Organic Syntheses, Coll. Vol. 4, p.881 (1963); Vol. 36, p.86 (1956).
A 2-l. three-necked flask
is fitted with a reflux condenser (Note 1)
, a stirrer (Note 2)
, and a dropping funnel
. The flask is suspended in a steam cone
, which can also be used as a cooling bath
. In the flask is placed 50 g. (2.05 g. atoms) of fine magnesium turnings (Note 3)
. In the dropping funnel is first introduced 5 ml. of a solution of 250 g. (175 ml., 2.3 moles) of ethyl bromide
in 500 ml. of absolute ether
. Three drops of bromine
is mixed with the 5 ml., and the mixture is added to the magnesium
. The Grignard reaction which starts at once (Note 4)
is maintained by gradually adding the remainder of the ethyl bromide-ether
solution. When the spontaneous reaction subsides, the mixture is heated gently under reflux with stirring for 30 minutes.
The flask is then cooled in ice, and in the course of about 20 minutes 83 g. of tin tetrachloride (37 ml., 0.32 mole)
is added with vigorous stirring (Note 5)
. The mixture is heated at the reflux temperature for 1 hour, after which the condenser is set for distillation. During 1.5 hours the ether
is removed by distillation while the flask is heated by an ample supply of steam (Note 6)
and (Note 7)
The flask is again cooled in ice, the collected ether
is returned to the reaction mixture, and the latter is decomposed by slowly adding first 85 ml. of ice water, then 400 ml. of ice-cold 10% hydrochloric acid
. After stirring for some minutes, the contents of the flask are transferred to a separatory funnel
. The layers are separated, and the ether
layer is filtered through a folded filter and dried with calcium chloride (Note 8)
is removed by distillation, and the crude tetraethyltin
is distilled under water-pump vacuum, using a water bath
for heating. The yield of tetraethyltin
boiling at 63–65° /12 mm.
is 67–72 g.
1.1916 (Note 9)
A wide condenser must be employed to permit an ample reflux of ether
The submitters have carried out this preparation on a three-fold scale with comparable yields.
In general bromine
starts Grignard reactions more quickly than the usually employed iodine
For adding the tin tetrachloride
it is advisable to use a dropping funnel which contains no ether
vapor, since the latter gives troublesome formation of solid etherate.
The stirrer must be stopped at the beginning of the distillation or it will break, for the contents of the flask turn into a solid mass.
Removal of the ether
is necessary to permit raising the reaction temperature. The temperature at the center of the mass reaches 60–65°. During the 1.5 hours of distillation, about 200 ml. of ether
is collected, the remainder being firmly bound as etherates.
To obtain a product free from traces of triethyltin halide the dried ethereal solution is treated with dry ammonia
, and the precipitate formed is removed by filtration.
The submitters report that the same yields in terms of percentages are obtained if the procedure is applied to the preparation of tetra-n-propyltin
This preparation is referenced from:
Copyright © 1921-, Organic Syntheses, Inc. All Rights Reserved