Organic Syntheses, Coll. Vol. 4, p.436 (1963); Vol. 32, p.65 (1952).
In a 1-l. round-bottomed flask
, bearing an efficient reflux condenser (Note 1)
, are placed 286 g. (2 moles) of 2-ethylhexanamide (Note 2)
, 300 ml. of dry benzene (Note 3)
, and 357 g. (218 ml., 3 moles) of thionyl chloride (Note 4)
. The flask is placed in a water bath
, which is heated quickly to 75–80° and maintained at that temperature for 4.5 hours (Note 5)
. The reaction mixture is transferred to a 1.5-l. beaker
and cooled in an ice bath
. A mixture of 100 g. of crushed ice and 100 ml. of water is added to decompose the excess thionyl chloride
. Cold 50% potassium hydroxide
solution is added in small portions, with stirring, until the mixture is alkaline to litmus (Note 6)
. The mixture is transferred to a separatory funnel
, and the layers are separated. The aqueous portion is extracted with 100 ml. of benzene
. The benzene
solutions are combined and washed once with 150 ml. of 1% sodium carbonate
solution and twice with 150-ml. portions of water (Note 7)
. The mixture is distilled from a modified Claisen flask
, the bulk of the solvent being removed at atmospheric pressure. The yield of nitrile is 215–236 g.
); b.p. 118–120°/100 mm. (Note 8)
, (Note 9)
, and (Note 10)
Unless the temperature of the water supplied to the condenser is below 20°, a larger amount of thionyl chloride
may be required. The condenser should be attached to a gas trap
was prepared in 86–88%
yield from technical 2-ethylhexanoic acid (Carbide and Carbon Chemicals Corporation)
by a method similar to that described previously,2
except that the crude amide was filtered directly from the reaction mixture, washed well with water, and dried. The resulting product, which melted at 99–101°
, was used without further purification. If the pure amide is desired, this product may be recrystallized (with 83–90%
recovery) from 50% ethanol
. For 100 g. of amide
, 2 l. of 50% ethanol
is used, and the hot solution is decolorized with charcoal. The product thus obtained is in the form of white needles which melt at 102–103°.
The submitters used Eastman Kodak Company white label grade thionyl chloride
. The checkers purified commercial thionyl chloride (Hooker Electrochemical Company, refined grade)
by the method of Cottle.3
It is advisable to carry out the reaction in a hood
, as hydrogen chloride
and sulfur dioxide
are evolved. The evolution of gases stops just before the end of the specified heating period.
Drying of the solution is unnecessary, since the water present is removed in the next step by azeotropic distillation with benzene
The checkers collected the product at 70.5–72°/10 mm.
also can be prepared by this method in comparable yields, but a longer reaction time (7 hours) is required. The method was found to be unsatisfactory for the preparation of the nitriles of azelaic and phthalic acids from the corresponding diamides.
The submitters prepared palmitonitrile
in more than 90%
yield by heating the amide with a benzene
solution of thionyl chloride
for 6 hours followed directly by distillation. The nitrile so obtained was contaminated with a product having a strong sulfurous odor which could be removed by washing with aqueous mercuric acetate
. By the described procedure, palmitonitrile
free from objectionable odor was prepared in 80%
yield. Troublesome emulsions were formed during the neutralization and washing steps; the addition of a small amount of ethanol
aided in breaking the emulsions.
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