A
1-l. three-necked flask is fitted with a
sealed mechanical stirrer, a
dropping funnel, and a
dry ice condenser charged with an ice-salt mixture (Note
1).
Three hundred milliliters (240 g., 3.7 moles) of aqueous 70% ethylamine solution (Note
2) is placed in the flask, the stirrer is started, and
200 g. (1.00 mole) of 2,3-dibromopropene (Note
3) is added dropwise over a period of 1 hour. After the addition is complete, the reaction mixture is stirred for 3 hours.
Ether (300 ml.) is added, and the mixture is cooled in an
ice bath.
Sodium hydroxide (100 g.) is added with stirring and cooling. The cold mixture is transferred to a
separatory funnel, and the phases are separated. The organic layer is dried in two stages over
25-g. portions of sodium hydroxide. The organic layer and the small amount of water that separates during the second stage of drying are decanted into a separatory funnel, and the phases are separated. Most of the
ether and unreacted
ethylamine are removed from the organic layer by distillation through a
250-mm. × 13-mm. column packed with glass helices, and the residue is distilled through the same column at reduced pressure under
nitrogen to give
115–128 g. (
70–78%) of
N-(2-bromoallyl)ethylamine; b.p.
53–55° (27 mm.),
79–81° (75 mm.) (Note
4);
n25D 1.4765–1.4770.