In a
2-l. three-necked flask equipped with a mechanical stirrer, a thermometer, and a dropping funnel is placed
185 g. (0.55 mole) of technical barium hydroxide octahydrate. The flask is heated on a
steam bath in a
hood. When the
barium hydroxide has dissolved in its water of crystallization, the stirrer is started and
70.1 g. (1.00 mole) of β-aminopropionitrile (p. 93) is added dropwise over a period of 40 minutes. The temperature is maintained at 90–95° during the addition and for 40 minutes thereafter. Forty grams of asbestos filter aid (Note
1) and 1 l. of hot water are added, and the mixture is saturated with
carbon dioxide (Note
2) while the temperature is held at 85–90°. The mixture is filtered with suction, the precipitate is returned to the flask with 500 ml. of hot water, and the mixture is heated and stirred for 20 minutes. After the
barium carbonate has been filtered the washing procedure is again repeated with a second 500 ml. of hot water. The combined filtrates and washings are concentrated under reduced pressure on the steam bath (Note
3) until solid material separates. To the residue are added 200 ml. of hot water and
0.5 g. of decolorizing carbon (Note
4). The resulting solution is warmed on the steam bath for a few minutes and then filtered into a weighed
500-ml. Erlenmeyer flask. The flask is heated on a steam bath, and a jet of clean compressed air is directed at the surface of the solution. When the total weight of the solution is 130 g., it is cooled to 15–20° and diluted slowly with
400 ml. of methanol. After the solution has stood for several hours in the refrigerator, the product is filtered with suction and washed with two
100-ml. portions of methanol. The yield of
β-alanine melting at
197–198° (dec.) is
75–80 g. (
85–90%).