole fraction of 1-chloro-l,1-difluoroethane in the resulting 1,1-dichloro-1-fluoroethane/1-chloro-1,1-difluoroethane mixture; and
- Y is the desired mole fraction of 1,1-dichloro-1-fluoroethane in the resulting 1,1-dichloro-1-fluoroethane-/1-chloro-1,1-difluoroethane mixture.
- 2. A process according to claim 1 wherein the reflux ratio is about 1:1, by weight.
- 3. A process according to claim 1 wherein the vapor phase reaction product is withdrawn at a constant rate equal to the sum of the rates at which hydrogen fluoride and 1,1,1-trichloroethane are fed into the reaction zone.
- 4. A process according to claim 1 wherein the vapor phase reaction product contains no more than about 0.5 wt. % 1,1,1-trifluoroethane.
- 5. A process according to claim 1 wherein the mixture of 1,1-dichloro-1-fluoroethane and 1-chloro-1,1-difluoroethane obtained comprises from about 50 wt. % to about 85 wt. % 1,1-dichloro-1-fluoroethane.
- 6. A process according to claim 5 wherein the mixture comprises from about 75 wt. % to about 85 wt. % 1,1-dichloro-1-fluoroethane.
Parent Case Info
This is a continuation of application Ser. No. 07/561,212 filed on Jul. 30, 1990 now abandoned which is a continuation of application Ser. No. 365,345 filed on Jun. 13, 1989 now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
2058453 |
Holt et al. |
Oct 1936 |
|
2450414 |
Benning |
Oct 1948 |
|
3833676 |
Ukaji et al. |
Sep 1974 |
|
Non-Patent Literature Citations (1)
Entry |
Chem. Abstracts 85:123323v (1976). |
Continuations (2)
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Number |
Date |
Country |
Parent |
561212 |
Jul 1990 |
|
Parent |
365345 |
Jun 1989 |
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