Preparation of isoamyl bromide
Alternative Names: 1-bromo-3-methylbutane; isopentyl bromide; 3-methylbutyl bromide; butane, 1-bromo-3-methyl-;
Preparation of isoamyl bromide from isoamyl alcohol and hydrobromic acid
A 1-liter two-necked round-bottomed flask is fitted with a dropping funnel and a wide bent tube connected to a long efficient condenser set for downward distillation and a receiver. 142 ml (or 210 grams) of 48% hydrobromic acid are placed in the flask and 33 ml (or 60 grams) of concentrated sulfuric acid are added in portions, with shaking. When cold, 109 ml (or 88 grams) of isoamyl alcohol (isopentyl alcohol; 3-methyl-1-butanol ) are slowly added in small portion to the mixture of sulfuric and hydrobromic acids. 5.5 ml (or 10 g) of concentrated sulfuric acid are slowly added from the dropping funnel and the obtained isoamyl bromide is slowly distilled and collected in an ice cooled receiving flask. The crude isoamyl bromide is washed with an equal volume of concentrated hydrochloric acid, then with water, a little 5% sodium bicarbonate solution, and finally with water. The isoamyl bromide is dried with anhydrous calcium chloride. The isoamyl bromide is purified by distillation. The fraction passing over 117-120° C is collected in a receiver cooled in ice, yielding 125 grams of pure isoamyl bromide.
A text book of practical organic chemistry, by A. I. Vogel, 279, 1974