40, Fig. 3) which gives the same effect as a fractionating column.
The material is collected from 135-140'0/38 mm. (115-120'0/10 mm.).
The yield is 740-830 g. (80-90 per cent of the theoretical amount).

[1] J. Am. Chem. Soc. 39, 2718 (1917). 2. Notes

The quality of the benzyl chloride markedly affects the yield
of pure benzyl cyanide. If a poor technical grade is used,
the yields will not be more than 60-75 per cent of the theoretical,
whereas consistent results of about 85 per cent or more were always
obtained when a product was used that boiled over 10'0. The technical
benzyl chloride at hand yielded on distillation about 8 per cent
of high-boiling material; a technical grade from another source was
of unusual purity and boiled over a 2'0 range for the most part.

It is advisable to distil off the last portion of alcohol and water
_in vacuo_ and also to distil the benzyl cyanide _in vacuo_,
since under ordinary pressures a white solid invariably separates
during the distillation.

One method of purifying the benzyl cyanide is to steam distil it
after the alcohol has been first distilled from the reaction mixture.
At ordinary pressures, this steam distillation is very slow and,
with an ordinary condenser, requires eighteen to twenty hours
in order to remove all of the volatile product from a run of 500 g.
of benzyl chloride. The distillate separates into two layers; the benzyl
cyanide layer is removed and distilled. The product obtained in this
way is very pure and contains no tarry material, and, after the excess
of benzyl chloride has been removed, boils practically constant.
This steam distillation is hardly advisable in the laboratory.