Hydrocinnamic Acid And N-Bromination Synthesis

Hydrocinnamic acid underwent bromination using N-bromosuccinimide and AIBN. As one lab partner set up the reflux apparatus, the other measured the chemicals used in the lab experiment. 2.10 g of hydrocinnamic acid was used. It was observed as white and had a slight cinnamon smell. The amount of NBS was 2.49g and was measured in the fume hood. AIBN was measured at .030 g. 10 mL of acetic acid was also obtained. The reflux apparatus consisted of a 25 mL flask with a stir bar in a water bath. The chemicals were added in the following order: hydrocinnamic acid, NBS, AIBN, and acetic acid. After they were added, the temperature was turned up to come to a constant temperature around 80 C. A condenser was placed on top of the flask so if any evaporated
The final temperature was 76. The time duration for the bromination was 3:30 pm to 4:28 pm, which was 58 minutes. The flask was set out to cool. No changes occurred while it cooled. The next task was to precipitate the brominated hydrocinnamic acid from the solution. Even though BHCA has a polar carboxyl group, it has only a slight polarity due to its 9 carbon atoms. To precipitate it out, the solution was mixed added to 100 mL of ice water in a 250 mL flask. This flask was in an ice bath because low temperatures reduce solubility. The solution was added to a flask with a plastic pipette. The mixture was stirred at high speed. The mixture turned cloudy and white. The temperature was 3. The mixture was then poured through a Buchner funnel using vacuum filtration. The water and succinimide (the other product formed) collected in the flask below the funnel. This was the filtrate. BCHA stayed on top of the filter paper in the funnel. This was the precipitate. It was observed as a white powder. A beaker was pre-weighed at 14.40 g. The beaker was labeled and then the precipitate was added. The beaker was stored with no lid so the water will evaporate for the next lab