Org. Synth. 1930, 10, 80
Submitted by C. F. H. Allen and R. K. Kimball.
Checked by J. B. Conant and Helen O'Brien.
The following preparation, through the filtration of the crude solid and washing with water, should be carried out in a hood with a good draft.
Into a 5-l. flask or bottle, set in a water bath and fitted with a stirrer, thermometer, and separatory funnel, are placed 208 g. (1 mole) of benzalacetophenone (Note 1), 3.5 l. of 95 per cent ethyl alcohol (Note 2), and 60 g. (1 mole) of glacial acetic acid (Note 3). The mixture is warmed with stirring to 35°, and a solution of 130 g. (2 moles) of potassium cyanide in 375 cc. of water is added from the separatory funnel over a period of about fifteen minutes. The initial greenish color changes to yellow after all the acetic acid has reacted and the solution has become alkaline (Note 3). Stirring is continued for three hours, the temperature being maintained at 35°. During this time about half of the nitrile crystallizes. The flask is then loosely stoppered and left in a cool place for about fifty hours (conveniently out-of-doors in cold weather, but out of direct sunlight), after which the solid is filtered and washed, first with 500 cc. of cold 50 per cent alcohol, and then with water until free from potassium cyanide (silver nitrate test). The yield of air-dried material melting at 125° is 220–227 g. (93–96 per cent of the theoretical amount). This product is sufficiently pure for most purposes, although it contains traces of a high-melting substance. If a product of higher melting point is desired, it may be recrystallized from 1 l. of 95 per cent alcohol or 375 cc. of acetone. Pure phenylbenzoylpropionitrile melts at 127°.
The preparation may be carried out in a more concentrated solution (1 l. of alcohol
) with the same yield, but an inferior product is obtained. If this is done, it is best to stir for fifteen minutes at 50° after all the cyanide has been added and then cool in tap water. Since the product separates as an oil from a solution of this concentration, it is best to inoculate with a crystal of the nitrile.
If the solution becomes too alkaline, the nitrile formed will add to a second molecule of unsaturated ketone so readily that the product will consist almost entirely of a high-melting (284–286°) substance. For this reason it is essential to measure the acetic acid
accurately; if too much is used, addition of hydrocyanic acid
will not take place.
has been prepared by the action of sodium or potassium cyanide
or benzalacetophenone dibromide
and by the addition of hydrocyanic acid
in the presence of sodium or potassium cyanide
This preparation is referenced from:
Chemical Abstracts Nomenclature (Collective Index Number);
acetic acid (64-19-7)
hydrocyanic acid (74-90-8)
silver nitrate (7761-88-8)
potassium cyanide (151-50-8)
Benzalacetophenone dibromide (611-91-6)
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