Organic Syntheses, CV 1, 156
Submitted by Charles F. H. Allen
Checked by C. S. Marvel and C. G. Gauerke.
1. Procedure
In a
2-l. three-necked, round-bottomed flask, fitted with a
stirrer, a
reflux condenser and a
separatory funnel are placed
82 g. (1.2 moles) of potassium cyanide (95 per cent) (Note
1) and 100 cc. of water. The mixture is warmed and stirred until the
cyanide is completely dissolved. To this solution is added
350 cc. of 95 per cent alcohol, followed by
158 g. (1 mole) of trimethylene chlorobromide (Note
2), and the mixture is heated under a reflux condenser (best on a
water bath) with stirring for about one and one-half hours.
The solution is cooled and then diluted with 450 cc. of water. The oily layer of
chloronitrile is collected in about
80 cc. of chloroform and separated from the water solution. The
chloroform solution is washed with about
125–150 cc. of calcium chloride solution (prepared by adding one volume of water to an equal volume of a saturated solution of crystallized
calcium chloride) and once with 125–150 cc. of water, and then dried over fused
calcium chloride.
The dried solution is then fractionally distilled in a
modified 100-cc. Claisen flask (p. 130). The
chloroform is removed by distilling at ordinary pressure until the temperature reaches 120° (Note
3). The remainder may be fractionated under ordinary pressure but it is better to use reduced pressure. After two or three distillations the yield of pure product boiling at
93–96°/26 mm. (Note
4) and (Note
5) is
42–49 g. (
60–70 per cent of the theoretical amount based on the chlorobromide used, or
40–47 per cent based on the total amount of chlorobromide taken) (Note
5) and (Note
6).
2. Notes
1. An equivalent amount
(58 g., 1.2 moles) of sodium cyanide dissolved in 90 cc. of water may be used instead of the
potassium salt without materially altering the yields.
3. The
chloroform fraction has a very strong odor of
isonitrile. Only a trace is noted in the redistilled product.
4. When the distillation is carried out under ordinary pressures (about 745 mm.) the product boils at
194–197°.
5. The lower-boiling fraction is mainly unchanged
trimethylene chlorobromide and amounts to
15–20 g. It may be refractionated or used directly in a subsequent run. The high-boiling residue is mainly
trimethylene cyanide. If the residues from several runs are combined and redistilled, an average of
6–7 g. per run of product boiling at
160–165°/26 mm. is obtained.
3. Discussion
This preparation is referenced from:
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