Org. Synth. 1951, 31, 29
DOI: 10.15227/orgsyn.031.0029
4,4'-DIBROMOBIPHENYL
[Biphenyl, 4,4'-dibromo-]
Submitted by Robert E. Buckles and Norris G. Wheeler
1.
Checked by R. S. Schreiber, Wm. Bradley Reid, Jr., and Robert W. Jackson.
1. Procedure
In a 15-cm. evaporating dish is placed 15.4 g. (0.10 mole) of finely powdered biphenyl (Note 1). The dish is set on a porcelain rack in a 30-cm. desiccator with a 10-cm. evaporating dish under the rack containing 39 g. (12 ml., 0.24 mole) of bromine. The desiccator is closed, but a very small opening is provided for the escape of hydrogen bromide (Note 2). The biphenyl is left in contact with the bromine vapor for 8 hours (or overnight). The orange solid is then removed from the desiccator and allowed to stand in the air under a hood for at least 4 hours (Note 3). At this point, the product weighs about 30 g. and has a melting point in the neighborhood of 152°. The crude 4,4'-dibromobiphenyl is dissolved in 75 ml. of benzene, filtered, and cooled to 15°. The resulting crystals are filtered, giving a yield of 23.4–24.0 g. (75–77%) of 4,4'-dibromobiphenyl, m.p. 162–163° (Note 4).
2. Notes
1.
The checkers used
Eastman Kodak Company white label grade of biphenyl.
2.
If a vacuum desiccator is used, the stopcock can be opened slightly to allow for the escape of
hydrogen bromide.
3.
The standing period allows
hydrogen bromide and
bromine to escape from the crystals.
4.
4,4'-Dibromobibenzyl can be prepared in the same manner.
Eighteen grams (0.10 mole) of finely divided bibenzyl is left in contact with the vapor from
39 g. (12 ml., 0.24 mole) of bromine for 24 hours. The desiccator is put under an opaque cover to keep out light, which causes the formation of
α,α'-dibromobibenzyl. The somewhat sticky reaction product is allowed to stand overnight. The crude product is dissolved in
300 ml. of isopropyl alcohol, filtered, and cooled. A yield of
15.0–17.0 g. (
44–50%) of
4,4'-dibromobibenzyl, m.p.
113–114°, is obtained.
3. Discussion
This method is a modification of that of Buckles, Hausman, and Wheeler.
2 4,4'-Dibromobiphenyl has also been prepared by the bromination of
biphenyl in water,
3 carbon disulfide,
4 and
glacial acetic acid;
5 by the bromination of a mixture of biphenylsulfonic acids in dilute
sulfuric acid;
6 by the action of
sodium carbonate7 or
ethanol8 on the perbromide obtained from the reaction of diazotized
benzidine with
bromine water; and by passing
p-dibromobenzene vapor through a red-hot tube.
94,4'-Dibromobibenzyl has been prepared by the bromination of
bibenzyl in water;
10 by the reaction of
p-bromobenzyl bromide with
zinc dust in water;
11 and by the reaction of
bromobenzene with
ethylene oxide in the presence of anhydrous
aluminum chloride.
12
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
bromine water
ethanol (64-17-5)
sulfuric acid (7664-93-9)
acetic acid (64-19-7)
Benzene (71-43-2)
hydrogen bromide (10035-10-6)
sodium carbonate (497-19-8)
bromine (7726-95-6)
aluminum chloride (3495-54-3)
zinc (7440-66-6)
isopropyl alcohol (67-63-0)
bromobenzene (108-86-1)
carbon disulfide (75-15-0)
Biphenyl (92-52-4)
Ethylene oxide (75-21-8)
benzidine (92-87-5)
α,α'-dibromobibenzyl (5789-30-0)
bibenzyl (103-29-7)
p-dibromobenzene (106-37-6)
4,4'-DIBROMOBIPHENYL,
Biphenyl, 4,4'-dibromo- (92-86-4)
p-bromobenzyl bromide (589-15-1)
4,4'-Dibromobibenzyl (19829-56-2)
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