To Prepare N-Butyl Bromide Or N-Bromobutane
The objective of this lab was to prepare n-butyl bromide or n-bromobutane, which is derived from an alcohol and an acid. In this case, n-butyl alcohol and sulfuric acid were the reagents. There were two methods of distillation that was involved in this experiment. The first was by reflux distillation, which is used to speed up a chemical reaction without having the reactants/ products evaporate or explode. Data Table 1 indicates the amount of each reagents that was prepared for the reflux apparatus. However, the reagents, sodium bromide, water, and butanol, were combined and cooled in an ice bath previously before transferred to the apparatus. Sulfuric acid was then slowly added to the cooled mixture, causing the solution to turn a dark yellow.
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During the reflux period, there have not been any signs of errors; the reflux distillation process occurred smoothly. Once reflux distillation was completed, the mixture was cooled to room temperature, then extracted thrice by a separatory funnel. Before any extractions proceeded though, the mixture already had two distinct layers – a top dark brown layer, and a bottom light yellow layer. This mixture was extracted with 9M sulfuric acid, and the aqueous layer, containing butanol, sulfuric acid, and water, was removed and discarded. The organic layer, consisting of the n-butyl bromide, went through a second extraction with water. This resulted in an organic layer of n-butyl bromide and water and an aqueous layer of water and a little amount of alcohol, which was discarded. The organic layer was then dried by extracting it with sodium bicarbonate; this is an extra step for drying the alkyl halide. The resulting organic layer contained the crude n-butyl bromide, and the drying procedure was completed by adding anhydrous calcium chloride until the solution turned clear. The drying agent was used to absorb any excess water and thus, resulted in a clear solution of n-butyl
During the reflux period, there have not been any signs of errors; the reflux distillation process occurred smoothly. Once reflux distillation was completed, the mixture was cooled to room temperature, then extracted thrice by a separatory funnel. Before any extractions proceeded though, the mixture already had two distinct layers – a top dark brown layer, and a bottom light yellow layer. This mixture was extracted with 9M sulfuric acid, and the aqueous layer, containing butanol, sulfuric acid, and water, was removed and discarded. The organic layer, consisting of the n-butyl bromide, went through a second extraction with water. This resulted in an organic layer of n-butyl bromide and water and an aqueous layer of water and a little amount of alcohol, which was discarded. The organic layer was then dried by extracting it with sodium bicarbonate; this is an extra step for drying the alkyl halide. The resulting organic layer contained the crude n-butyl bromide, and the drying procedure was completed by adding anhydrous calcium chloride until the solution turned clear. The drying agent was used to absorb any excess water and thus, resulted in a clear solution of n-butyl