Purpose and Introduction
The halogenation of of trans-cinnamic acid using pyridinium tribromide was connected in the organic solvent glacial acetic acid in order to verify and test which addition mechanism the reaction would follow. In the anti-addition mechanism, bromines attach themselves on opposite sides of the alkene functional group in a compound. In a syn-addition, the attach to the same side of the alkene.
The reaction synthesis was completed by using a reflux system to produce to crude product, and a vacuum filter to yield a solid, crude product. Recrystallization of the solid product was performed, allowing the impurities of the solid to be removed while slowly crystallizing and the product. The melting point of the final recrystallized product was taken to compare and …show more content…
The yield of the recrystallized product obtained was 0.246 g. The percent yield obtained was: percent yield =actual yieldtheoretical yield x 100%=0.246 g0.250 g x …show more content…
The key piece of data was the comparison between the melting point ranges of the unknown enantiomer and the known product of (2S, 3R)-2,3,-dibromo-3-phenylpropanoic acid. The mechanism which produced this product was the anti addition mechanism for the bromination of trans-cinnamic acid because the other mechanism would have produced a product with a significantly lower melting point. In order to determine the percent recovery, a mass of the completely dried crude product should have been taken. Differentiating between the (2R, 3S and 2S, 3R) enantiomer to determine the exact product could have been performed to observe the optical rotation using a