US4794200A
Expired / Lapsed
US
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Process for the preparation of trifluoromethyl iodide
Assignee: Rhodia Chimie SAS
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Filing: 1987-10-09
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Granted: 1988-12-27
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Expires: 2007-10-09
Abstract
Abstract A process for the preparation of trifluoromethyl iodide by bringing into contact with one another to form a reaction product either: zinc, sulfur dioxide, and trifluoromethyl bromide, or (b) sodium dithionite and trifluoromethyl bromide; in a polar aprotic solvent, such as dimethylformamide, preferably followed by a filtration stage to remove the solid products. Thereafter, iodine dissolved in carboxylic or sulfuric acid is added to the reaction product, and trifluoromethyl iodide is evolved.
Inventors
- 👤 Marc Tordeux
- 👤 Claude Wakselman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:11
CPC Classifications
C; C07; C07C; C07C17/00; C07C17/093; C07C17/20; C07C17/202; C07C17/204
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
97 words
A process for the preparation of trifluoromethyl iodide which comprises the steps of, in a first stage, introducing into a polar aprotic solvent either a metal selected from the group consisting of zinc, cadmium, aluminum and manganese, together with sulfur dioxide, or an alkali metal dithionite; thereafter adding thereto trifluoromethyl bromide at a pressure greater than one bar for a time sufficient to react; and, in a second stage, adding iodine dissolved in a carboxylic or sulfonic acid to the reaction product of the first stage and reacting for a time sufficient to obtain said trifluoromethyl iodide.
Claim 2
Dependent Claim
97 words
A process for the preparation of trifluoromethyl iodide which comprises the steps of, in a first stage, introducing into a polar aprotic solvent either a metal selected from the group consisting of zinc, cadmium, aluminum and manganese, together with sulfur dioxide, or an alkali metal dithionite; thereafter adding thereto trifluoromethyl bromide at a pressure greater than one bar for a time sufficient to react; and, in a second stage, adding iodine dissolved in a carboxylic or sulfonic acid to the reaction product of the first stage and reacting for a time sufficient to obtain said trifluoromethyl iodide.
Claim 3
Dependent Claim
10 words
The process of claim 1, wherein said metal is zinc.
Claim 4
Dependent Claim
12 words
The process of claim 1, wherein said polar aprotic solvent is dimethylformamide.
Claim 5
Dependent Claim
13 words
The process of claim 1, wherein said alkali metal dithionite is sodium dithionite.
Claim 6
Dependent Claim
12 words
The process of claim 1, wherein said carboxylic acid is acetic acid.
Claim 7
Dependent Claim
13 words
The process of claim 1, wherein said carboxylic or sulfonic acid is perfluorinated.
Claim 8
Dependent Claim
26 words
The process of claim 1, wherein the ratio of moles of said trifluoromethyl bromide to gram-atoms of said metal is greater than or equal to 2:1.
Claim 9
Dependent Claim
24 words
The process of claim 1, wherein the ratio of moles of said sulfur dioxide to gram-atoms of said metal ranges from 1:1 to 3:1.
Claim 10
Dependent Claim
20 words
The process of claim 1, wherein 0.25 to 1 gram-atoms of said metal are employed per liter of said solvent.
Claim 11
Dependent Claim
30 words
The process of claim 1, wherein either said dithionite or said combination of metal and sulfur dioxide is employed in the presence of a base or a weakly acidic salt.
Claim 12
Dependent Claim
13 words
The process of claim 10, wherein said weakly acidic salt is disodium phosphate.
Claim 13
Dependent Claim
19 words
The process of claim 1, wherein said dithionite is introduced as a saturated solution in water or in formamide.
Claim 14
Dependent Claim
29 words
The process of claim 1, wherein the ratio of moles of said iodine to gram-atoms of said metal or to moles of said dithionite ranges from 0.5:1 to 2:1.
Claim 15
Dependent Claim
20 words
The process of claim 1, wherein said reaction pressure employed in said first stage ranges from 1 to 50 bar.
Claim 16
Dependent Claim
20 words
The process of claim 1, wherein the reaction temperature employed in said first stage ranges from 45° to 85° C.
Claim 17
Dependent Claim
20 words
The process of claim 15, wherein said reaction temperature employed in said first stage ranges from 65° to 75° C.
Claim 18
Dependent Claim
19 words
The process of claim 1, wherein the temperature employed in said second stage ranges from 100° to 140° C.
Claim 19
Dependent Claim
21 words
The process of claim 1, wherein solids formed in said first stage are removed by filtation prior to said second stage.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |