In a
2-l. round-bottomed, three-necked flask fitted with a
mercury-sealed mechanical stirrer, a
reflux condenser, and a
separatory funnel is placed
40 g. (1.65 atoms) of magnesium turnings (Note
1). This is covered with
200 cc. of dry ether, and there is then added
100 cc. of a mixture of 260 g. (1.65 moles) of dry bromobenzene and 800 cc. of dry ether. As soon as the reaction starts,
200 cc. more of dry ether is added and the remainder of the
bromobenzene solution at such a rate as to cause gentle boiling (about two hours). With external cooling, the time may be shortened.
When all the
bromobenzene has been added, there is added slowly through the separatory funnel a solution of
114 g. (0.5 mole) of freshly distilled antimony trichloride (m.p.
67–73°) in
300 cc. of dry ether. The reaction proceeds smoothly and even briskly with the freshly distilled chloride. However, if the latter has not been freshly prepared, gentle warming may be required to start the reaction. When all the
antimony trichloride has been added (one to two hours), the mixture is heated on the
steam bath for one hour longer.
When cool, the reaction mixture is poured slowly with stirring into 1 l. of ice and water (Note
2). If the stirring is thorough, most of the
triphenylstibine is to be found in the ether layer. The hydrolysis mixture is filtered through a
Büchner funnel and the residue on the
filter extracted three times (Note
3) with
100-cc. portions of ether. The aqueous layer is separated and extracted twice with
200-cc. portions of ether. The combined ether portions are evaporated slowly on a steam bath to remove the ether, and there remains behind a yellow semi-solid which crystallizes to a white solid on cooling (Note
4). The yield of crude product melting at
49° is
145–160 g. (
82–90 per cent of the theoretical amount). For purification from a small amount of
biphenyl which is present in the crude product,
90 g. of
triphenylstibine is dissolved in
200 cc. of petroleum ether (b.p.
40–50°) by warming on a steam bath. There is generally a small amount of insoluble residue which is filtered and the filtrate cooled in a freezing mixture. The
triphenylstibine separates as small prisms and weighs
58–65 g.; by further concentration of the filtrate to an approximate volume of 50 cc. and then cooling again, an additional
15–20 g. of product separates. Both portions melt at
50°.