Org. Synth. 1957, 37, 32
[Acetic acid, benzoyl-, ethyl ester]
Submitted by J. M. Straley and A. C. Adams1
Checked by Max Tishler and M. A. Kozlowski.
In an open 3-l. three-necked flask, equipped with an efficient mechanical stirrer (Note 1) and two dropping funnels, are placed 500 ml. of water, 250 ml. of technical naphtha boiling at 95–110°, and 195 g. (1.5 moles) of freshly distilled ethyl acetoacetate. The mixture is cooled to 5° with a water-ice bath, and 65 ml. of 33% sodium hydroxide solution (33 g. sodium hydroxide in 100 g. solution) is added. As the temperature is maintained below 10° (Note 2) and the pH near 11 (Note 3), the mixture is stirred vigorously (Note 1), and there are added simultaneously from the two dropping funnels 230 g. (1.62 moles) of benzoyl chloride and 270 ml. of 33% sodium hydroxide solution. This addition should be made during about 2 hours. After addition is complete, the cooling bath is removed, and the mixture is allowed to come to room temperature. In order to ensure complete reaction, the mixture is finally brought to 35° during about 1 hour. The stirrer is then stopped, and the aqueous layer is separated and placed in a 2-l. Erlenmeyer flask (Note 4).
To the mixture is added 80 g. of technical ammonium chloride; then it is stirred slowly overnight. The specific gravity is brought to 1.13 by the addition of about 90 g. of sodium chloride, after which the mixture is transferred to a separatory funnel. About 10 ml. of benzene is used to rinse the flask and is added to the separatory funnel. The aqueous layer is withdrawn (Note 5), and the oil is washed three times with 100-ml. portions of cold water.
An additional 40 ml. of benzene is added (to accomplish drying on distillation), and the product is distilled under reduced pressure, using a short still head with no fractionating column (Note 6). The yield of ethyl benzoylacetate, b.p. 145–150°/12 mm., is 197–203 g. (68–71%) (Note 4).
Good stirring is essential. Slow stirring results in low yields.
Temperatures above 10° did not result in consistently good yields.
Lower pH did not give good yields. The pH was checked by means of filter paper
, which had been dipped in an alcoholic solution of alizarin
and then dried.
layer may be used without further treatment for the next run. Yields of 76%
have been obtained on such a second run without making allowance for recovered ethyl acetoacetate
. Distillation of the naphtha
layer together with the fore-run from the final distillation of ethyl benzoylacetate
yields 11–14 g.
of recovered ethyl acetoacetate
and about 235 ml. of naphtha
As high as 62 g. of benzoic acid
has been recovered by acidification of the aqueous layer.
The chief impurity in the crude ester is a high-boiling material of unknown composition.
The methods of preparation have been listed in two earlier volumes.2,3
The present method, which is an adaptation of a process found in German documents,4
is a shorter, more simple procedure which does not require use of dry solvent or metallic sodium
Chemical Abstracts Nomenclature (Collective Index Number);
ammonium chloride (12125-02-9)
sodium hydroxide (1310-73-2)
sodium chloride (7647-14-5)
Benzoic acid (65-85-0)
benzoyl chloride (98-88-4)
Ethyl acetoacetate (141-97-9)
Acetic acid, benzoyl-, ethyl ester (94-02-0)
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