Styrene dibromide

Dibromide formation. Dissolve 0 2 ml. of styrene in 0 5 ml. of CCI4 in a test-tube. Add slowly, drop by drop, a 10% solution of bromine in CCI4. Note the decolorisation of the bromine and absence of HBr fumes (therefore reaction by addition and not by substitution). Continue to add the bromine solution until a faint brown colour persists. Scratch the sides of the tube and cool it in ice-water. Filter off the crystals that separate and recrystallise the styrene dibromide from methanol m.p. 72 . 

Phenylacetylene is readily prepared by the dehydrohalogenatlon of styrene dibromide with a solution of sodamide in liquid ammonia ... 

GA UTION. Styrene dibromide is a skin irritant and all contact with It should be avoided. Rubber gloves should be used in its preparation. 

Stirrer, for caustic fusion, 30, 104, 105 seal for, 30, 54 Stobbe condensation, 30, 18 Styrene, 33, 72 Styrene dibromide, 30, 73 Styrene oxide, 31, 3 Succinic acid, cc-benzhydrylidene-,... 

By starting with styrene dibromide, the yield of phenyl acetylene is reduced to about 64%. 

Phenylacetylene has been prepared by the elimination of carbon dioxide from pbenylpropiolic acid by means of phenol1 or aniline 2 or by heating with barium hydroxide 3 from styrene dibromide, by heating with potassium hydroxide in alcohol 4 by heating /3-bromo or chloro styrene with sodium ethylate or potassium hydroxide in alcohol 5 by passing the vapors of a-dichloroethylbenzene over hot soda lime 6 by the action of alcoholic potassium hydroxide on dibenzal-acetone tetra-... 

Caution Avoid contact with styrene dibromide, which is a skin irritant. This preparation should be conducted in a hood to avoid exposure to ammonia. 

The styrene dibromide must not be added too rapidly, or the heat of reaction may cause rapid boiling of the ammonia and possible loss of part of the mixture. 

The stopper carrying the iron wire is removed, 2 g. of aniline is added, and then 528 g. (2 moles) of finely powdered, dry styrene dibromide is added gradually with vigorous stirring. The addition requires about 1 hour (Note 4). Stirring is continued for 2 hours (Note 5) after the addition is completed, after which 600 ml. of concentrated ammonium hydroxide is added, followed by 1 1. of distilled water, and the mixture is allowed to stand until the frost on the outside of the flask is entirely melted. 

Styrene, 1015, 1024 Styrene dibromide, 896, 900 Styrene oxide, 893, 894 Suberic acid, 893, 894 Sublimation, 37... 

Stearyl bromide, b319 Styrene dibromide, d79 Styrene glycol, pill Styrene oxide, e9 Suberic acid, o24 Suberonitrile, d239 Succinic acid monoamide, sl2 Succinonitrile, b380... 

Phenylacetylene has been prepared by treatment of /9-bromo-styrene with potassium hydroxide3 and with sodium amide in liquid ammonia,4 and from styrene dibromide by treatment with sodium amide in liquid ammonia.6... 

By the action of a solution of sodium in liquid anunonia, upon j3-bromostyrene or styrene dibromide. Vaughn, ibid. 56 2069 (1934). 

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