Org. Synth. 1954, 34, 16
DOI: 10.15227/orgsyn.034.0016
2-CHLORO-1,1,2-TRIFLUOROETHYL ETHYL ETHER
[Ether, 2-chloro-1,1,2-trifluoroethyl ethyl]
Submitted by Bruce Englund
1
Checked by R. S. Schreiber and Burris D. Tiffany.
1. Procedure
The apparatus used is shown in
Fig. 6 (Note 1). A solution of
sodium ethoxide prepared by dissolving 2.5 g. (0.11 g. atom) of clean sodium in 230 g. (292 ml., 5 moles) of absolute ethanol under anhydrous conditions is added to the
reaction tube C. Tube
C thus charged is weighed and placed in position with the
gas inlet tube, fitted with fritted-glass dispersion cylinder D, extending nearly to the bottom. Several inches of
ethanol is placed in tube
G, which serves as a flow indicator. The traps
A and
F are provided to protect against suck-back if the gas flow is interrupted. The seal at
B is a sleeve of rubber tubing. Any
efficient reflux condenser E is satisfactory.
Fig. 6.
Chlorotrifluoroethylene (Note 2) is introduced at such a rate, controlled by the needle valve, that it is essentially all absorbed in the reaction tube C, as indicated by the escape of little or no gas through tube G. At this rate, 233 g. (2 moles) (Note 3) is absorbed in 2–2.5 hours, during which the temperature rises to the point of reflux (Note 4).
When the required amount of
chlorotrifluoroethylene has been absorbed, the reaction mixture is poured into 500 ml. of water. The product separates as a light-yellow oil, which is separated, washed with 250 ml. of water, and dried over
20 g. of anhydrous calcium chloride. From
233 g. of chlorotrifluoroethylene (2 moles), the yield of crude product is
300–315 g. (
92–97%). This material is suitable for use in preparation of
ethyl chlorofluoroacetate (p. 423). It may be fractionated through an
efficent column to give
285–300 g. (
88–92%) of pure
chlorotrifluoroethyl ethyl ether, b.p.
87–88°,
n25D 1.3427.
2. Notes
1.
The reaction tube
C may be of any convenient size. The tube used by the submitter was 300 by 55 mm., fitted with a 55/35 standard taper ground-glass joint. The checkers used a
500-ml. calibrated dropping funnel which was convenient for following the increase in volume during the absorption of the
chlorotrifluoroethylene. For safety, a
heavy grease such as Cello-Grease was used in the stopcock.
2.
The
chlorotrifluoroethylene used was inhibited polymerization grade, supplied by the Kinetic Chemicals Division, Organic Chemicals Department, E. I. du Pont de Nemours and Company, Wilmington, Delaware.
3.
The amount of
chlorotrifluoroethylene absorbed is determined by weighing the reaction tube
C and contents. A convenient alterntive is to note the increase in volume of the reaction mixture, which in this case amounts to 165 ml.
4.
The rate of absorption is slow at first but increases as the temperature rises.
3. Discussion
2-Chloro-1,1,2-trifluoroethyl ethyl ether has been prepared by the base-catalyzed addition of
ethanol to
1-chloro-1,2,2-trifluoroethylene.
2,3,4
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
ethanol (64-17-5)
calcium chloride (10043-52-4)
sodium (13966-32-0)
sodium ethoxide (141-52-6)
chlorotrifluoroethyl ethyl ether,
2-Chloro-1,1,2-trifluoroethyl ethyl ether,
Ether, 2-chloro-1,1,2-trifluoroethyl ethyl (310-71-4)
Chlorotrifluoroethylene,
1-chloro-1,2,2-trifluoroethylene (79-38-9)
ethyl chlorofluoroacetate (401-56-9)
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