How Is Aluminium Bromide Hexahydrate Synthesized?

Aluminum bromide hexahydrate (AlBr3.6H2O) can be synthesized by reacting aluminum metal with bromine in the presence of water. The reaction proceeds as follows:

2 Al + 3 Br2 + 12 H2O → 2 AlBr3·6H2O + 6 H2

The reaction is exothermic and requires careful control to avoid overheating or boiling of the reaction mixture. A suitable apparatus for this reaction is a round-bottomed flask fitted with a reflux condenser, dropping funnel, and gas inlet tube.

To carry out the synthesis, aluminum pieces are added to the round-bottomed flask containing water and stirred until dissolved. Bromine is then added dropwise from the dropping funnel while stirring, and the reaction mixture is heated gently to accelerate the reaction. As the reaction proceeds, aluminum bromide hexahydrate will start to form as a white precipitate. The reaction should be stopped once all the bromine has been consumed, which can be detected by the absence of its characteristic reddish-brown color.

After completing the reaction, the mixture is allowed to cool to room temperature, and the solid aluminum bromide hexahydrate is filtered off using a Buchner funnel. The product is washed with cold water to remove any impurities and dried under vacuum to obtain a white crystalline powder.