Submitted by R. L. Shriner and H. R. Todd.
Checked by W. H. Carothers and W. L. McEwen.
1. Procedure
In a dry
2-l. three-necked, round-bottomed flask, fitted with a
liquid-sealed stirrer, a
500-cc. dropping funnel, and an
efficient reflux condenser protected at the top with a
calcium chloride tube, is placed
400 cc. of absolute alcohol. Through the condenser tube is added
23 g. (1 gram atom) of clean sodium at such a rate that the solution is kept at the boiling temperature. After the
sodium has dissolved completely,
170 g. (1.06 moles) of ethyl malonate is added, and then
100 g. (1.02 moles) of mesityl oxide (Note
1) is added slowly through the dropping funnel. The solution is refluxed with constant stirring for two hours, after which a solution of
125 g. (2.2 moles) of potassium hydroxide in 575 cc. of water is added and the mixture is stirred and refluxed again on the
water bath for six hours.
The mixture while still hot is made just acid to litmus with dilute
hydrochloric acid (1 volume concentrated acid to 2 volumes water; sp. gr. 1.055); about 550 cc. is required. The flask is fitted with a
condenser set for distillation, and as much alcohol as possible (about 550 cc.) is distilled by heating on a water bath.
The residue in the flask is boiled with about
15 g. of Norite (Note
2), filtered, and the treatment with the decolorizing charcoal repeated. The residue is again neutralized to litmus with dilute
hydrochloric acid (about 150 cc.) and again boiled with charcoal. The hot, neutral or alkaline, yellow filtrate is finally made distinctly acid to
methyl orange with additional dilute
hydrochloric acid (50 to 100 cc.), boiled for a few minutes, and allowed to cool, whereupon the methone crystallizes. The product is filtered by suction from the acid liquid, washed with ice-cold water, and dried in the air. The yield is
96–122 g. (
67–85 per cent of the theoretical amount) (Note
3).
2. Notes
2. Care is necessary when adding the decolorizing charcoal or the hot acid solution may foam vigorously owing to the liberation of
carbon dioxide. A
large container should be used, and the charcoal should be added very slowly.
3. The submitters in carrying out this preparation invariably obtained yields ranging from
120 to 128 g. of a product melting between
145° and 147°. Crystallization from about
1 l. of acetone gave
100 g. (
70 per cent) of pure white material melting at
147°. The checkers (using
mesityl oxide purchased from the Eastman Kodak Co. and freshly distilled) obtained yields ranging from
96 to 112 g., but their product melted at
147–148° and recrystallization failed to raise the melting point. The melting point of methone is given in the literature as
148–150°.
3. Discussion
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