In a
2-l. round-bottomed flask, fitted with a
liquid-sealed mechanical stirrer, a
gas inlet tube, and a
tube to carry off hydrogen chloride and acetic acid vapors (Note
1), are placed
915 cc. of glacial acetic acid,
327 g. (5 gram atoms) of zinc dust, and
352 g. (1 mole) of cetyl iodide (m.p.
20–22°)
(p. 322). The mixture is saturated with dry
hydrogen chloride and then stirred and heated on a
steam bath. At the end of every five hours of heating, the mixture is again saturated with
hydrogen chloride. After the reaction has proceeded for twenty-five hours, the mixture is allowed to cool, and the layer of
hexadecane, which rises to the top of the reaction mixture, is separated. The residue is poured into 3 l. of water and filtered on a
Büchner funnel to remove the
zinc dust. The
zinc dust is washed with 500 cc. of water and then with
250 cc. of ether. The combined water layers are extracted with two
500-cc. portions of ether. The
ether extracts are combined and added to the
hexadecane, and the resulting solution is washed with two
250-cc. portions of 20 per cent sodium hydroxide and then with water until free of alkali. The
ether solution is dried with
150 g. of anhydrous sodium sulfate, filtered, and distilled from a
500-cc. modified Claisen flask with a fractionating side arm. The yield of
n-hexadecane boiling at
156–158°/14 mm. and melting at
16–17° is
192 g. (
85 per cent of the theoretical amount).