US4158675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of halogenated compounds
Assignee: Imperial Chemical Industries Ltd
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Filing: 1978-02-07
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Granted: 1979-06-19
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Expires: 1998-02-07
Abstract
Abstract Manufacture of 1,1,1,2-tetrafluoroethane by reacting 1,1,1-trifluoro-2-chloroethane with hydrogen fluoride in the presence of a chromium oxide catalyst and removing 1,1-difluoro-2-chloroethylene contaminant from the resulting impure asym tetrafluoroethane product by passing the impure product with hydrogen fluoride over a chromium oxide catalyst at much lower temperatures than are used in the manufacturing process.
Inventors
- 👤 Stephen E. Potter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:09
CPC Classifications
C; C07; C07C; C07C19/00; C07C19/08; C07C17/00; C07C17/093; C07C17/20; C07C17/202; C07C17/206; C07C17/38; C07C17/395
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
111 words
A process for the manufacture of 1,1,1,2-tetrafluoroethane which comprises reacting in the vapour phase at elevated temperature a haloethane of formula CX 3 CH 2 Y wherein X is bromine, chlorine or fluorine and Y is chlorine with hydrogen fluoride in the presence of a catalyst which is chromium oxide or which is at least in part basic chromium fluoride and wherein the 1,1,1,2-tetrafluoroethane product containing 1,1-difluoro-2-chloroethylene as impurity is brought together with hydrogen fluoride into contact with said catalyst which is chromium oxide or which is at least in part basic chromium fluoride at a temperature in the range 100° C. to 275° C. whereby said haloethylene content is reduced.
Claim 2
Dependent Claim
111 words
A process for the manufacture of 1,1,1,2-tetrafluoroethane which comprises reacting in the vapour phase at elevated temperature a haloethane of formula CX 3 CH 2 Y wherein X is bromine, chlorine or fluorine and Y is chlorine with hydrogen fluoride in the presence of a catalyst which is chromium oxide or which is at least in part basic chromium fluoride and wherein the 1,1,1,2-tetrafluoroethane product containing 1,1-difluoro-2-chloroethylene as impurity is brought together with hydrogen fluoride into contact with said catalyst which is chromium oxide or which is at least in part basic chromium fluoride at a temperature in the range 100° C. to 275° C. whereby said haloethylene content is reduced.
Claim 3
Dependent Claim
19 words
A process as claimed in claim 1 in which in the haloethane starting material X is chlorine and/or fluorine.
Claim 4
Dependent Claim
18 words
A process as claimed in claim 2 in which at least one of the X substituents is fluorine.
Claim 5
Dependent Claim
13 words
A process as claimed in claim 3 in which the haloethane is 1,1,1-trifluoro-2-chloroethane.
Claim 6
Dependent Claim
66 words
A process as claimed in any of the preceding claims wherein a chromium oxide catalyst is employed in the manufacture and purification process which is obtained by treating a chromium hydroxide paste in an atmosphere comprising 10 to 100 molar percent by weight of steam at a temperature of 50° C. to 180° C. for at least one hour and subsequently drying and calcining the product.
Claim 7
Dependent Claim
39 words
A process as claimed in claim 1 wherein the organic starting material is 1,1,1-trifluoro-2-chloroethane and in which the resulting crude impure 1,1,1,2-tetrafluoroethane is associated with other haloethanes containing fluorine including one or more of pentafluoroethane, 1,1,1,2-tetrafluoro-2-chloroethane, 1,1,1-tetrafluoroethane and 1,1,1-trifluoro-2-chloroethane.
Claim 8
Dependent Claim
62 words
A process as claimed in claim 4 which the crude impure product comprising 1,1,1,2-tetrafluoroethane, said other haloethanes containing fluorine and unreacted hydrogen fluoride leaving the reactor are passed into a second reactor containing a catalyst which is chromium oxide or which is at least in part basic chromium fluoride and maintained at a temperature in the range 100° C. to 275° C.
Claim 9
Dependent Claim
97 words
A process as claimed in claim 4 carried out in a single reactor having a first reaction zone containing a catalyst which chromium oxide or at least in part basic chromium fluoride maintained at a temperature of 300° C. to 400° C. to produce said crude impure organic product comprising 1,1,1,2-tetrafluoroethane, other haloethanes and unreacted hydrogen fluoride which is fed to a second part of the reaction zone containing said chromium oxide or basic chromium fluoride catalyst maintained at a temperature in the range 100° C. to 275° C. whereby the amount of 1,1-difluoro-2-chloroethylene contaminant is reduced.
Claim 10
Dependent Claim
28 words
A process as claimed in claim 1 in which the purification of the asym-tetrafluoroethane is carried out at a temperature in the range 125° C. to 250° C.
Claim 11
Dependent Claim
57 words
A process for the reduction of 1,1-difluoro-2-chloroethylene impurity contained in 1,1,1,2-tetrafluoroethane which comprises treating the impure 1,1,1,2-tetrafluoroethane with hydrogen fluoride in the presence of a catalyst which is chromium oxide or which is at least in part basic chromium fluoride at temperatures in the range of 100° C. to 275° C. whereby said haloethylene content is reduced.
Claim 12
Dependent Claim
57 words
A process for the reduction of 1,1-difluoro-2-chloroethylene impurity contained in 1,1,1,2-tetrafluoroethane which comprises treating the impure 1,1,1,2-tetrafluoroethane with hydrogen fluoride in the presence of a catalyst which is chromium oxide or which is at least in part basic chromium fluoride at temperatures in the range of 100° C. to 275° C. whereby said haloethylene content is reduced.
References Cited (Backward Citations)
US2885427A
Cited
US3755477A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-06-18 | 1982-12-18 | 1983-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-06-18 | 1986-12-18 | 1987-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-06-18 | 1990-12-18 | 1991-06-19 | $7700.00 | Window Closed / Lapsed |