(
A)
Ethoxyacetic Acid.—In a
2-l. round-bottomed flask, provided with a
reflux condenser 70 to 80 cm. long, is placed
1250 cc. of absolute ethyl alcohol (Note
1). Through the condenser tube
69 g. (3 gram atoms) of metallic sodium is added rapidly enough to keep the alcohol refluxing gently. When the
sodium has completely dissolved, a solution of
142 g. (1.5 moles) of chloroacetic acid in
180 cc. of absolute alcohol is added slowly in
20-cc. portions to the sodium ethoxide solution (Note
2). After all the acid has been added, the mixture is heated gently for ten minutes. The excess alcohol is removed as completely as possible by distilling from a
steam bath and finally by passing steam into the residue. The aqueous solution is cooled, and
140 cc. (1.7 moles) of concentrated hydrochloric acid (sp. gr. 1.19) is added. The
sodium chloride is removed by filtration with suction and is washed with two
50-cc. portions of ether. The original filtrate is saturated with dry
sodium sulfate (30–35 g.) and is then extracted with the
ether which was used for washing the precipitate, together with an additional
100 cc. of ether. The
ether is separated from the aqueous layer, and the latter is extracted four times with
100-cc. portions of fresh ether. The
ether is removed by distillation from a steam bath, and the residue is distilled under reduced pressure, using a
500-cc. Claisen flask equipped with a
500-cc. receiver. The acid boils at
109–111°/17–18 mm. and weighs
115–116 g. (
74 per cent of the theoretical amount). By redistilling the low-boiling fraction and collecting the portion boiling at
150–210°, there is obtained an additional
7–10 g. of material which is chiefly
ethoxyacetic acid and may be combined with the main fraction for conversion to the ester.
(
B)
Ethyl Ethoxyacetate.—The
ethoxyacetic acid, which should amount to about 125 g. (1.2 moles), is placed in a
750-cc. Erlenmeyer flask containing
230 cc. (3.9 moles) of absolute ethyl alcohol. The flask is set in a pan filled with cold water (Note
3), and dry
hydrogen chloride is passed into the mixture. After the mixture becomes saturated (Note
4) it is allowed to stand twenty-four hours to ensure the completion of the reaction at room temperature (Note
5). The solution is cooled, and a saturated solution of
sodium carbonate is added cautiously and with stirring to avoid excessive foaming. The addition is continued until the mixture is faintly alkaline to litmus; an excess of
sodium carbonate lowers the yield and should be avoided. The ester is extracted with four
100-cc. portions of ether; the extract is dried with
25 g. of anhydrous potassium carbonate, and the
ether is distilled from a steam bath. The residue is distilled at ordinary pressure. The yield of ester boiling at
153–155° is
110–115 g. (
55–58 per cent of the theoretical amount based on the
chloroacetic acid, or
69–72 per cent based on the
ethoxyacetic acid).