1. Preparation of ethyl bromide from ethyl alcohol and hydrobromic acid
Start with a 1-liter double neck round bottom flask with a drop funnel and wide bend. The bend is connected to a long and efficient condenser assembly and receiver for downward distillation. First, place 281ml (or 415 g) 48% hydrobromic acid in a flask, then add 65ml (or 120 g) of concentrated sulfuric acid in batches, while shaking. As it cools, a small quantity of 145ml (or 100 g) 95% ethanol is slowly added to the mixture of sulfuric acid and hydrobromic acid. Then 109ml (or 200g) of concentrated sulfuric acid is slowly added to the drop funnel, and the ethyl bromine
obtained by slow distillation is collected in the cold receiver flask. The crude ethyl bromine was washed with equal volume of concentrated hydrochloric acid, then washed with water and a small amount of 5% sodium bicarbonate solution, then washed with water, and finally dried the ethyl bromine with anhydrous calcium chloride. The crude ethyl bromide is purified by distillation and 205 grams of pure ethyl bromine is obtained.
2. Preparation of ethyl bromide from ethyl alcohol and potassium bromide
Add 50g of concentrated sulfuric acid to 25g of ethanol and let it cool under continuous stirring. Pour in 60g of powdered potassium bromide and let the mixture rest overnight. The next day, the ethyl bromine is distilled and washed, washed with dilute sodium carbonate solution and water. Finally, the obtained bromoethane was dried and re-steamed with calcium chloride.
3. Preparation of ethyl bromide from ethyl alcohol and bromine
Place 60g of ethanol and 10g of red phosphorus in a round bottom flask cooled with cold water. Then 60g of bromine was slowly added to the droplet funnel while the mixture was stirred and cooled. When all the bromine is added, stir the mixture for another hour. The ethyl bromide is then distilled and washed with dilute sodium carbonate solution and distilled water. Finally, using calcium chloride ethyl bromide and distillation, got in 38 ℃ boiling colorless heavy liquid.