Alkyl Halide: A Nucleophilic Substitution Reaction

Synthesis of an Alkyl Halide: A Nucleophilic Substitution Reaction
Unknown Letter: B
23 April 2013

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Purpose:
The purpose of the experiment was to perform a synthesis of an alkyl halide by a nucleophilic substitution reaction. The alkyl halide, along with the starting
Through the top of the condenser, 14 mL of concentrated sulfuric acid was added drop wise over a period of ten minutes. The addition of the acid created a change in color of the solution to a rustic orange color. The mixture was refluxed for 30 minutes and the solution changed to a faded yellow-orange color. Once reflux was complete, a simple distillation was set up, with the 25 mL collection graduated cylinder placed in an ice bath. The mixture was distilled and combined with the hood partners’ distilled mixture. The distillate was placed in a separatory funnel with 10 mL of distilled water. Once separated, the distillate was added to the funnel again with 9 M sulfuric acid. The organic layer was still in the funnel after separation, as distilled water was added to the solution and then 10 mL of a saturated solution of sodium bicarbonate. The organic solution was dried with anhydrous sodium sulfate for a week. The liquid product was transferred to a 25 mL round bottom flask equipped with a stir bar and a simple distillation was set up. The solution was distilled and the density of the bromide was calculated at 1.222 grams/mL with a boiling range of 87-92◦C. The theoretical yield was calculated at 12.847 grams and the percent yield was 72.3 percent. Next was the characterization and assessment of the purity of the
Since the closeness of two, the sample could be considered fairly pure. The area percentage of 1.636 retention time was listed as 95 percent, with only a little less than 5 percent of the area being impure.
Physical Properties- the physical properties were not the main source for determining the identity of the alkyl halide and starting alcohol because of the usual inaccuracy, however the results for boiling point and density proved close to 2-bromobutane and 2-Butanol. The boiling range from the week one experiment was 76-118 ◦C, which was too large of a range and the alkyl halide had not been completely purified. However, the boiling point for 2-butanol alcohol was about 83 ◦C, which lies within the range of the starting boiling range.
The boiling range for the product was 87-92 ◦C which closely related to boiling point of 2-bromobutane at 91 ◦C. The density was calculated to 1.222 g/mL with 2-bromobutane being 1.255 g/mL. The density of the product was not significant in identifying the halide because it was too closely related with 1-bromopentane as well. Physical properties are helpful in determining the identity of products but are never significant enough to confirm the identity of the