A solution of
123 g. (67 cc., 1.2 moles) of sulfuric acid (sp. gr. 1.84) in 370 cc. of water is placed in a
2-l. round-bottomed flask equipped with a
reflux condenser. To this is added
98.5 g. (0.81 mole) of diallylcyanamide (p. 203) and a few pieces of
clay plate to prevent bumping. The mixture is refluxed gently for six hours. During the first fifteen minutes of heating, some bumping occurs. However, the mixture gradually becomes homogeneous and the boiling then proceeds smoothly (Note
1).
After six hours, the solution is cooled to room temperature and a cold solution of
192 g. (4.8 moles) of sodium hydroxide in 350 cc. of water is poured down the side of the flask so that most of it settles to the bottom without mixing with the solution in the flask. The flask is then connected to a condenser for downward distillation and is shaken to mix the two layers. The resulting free amine separates. The flask is heated and the amine, together with some water, distils. The distillation is continued until no amine separates from a test portion of the distillate. There is a small quantity of an oily liquid left floating in the flask. This is probably an impurity from the
diallylcyanamide.
The weight of water in the distillate is estimated, and about one-half of this amount of
potassium hydroxide is added in the form of sticks, so that it will dissolve slowly. The mixture should be kept cool while the
potassium hydroxide is dissolving. Bubbles of
ammonia gas will be evolved. When solution of the
potassium hydroxide is complete, the amine is separated and dried for several hours over solid
sodium hydroxide which has been freshly broken up into small lumps. It is then filtered into a
distilling flask and distilled at atmospheric pressure. If the product has been thoroughly dried, there should be no low-boiling material. All the
diallylamine should come over at
108–111° and only a very small amount of higher-boiling material should remain. The yield is
62–68 g. (
80–88 per cent of the theoretical amount) (Note
2).