Org. Synth. 1921, 1, 35
DOI: 10.15227/orgsyn.001.0035
α-BROMONAPHTHALENE
[Naphthalene, 1-bromo-]
Submitted by H. T. Clarke and M. R. Brethen.
Checked by J. B. Conant and G. W. Wheland.
1. Procedure
In a
2-l. flask are placed
512 g. (4 moles) of naphthalene and
275 g. (170 cc.) of carbon tetrachloride. The flask is equipped with a stirrer, an
efficient reflux condenser, and a
dropping funnel, the stem of which extends below the level of the liquid. From the top of the reflux condenser a tube leads to a
water trap similar to that described in
Fig. 7 on p. 97. The mixture is warmed on a
steam bath to gentle boiling, and
707 g. (220 cc., 4.4 moles) of bromine is run in at such a rate that practically none of it is carried over with the
hydrogen bromide into the trap. This requires from twelve to fifteen hours, during which time the mixture is gently warmed on the steam bath, with continual stirring, until the evolution of
hydrogen bromide ceases (about six hours). The mixture is now distilled from the steam bath under slightly reduced pressure (using a condenser) until free of
carbon tetrachloride; the residue is mixed with
20–30 g. of powdered or granulated sodium hydroxide and stirred at 90–100° for four hours
(Note 1). The liquid is transferred to a flask for fractional distillation and distilled under reduced pressure. The forerun contains a considerable proportion of unchanged
naphthalene, the bulk of which is removed by chilling and filtering with suction; the main fraction,
consisting of
bromonaphthalene, passes over at
132–135°/12 mm. (
145–148°/20 mm.), and a high-boiling fraction, consisting of
dibromonaphthalene, is collected. The intermediate fractions and the filtrates from the foreruns are systematically redistilled; in this way
600–620 g. of colorless
α-bromonaphthalene (
72–75 per cent of the theoretical amount) and about
30 g. of a mixture of dibromonaphthalenes (m.p., about
60°) are obtained.
2. Notes
1.
If this treatment with
sodium hydroxide is omitted, the final product contains impurities which gradually give off
hydrogen bromide.
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3. Discussion
α-Bromonaphthalene can be prepared by the action of
bromine upon
naphthalene without a solvent
1 and in
carbon disulfide;
2 by treating a suspension of
naphthalene in a solution of
bromine in
alkali with hydrochloric acid;
3 and by treating a suspension of
naphthalene in warm water with
bromine.
4 The procedure described has been found to be more convenient and to give considerably better yields than that reported previously.
4 An essentially similar procedure has been described.
5 The method in which a suspension of
naphthalene in alkaline
hypobromite solution is treated with
hydrochloric acid in aqueous solution
3 was found to give a satisfactory yield, but it presented considerable difficulties in the recovery of the
hydrobromic acid.
Iodine monobromide has been used successfully to brominate
naphthalene.
6
This preparation is referenced from:
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
mixture of dibromonaphthalenes
hydrochloric acid (7647-01-0)
sodium hydroxide (1310-73-2)
HYDROBROMIC ACID,
hydrogen bromide (10035-10-6)
bromine (7726-95-6)
carbon tetrachloride (56-23-5)
carbon disulfide (75-15-0)
α-Bromonaphthalene,
bromonaphthalene (90-11-9)
Naphthalene, 2-bromo- (580-13-2)
Naphthalene (91-20-3)
dibromonaphthalene
hypobromite
Iodine monobromide (7789-33-5)
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