Org. Synth. 1929, 9, 72
DOI: 10.15227/orgsyn.009.0072
γ-PHENOXYPROPYL BROMIDE
[Propane, 1-bromo-2-phenoxy-]
Submitted by C. S. Marvel and A. L. Tanenbaum.
Checked by H. T. Clarke and C. J. Malm.
1. Procedure
In a
5-l. round-bottomed flask, fitted with a stopper carrying a
long reflux condenser, a
mechanical stirrer (Note 1), and a
separatory funnel, are placed 2 l. of water
(Note 2),
1 kg. (4.95 moles) of trimethylene bromide (p. 30) (Note 3), and
370 g. (3.9 moles) of phenol. The stirrer is started, and the mixture is heated to boiling. To the boiling solution is added a solution of
150 g. (3.75 moles) of sodium hydroxide in 500 cc. of water at such a rate that all is added in about one hour. The mixture is refluxed for five to six hours longer to complete the reaction, then cooled, and the upper water layer is separated and discarded.
The lower layer consists of
trimethylene bromide,
phenoxypropyl bromide, and
diphenoxypropane. This mixture is distilled under reduced pressure, a
Claisen flask with a modified side arm
(p. 130) being used. The first fraction is collected up to 136°/20 mm.; it consists of water and recovered
trimethylene bromide with a little
phenoxypropyl bromide (Note 4). The water is separated and discarded. The recovered
trimethylene bromide weighs
340–450 g. (Note 5). The next fraction is pure
phenoxypropyl bromide, which boils at
136–142°/20 mm. The yield is
495–600 g. (
84–85 per cent of the theoretical amount based on the
trimethylene bromide not recovered)
(Note 6). On cooling, the
phenoxypropyl bromide crystallizes to a white solid, m.p.
7–8°. A small amount (
50–80 g.) of
diphenoxypropane is left as a residue in the distilling flask.
2. Notes
1.
The reaction may be run without stirring, but a longer period of refluxing is necessary and the yield is lower.
2.
If less water is used in the reaction mixture,
sodium bromide separates.
3.
The large excess of
trimethylene bromide must be used in order to avoid the formation of large amounts of
diphenoxypropane.
4.
Phenoxypropyl bromide attacks
rubber stoppers quite readily, and the side arm of the distillation flask should be set in
(p. 130), in order to avoid contamination of the distillate.
5.
The use of recovered
trimethylene bromide does not result in so good a yield of
phenoxypropyl bromide, because a little
phenoxypropyl bromide is already present and during the reaction is converted to
diphenoxypropane.
6.
Phenoxyethyl bromide may be made in a similar manner.
Two kilos (10.7 moles) of ethylene bromide,
785 g. (8.5 moles) of phenol, and 2 l. of water, upon treatment with
375 g. (9.4 moles) of sodium hydroxide, yield
960–970 g. of
phenoxyethyl bromide (
55–56 per cent of the theoretical amount) boiling at
125–130° /18 mm.
3. Discussion
γ-Phenoxypropyl bromide can be prepared by the action of
sodium phenoxide on
trimethylene bromide in
alcohol solution.
1 The procedure described has been published.
2
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
alcohol (64-17-5)
sodium hydroxide (1310-73-2)
phenol (108-95-2)
sodium bromide (7647-15-6)
Trimethylene bromide (109-64-8)
ethylene bromide (106-93-4)
sodium phenoxide
γ-Phenoxypropyl bromide,
phenoxypropyl bromide (588-63-6)
Propane, 1-bromo-2-phenoxy-
diphenoxypropane
Phenoxyethyl bromide (589-10-6)
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