One kilogram (16.4 moles) of ice-cold ethanolamine (Note
1) is added, through a
dropping funnel, with mechanical stirring, to
7 l. (9.94 kg., 52 moles) of ice-cold hydrobromic acid (sp. gr. 1.42) (Note
2) contained in a
12-l. round-bottomed flask. The flask is attached to an
efficient fractionating column and heated until 1850 cc. of distillate has been collected. The rate of heating is then diminished to a point at which the liquid ceases to distil and merely refluxes. The heating under reflux is continued for one hour. At the end of this time, 700 cc. more is distilled, and the solution is again heated under reflux for one hour. This procedure is followed with 600-, 300-, 250-, 150-, 100-, and 50-cc. portions of distillate. The process may be interrupted at any time. The solution is finally heated under reflux for three hours, and
2.3 l. of crude hydrobromic acid distilled. The total volume of distillate, including that which is collected during refluxing, must not be less than 6270 cc. or more than 6330 cc.
The dark-colored residue is divided into two approximately equal portions, and each is poured, while still hot, into a
4-l. beaker. After the liquid has cooled to about 70°,
1650 cc. of acetone is added to each portion. The mixture is stirred well, so that as much as possible of the dark-colored solid is brought into contact with the
acetone. After standing in the
icebox overnight, the
β-bromoethylamine hydrobromide is collected on a filter, washed with
acetone until colorless (Note
3), and air-dried for about fifteen minutes. The filtrates are combined, concentrated to a volume of 1 l., and cooled. After seeding, a second crop of nearly pure material is obtained. By evaporation to a syrup, cooling, and seeding, a third crop of slightly colored material is obtained. (Note
4). The yield is about
2.8 kg. (
83 per cent of the theoretical amount) (Note
5).