Wittg Synthesis Of 1,4-Diphenyl-1,3-Butadiene

Purpose of Experiment
The purpose of this experiment was synthesize 1,4-Diphenyl-1,3-butadiene from benzyl triphenylphosphonium chloride and pure trans-cinnamaldehyde using Wittig reaction process to convert the carbonyl group in trans-cinnamaldehyde into a carbon carbon double bond.


Results
The weight of the product from the experiment was 0.156g, and the melting point obtained was 145°C. Therefore, the product was 1,4-Diphenyl-1,3-butadiene, which has a melting point in the range of 151-153°C, because it has a melting point which is closer to that of the unknown.
Below is the percent yield of the product obtained :
Mole of product is 1mmol because of 1:1 mole ratio of 1,4-Diphenyl-1,3-butadiene with trans-cinnamaldehyde
(1mmol )/(206.29g/mol) = 0.206grams of 1,4-Diphenyl-1,3-butadiene
Percentage yield = (0.156g )/0.206g x 100%=75.6%

Discussion
The yield obtained from the experiment was 75.6% of the actual yield. The discrepancy might have been from the design of the experiment. Before and after the aqueous sodium hydroxide was added to the reaction, the reaction was supposed to be mixed thoroughly in order to facilitate the reaction between the compounds added.The discrepancy might have resulted from incomplete reaction between the reaction constituents.
The lower yield of product might have been from the separation of the aqueous and the organic layer after washing the crude product. Pipetting away the product along with the aqueous layer might have resulted from a reduced product of 1,4-Diphenyl-1,3-butadiene.
The melting point obtained from the solution was 145°C , and differed from the actual melting point by 6-8°C. The discrepancy in the result might have been from the equipment used. The solution was inserted into the machine while it was warm (about 60°C). This might have led to the lower boiling point.
The obtained product was 1,4-Diphenyl-1,3-butadiene because the melting point was very similiar to that of the predicted product. The physical features such as color, which was white, melting point, melting point, texture and so on was also similar to that of the predicted product.

Conclusion
The method of characterization used in this experiment supports purity of the product obtained. The product was much like the hypothesized.
The purpose of the experiment was to synthesize 1,4-Diphenyl-1,3-butadiene using the Wittig reaction. The objective and purpose of the experiment was obatined with the method that was implemented to synthesize and purify the product. One way this experiment could be improved is the strictly follow the procedures, and avoid taking the melting point with a system that is not at room temperature.