In a
5-l. flask (Note
1) provided with a
mechanical stirrer, a
reflux condenser, and a
hopper which can be opened or closed at the bottom by means of a
rubber bung attached to a
glass rod (Fig. 12),
Fig. 12.
 |
are placed
3 l. of anhydrous ether and
1290 g. (943 cc., 10 moles) of glycerol α,γ-dichlorohydrin (p. 292). The flask is surrounded by a
cold-water bath, and
440 g. (11 moles) of finely powdered sodium hydroxide (Note
2), which has been passed through a
20-mesh sieve, is added through the hopper in small portions, with continual stirring, while the temperature is kept at 25–30°. The addition requires about twenty minutes. The cold water is replaced by water at 40–45°, and the mixture boiled gently with stirring for four hours. It is necessary to cool the
vessel at least once every hour during this period and break up with a rod or
wire any lumps which cling to the side of the flask and are not incorporated by the stirrer.
The mixture is finally cooled and the ethereal solution carefully decanted from the solid, which is carefully rinsed twice with
250-cc. portions of dry ether. The united liquids are then distilled from a water bath held at 46–60°, the residue is fractionated with a
column, and the fractions boiling at the following points are collected: up to 110°; at 110–115°; at 115–117°; and at 117–140°. The portion boiling at
115–117° is pure
epichlorohydrin; the lower and higher fractions are systematically redistilled, yielding a further quantity of pure material. The yield is
705–747 g. (
76–81 per cent of the theoretical amount). The residue, varying from 16 to 150 g., consists of nearly pure
glycerol dichlorohydrin, and may be employed in subsequent runs (Note
3).