A
1-l. three-necked round-bottomed flask is equipped with a sealed stirrer, a thermometer, a dropping funnel, and an efficient condenser, the upper end of which is protected with a calcium chloride drying tube. In this flask
23 g. (1 g. atom) of lustrous sodium (Note
1) is dissolved in
400 ml. of absolute ethanol (Note
2). The
sodium is cut into about 25 pieces, and the entire amount is added at one time. It may be necessary to cool the flask in a cold-water bath if the reaction becomes violent. When all the
sodium has dissolved, the solution is cooled to 50° and
130 g. (127 ml., 1 mole) of ethyl acetoacetate (Note
3) is added dropwise while the temperature is maintained between 45° and 50°. The resulting solution is cooled to about 35°, and
92.5 g. (78.4 ml., 1 mole) of epichlorohydrin (Note
4) is added dropwise with stirring over a period of 20 minutes. The temperature is then raised to 45° and is kept at 45–50° for 18 hours. The clear red-orange solution is cooled to 15°, and chilled
glacial acetic acid (60–65 ml.) is added with stirring until the solution is just acid to litmus; a mush of
sodium acetate crystals precipitates. The dropping funnel is replaced by a
capillary tube, and the condenser is set for distillation. About three-fourths of the
ethanol is removed under reduced pressure while air is bubbled into the mixture through the capillary tube (Note
5). Care is taken that the internal temperature does not exceed 100°.
The mushy residue is shaken with 250–300 ml. of water until the
sodium acetate dissolves. The oily layer of lactone is separated, and the aqueous phase is extracted with two
100-ml. portions of ether. The combined oil and
ether extracts are washed with 150 ml. of water and dried overnight over
anhydrous sodium sulfate. The
ether is removed under reduced pressure, and the product is distilled from a
modified Claisen flask. The fraction boiling at
160–170°/11 mm. is collected; refractionation yields
107–114 g. (
61–64%) of product boiling at
164–168°/11 mm. or
151–156°/8 mm.;
n25D 1.4815–1.4830 (Note
6) and (Note
7).